Advances in Legumes for Sustainable Intensification

By Sandeep Kumar

Advances in Legume-based Agroecoystem for Sustainable Intensification explores current research and future strategies for ensuring capacity growth and socioeconomic improvement through the utilization of legume crop cultivation and production in the achievement of sustainability development goals (SDGs). Sections cover the role of legumes in addressing issues of food security, improving nitrogen in the environment, environmental sustainability, economic-environmentally optimized systems, the importance and impact of nitrogen, organic production, and biomass potential, legume production, biology, breeding improvement, cropping systems, and the use of legumes for eco-friendly weed management.

This book is an important resource for scientists, researchers and advanced students interested in championing the effective utilization of legumes for agronomic and ecological benefit.

• Focuses on opportunities for agricultural impact and sustainability
• Presents insights into both agricultural sustainability and eco-intensification
• Includes the impact of legume production on societal impacts such as health and wealth management

• Language: English
• Publisher: Academic Press
• Release date: Jun 29, 2022
• ISBN: 9780323886000

Book preview

Section I

Legumes for sustainable crop intensification

1. Legume-Based Agroecosystem for Sustainable Intensification: An overview 3

2. Scope for production of pulses in rice fallow lands in South Asia 9

3. Sustainable intensification in cropping systems through inclusion of legumes 27

4. Legumes for efficient utilization of summer fallow 51

5. Efficient utilization of rice fallow through pulse cultivation 71

6. Legumes for nutrient management in the cropping system 93

7. Residual nitrogen for succeeding crops in legume-based cropping system 113

8. Legumes for eco-friendly weed management in agroecosystem 133

Chapter 1

Legume-based agroecosystem for sustainable intensification: An overview

Ram Swaroop Meenaa, Sandeep Kumarb

aDepartment of Agronomy, Institute of Agricultural Sciences, BHU, Varanasi, Uttar Pradesh, India

bICAR-Indian Agricultural Research Institute, Regional Station, Karnal, India

1.1 Introduction

Climate change, as well as the biotic and abiotic stresses to which crop systems will be increasingly exposed, will have major consequences for world food production (Yadav et al., 2015). By 2050, the world’s population will have grown to 9.6 billion people (United Nations, 2013), posing a number of global concerns, the most pressing of which are ensuring food security, mitigating the risk of climate change by reducing net greenhouse gas emissions, and meeting the growing need for energy. To address these issues, a policy framework must be designed in which the long-term sustainability of production system is emphasized. Grain legumes and legume-inclusive agricultural systems can play an essential role in this setting by providing numerous functions while adhering to sustainability standards.

Grain legumes are worldwide fundamental source of high-quality food and feed for diverse and healthy diets that may largely reduce diet-related health issues. As a result, in agricultural and food systems, producing sustainably is becoming increasingly important. In this situation, legumes could play a crucial role by providing diverse ecosystem services while adhering to sustainability principles (Vanlauwe et al., 2015). Legume crops fix free atmospheric nitrogen (N), deliver high-quality organic matter into the soil, and promote efficient soil nutrients cycling and water retention. In addition to their several advantages, legumes help to cut greenhouse gases (GHGs) emissions by producing 5–7 times less GHGs per unit area than that of other crops, and they save fossil fuel energy in the system owing to their lesser requirement for N fertilizer, water, labor, and other inputs. Due to the environmental and socioeconomic benefits of grain legumes, they could be introduced in nonlegume-based cropping systems to increase crop diversity and sustainability of agroecosystem. The production gap for grain legumes can be filled by intensifying cropping system by bringing more areas under legumes and/or by improving their productivity through agronomic and breeding interventions. They can be well introduced in rice fallow, summer fallow, intercropping systems, and agroforestry system that are very important for their horizontal intensification. As legume itself work as an efficient nutrient and weed manager that helps to increase system yield as a whole. The yield potential of grain legumes could also be improved greatly through advancing agronomic and breeding approaches including participatory plant breeding, genomics, molecular breeding, etc. Hence, investments to advance legume breeding will be essential to design diverse cropping systems that strike a balance between productivity, sustainability, and nutritional quality.

Undoubtedly, legume crops play a crucial part (Voisin et al., 2014): (1) at the food-system level, as a source of plant proteins for human and animal consumption, (2) at the production-system level, due to their ability of biological nitrogen fixation and greenhouse gases (GHGs) emission reduction potential, making them potentially highly suitable for inclusion in low-input cropping systems (Lemke et al., 2007), and (3) at the cropping-system level, as a means of diversifying agroecosystem. In this line, we call for better cooperation among policymakers, legume breeders and farmers to develop a versatile and nutritive legume cultivar that lowers soil degradation and reliance on external inputs, improves climate change adaptability, resistance to emerging biotic and abiotic stresses, and their contributions to farming system productivity for sustainable intensification of the agroecosystem. Grain legumes are important to agroecosystem sustainability, especially where resource scarcity is the main production restriction Due to their ability to fix atmospheric nitrogen (N), legumes play a vital role in sustainability of the cropping system; they provide nutrient-rich organic matter into the soil and can mitigate other constraints by improving fertilizer uptake, reducing soil erosion and degradation, suppressing weeds, mitigating climatic stress, and other benefits (Sanginga et al., 2003). Because legumes fix nitrogen with a smaller greenhouse gas footprint than fertilizer N, the relationship between legumes, sustainable intensification, and enhanced farmer livelihoods is easy to make. Furthermore, legumes provide organic inputs that improve crop yields by enhancing soil’s physical, chemical, and biological attributes, and their associated biochemical processes. Thus, sustainable soil management is important to provide food and nutritional security for present and future generations. The 68th United Nations (UN) general assembly declared 2016 the International Year of Pulses to raise awareness and to celebrate the role of pulses in human nutrition and welfare. Likewise, the assembly already declared the International Year of Soils 2015 to create awareness about the role of healthy soils for a healthy life, and the International Union of Soil Science (IUSS) has declared 2015–2024 as the International Decade of Soils (IUSS, 2015).

This book provides an overview of the sustainable intensification of legume-based cropping systems and their role in ensuring the long-term sustainability of agroecosystems, as well as the larger issues of food security and nutrient-rich healthy grain-legume-based diets, ecosystem services, utilization of fallow period, and other social, economic, environmental, and soil-related challenges.

1.2 Vertical intensification of legumes

Besides, increasing areas under grain legumes, the production of grain legumes can be ensured by improvement in grain yield through enhancement in genetic potential through breeding approaches as well as agronomic improvements (Fig. 1.1). Legume itself is an efficient N manager in cropping systems owing to their inherent potential of biological N fixation. Naturally, they fix a considerable amount of atmospheric N and deposit that fixed N into the soil that is available to the succeeding nonleguminous crops. Also, at the initial stages of crop growth, legume crops grow fast and cover soil surface quickly, hence have to smother effect on weed growth. So, upon inclusion of these crops in the system considerably improve the system yield as a whole. Besides, breeding of grain legumes for enhancing their genetic gain is also a prominent way for production improvement of these crops. These approaches mostly include participatory breeding, molecular breeding, genomics, and postgenomics tools.

Fig. 1.1 Sustainable intensification of agroecosystem through inclusion of legumes.

1.3 Horizontal intensification of legumes

The uncertainty of the favourable climate for continuous farming in many regions of the world limits the production of grain legumes for catering to the needs of the increasing population and changing food consumption patterns. Fallow cropping is a primary one and has been employed successfully to alleviate the challenges caused by unfavourable climate for farming (Fig. 1.1). The traditional fallow system (weed fallow or bare fallow) is the oldest technique wherein the land is left uncultivated for a certain period to restore the soil nutrient status and soil moisture. Cultivation of short duration legumes during a fallow period not only provides additional income but also restores the land faster than during the fallow period. These species are well suited for a fallow system due to biological nitrogen fixation, moderate drought tolerance, less water demanding, a wider range of annual and perennial crops, requiring less maintenance, suppressing weed control, improving the soil properties, and controlling soil erosion. Legumes in the fallow areas improve the N and soil organic matter more sustainably. The legume-based fallow system is ideal in rice (Oryza sativa L.) fallow as well as during summer fallow for smallholder farming and nutrient-depleted soils due to continuous cultivation. For instance, in South-Asia only, about 22.3 M ha areas are under rice fallow of which 88.3% falls only in India. This region is under immense pressure to intensify and diversify the cropping system to meet the food and nutritional demand of the growing population.

Therefore, targeting rice fallow for legume cultivation offers a win–win scenario for increasing and diversifying the food production system to meet the increasing food and nutritional demands. Likewise, in the summer season after harvesting of winter season crops and before sowing of monsoon/rainy season crops remains fallow that is called summer fallow. The efficient utilization of these fallows through grain legumes will ensure soil moisture conservation, considerable N addition and cycling in soil, additional crop yield, improvement in soil properties, soil erosion control, employment generation, and extra gain in income. Besides, the areas under grain legume can also be expended by their cultivation in areas already occupied by some type of crops, for example, intercropping with wide-spaced crops and agroforestry system (Fig. 1.1).

1.4 Improved human nutrition, health, and livelihood

Legumes have been consumed by humans for thousands of years in a variety of ways, including feed, fodder, fuel, and litter. Legumes are nutrient-dense foods with a low energy density and a high nutritional profile. Legumes are a cost-effective and rich source of plant-based protein (20–25%), almost double of cereals. They are also a good source of lysine, an important amino acid, unlike cereals. In addition to protein, legumes include a variety of phytochemicals that are important for human health. Low glycemic index carbohydrates, minerals, vitamins, resistant starch, dietary fiber, oligosaccharides (mainly raffinose), essential fatty acids, carotenoids, and polyphenols are abundant in them (Bazzano et al., 2001). They are a good source of vitamins B, iron, zinc, calcium, magnesium, selenium, phosphorus, copper, and potassium. The oil-rich grain legumes (soybeans and groundnut) are high in linoleic acid (21–53%), as well as alpha-linolenic acid (4–22%) (Kouris-Blazos and Belski, 2016). As a result, supplementing cereal foods with nutrient-dense grain legumes may be the most effective recommendation to combat malnutrition. They outperform other dietary supplements due to their lower fat content when compared to the majority of cereals (Rani et al., 2019).

1.5 Improved animal health

Grain legumes are substantially used as animal feed and substrate in the biofuel industry in developing countries (Voisin et al., 2013). In the biofuel business in developing nations, grain legumes are widely used as animal feed and substrate. They are an important source of protein in animal feed, primarily for balancing amino acids in the ruminant and nonruminant production systems. Common grain legumes have a crude protein concentration of 20–30% and are low in carbohydrates, antinutritive compounds, and sulfur-containing amino acids. Quality green fodder, as well as concentrates and dry mass-produced from small-seeded leguminous plants, can be utilized as a feed additive for nonruminants (Kwiatkowska et al., 2017). Groundnut cake, which is generated after the oil extraction from the kernel, contains about 42% crude protein with a high biological value, is frequently used as livestock feed in the Indian subcontinent. Similarly, soybean meal, which is derived from soybean seeds after oil extraction, contains about 47–49% protein and has the best amino acid profile for chicken growth. Cowpea is a grain legume with a high protein content of 24% that is occasionally used as a protein supplement in animal feed during the milking stage. Dual-purpose cowpeas can be used for both human and livestock feed that helps to meet the needs of smallholder farmers.

1.6 Improved human and animal’s dietary energy

Carbohydrates and fats are the major sources of energy to meet grazing livestock (ruminants) requirements for maintenance, growth, production, and work. In the case of carbohydrates, the bulk of the energy comes from the structural polysaccharide. The feed energy requirements of livestock are a major cost in animal production agriculture even for ruminant livestock that can obtain most of their energy needs from relatively cheap fibrous feed materials such as forages. For ruminants, forage nonstructural carbohydrates (e.g., starch and fructosans) and structural polysaccharides (cellulose and hemicellulose) of the plant cell fraction are the primary sources of energy for ruminants (Johansen et al., 2018). The net energy derived from forage feed is closely linked to the digestibility of the structural carbohydrate fraction and the recalcitrant lignocellulose matrix of the biomass material which is an indication of the overall quality of the forage (Adesogan et al., 2019). Even though grasses have greater fiber concentration (a significant component of carbohydrates) than legumes, the higher degradability of forage legumes (e.g., 76–79% for white clover) relative to grasses (e.g., 63% for perennial ryegrass), and the overall greater DMI makes legumes a significant contributor to the energy needs of grazing livestock (Johansen et al., 2018). While not all nutritional attributes of temperate legumes can be given to tropical legumes, the literature solidifies legumes’ inclusion in forage livestock production systems as an important contributor to the net energy requirements of ruminant livestock.

1.7 Legumes for nitrogen and weed manager in cropping system

Legume-based cropping system intercropped with nonlegumes (i.e., cereals) not only favor succeeding crop yield but also favours the whole agroecosystem by reduction of weeds, pest and disease infestation and increasing the soil water availability and OM, improving soil structure and enhancing soil health by stimulating microbial activity and biomass (Raseduzzaman and Jensen, 2017). There are several studies to claim that legume has a very crucial role in maintaining soil fertility by reducing the inorganic N requirement, P solubilization by secreting several organic acids and chelating agents, increasing microbial population and their enzymatic activity. The key part of the residual N is obtained from rhizodeposition and recoverable debris which become part of the active soil organic matter (SOM) pool that derives the N pool in soil for the long term. This also showed that labile pool was utilized by microbes forming microbial biomass releasing N gradually in the following seasons (Wang et al., 2020).

The inclusion of legumes in the cropping systems has seen better weed control along with maintenance of sustainability of production system (Stanari et al., 2017). These fast-growing works well as a rotation crop, inter-crops, cover crop, green and brown manure as well as their residue incorporation and retention on soil surface. Also, intercropping of wheat and chickpea significantly decreased the weed dry weight and number over the sole crop wheat (Banik et al., 2006).

1.8 Breeding for enhancing yield potential of grain legumes

There are a number of abiotic, biotic, and edaphic factors by which legume production is challenged, globally. In addition, legumes have narrow genetic base hence, not gained full potential of production. Although classical breeding approaches have been deployed extensively for legume improvement, but the favorable genetic gain was attained at very slower rate. However, in last few decades, the development of legume genomic resources and their application in breeding programs have made a revolutionary achievement in legume production. The advancements in generation of legume genetic maps, next-generation sequencing tools, gene assembly and annotation, trait mapping, synteny and structural variant analyses, and omics, etc. have secured sustainable food production against climate change, in addition facilitating nutritional scarcity. Therefore, novel genomics and postgenomics tools have been widely utilized by the plant breeders in amalgamation with the new breeding strategies like marker-assisted selection (MAS), marker-assisted recurrent selection (MARS), and high-throughput phenotyping around the world. In developing countries, the level of adoption of improved varieties and availability of quality seeds are still limited hence, participatory plant breeding has provided hundreds of adapted varieties of minor legumes in such countries lacking robust seed systems. In climate-changing scenario, participatory plant breeding and plant varietal selection has shown better impact on legumes productivity via connecting them to an efficient seed supply system at the local level.

With the progression in novel sequencing technologies, the employment of genomic-assisted breeding tools to develop climate-resilient and biofortified legumes have increased significant genetic gain. The implementation of rapid generation advancement through speed breeding and extended application to create the novel variants for multiple genes in one generation will open new avenues to develop climate-resilient grain legumes ensuring their sustainable production. To fulfil grain legumes demand, it is vital to emphasize on the adoption of these novel advanced breeding and agronomic technological interventions for their genetic improvement and production. In addition, it is also crucial to endorse their cultivation through appropriate policies and action plans.

1.9 Protection of soil from erosion and degradation

Human activities have a negative impact on the physical, biological, and chemical attributes of soil, affecting its ability to fulfil ecosystem services and deliver social benefits. Human-caused soil degradation has emerged as one of the most serious ecological and socioeconomic challenges, with the potential to affect food security, production, livelihood, and the availability of other ecosystem services and products of billions of peoples. Around 40% of cultivated areas worldwide are exposed to degradation processes, which are continuously increasing at a rate of 5–7 million ha annually (Mabit et al., 2014). Furthermore, there are significant economic losses linked with soil erosion, as nutrient-rich topsoils are the most susceptible to erosion, resulting in the annual loss of 23–42 Mt N and 15–26 Mt of P from agricultural soils (Kopittke et al., 2019). Expensive land development technologies are not good alternatives because most damaged lands are in nations with economic shortages. In such conditions, annual and perennial legumes, which can thrive well in arid, low-nutrient, salty, alkaline, or acidic soils, are the best options among the current reclamation tools (Franco and Faria, 1997). Because of their diversity and greater adaptability, legumes may be grown in almost any climate or location on the globe. Soil fertility, nitrogen levels, and soil carbon content are all quite low in degraded fields. These can be established and maintained in these places by cultivating legumes, which require very little fertilizers and other inputs in return for adding significant amounts of nutrients (especially N) and organic matter to the soils.

1.10 Promoting soil properties and associated processes

Soil organic matter largely determines the maintenance and improvement of soil physical, chemical, and biological properties. Since green revolution major focus was given on cereal cropping that resulted in a decline in soil organic carbon. Legume cropping significantly improves the soil microbial biomass, various biochemical processes including nutrient cycling, mineralization, and thus helps to maintain the productivity and sustainability of production system (Deakin and Broughton, 2009). This is associated with deep relationship of leguminous plants with soil microbes with and consequently biochemical processes driven by them. Likewise, legumes acts as soil conditioner and improves the soil physical conditions through enhanced soil formation, soil profile, soil porosity, structure, and aggregation due to improved soil microbial activities and deposition of soil organic matter (Lithourgidis et al., 2011). Besides, generation of the considerable amount of organic matter, legume species release a good amount of NPK and other essential elements those remain available for succeeding crops.

1.11 Reduce ecological footprint and ensures climate-resilient agriculture

Legumes in the cropping system reduce ecological footprint owing to their reduced fertilizer requirement, less water requirement, carbon sequestration, ecological weed management, soil erosion prevention, and reduced labor and energy requirement. The reduction of synthetic N fertilizer application into agroecosystem is possible by the absence of nitrogen fertilizer to legumes and by limited application to the following crop (Cai et al., 2018). Besides, providing healthy, nutritious, and sustainable food, legumes offer multiples management ecological footprints including enhanced biodiversity at farmland, adaptation to climate change, soil carbon sequestration, and reduction of GHGs emissions into the atmosphere (Pikul et al., 2008).

1.12 Improved ecosystem services sustainably

The diverse and varied services to humans offered by the natural environment and healthy ecosystems are referred to as ecosystem services. A healthy ecosystem offers natural crop pollination, clean air, extreme weather mitigation, and human mental and physical well-being. These advantages are collectively known as ecosystem services, and they are typically critical to the provisioning of waste decomposition, as well as the productivity and resilience of food ecosystems. For the sake of safety and environmental effect, less inputs and reduced reliance on chemical fertilizers become critical. This necessitates the inclusion of legume species into cropping systems, including agroforestry. Legume crops protect the soil, water, and fossil resources owing to their fewer requirements upon inputs and other natural resources. The deeper root system and the phenomena of biological N fixation enable legume species to accelerate nutrient, carbon, energy and hydrological cycling in agroecosystem, forest ecosystem, and grassland ecosystem. These species had several rotational benefits to the component and subsequent crops that includes weed suppression, residual N, qualitative fodder, etc. (Pikul et al., 2008; Cai et al., 2018).

1.13 Conclusions

In intensive agriculture, cereal-based farming has substantial environmental risks in terms of loss of soil health and quality, falling crop and factor productivity, chemical residue deposition in soil systems, and a variety of other ecosystem services. This book has compiled the needs for sustainable intensification of crop production systems, although that requires a wide range of initiatives and efforts to build ecofriendly environment with the inclusion of legumes. Legumes are an important component crop owing to their several ecosystem benefits, hence must be an integral part of the farming system in the form of spatial or temporal integration in the system. Inclusion of legumes on the agroecosystem greatly reduces the pressure on natural resources, environmental services, and establishes systems with the potential to improve system productivity sustainably. For that, still we need to improve production of grain legumes by bringing more areas under legume cultivation in rice fallow, summer fallow, intercropping system and agroforestry systems. This book is focused to help for augmenting food production to fulfil demands of mounting populations as well as ensuring the sustainability of the agroecosystem. To accomplish this, the yield potential of grain legumes has to be increased through advanced technological intervention and agronomic management.

Acknowledgment

This work has been completed through financial support under the Institute of Eminence (IoE) scheme No. 6031, BHU, Varanasi (UP) – 221005, India.

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Chapter 2

Scope for production of pulses in rice fallow lands in South Asia

Ajay Kumar Mishraa,b, Pavan Kumar Yegginaa,b, Devi Dayal Sinhaa, Amit Kumar Srivastavab, Sheetal Sharmab

aInternational Rice Research Institute, Bhubaneswar, Odisha, India

bInternational Rice Research Institute South Asia Regional Centre (ISARC), Varanasi, Uttar Pradesh, India

2.1 Introduction

Food security is a significant challenge in South Asia despite of significant developments, it remains the world’s second poorest region with more than 500 million people living on less than US$ 1.25 a day (Bishwajit et al., 2013). Climate change, rapid population growth, urbanization accelerate the problem (Knox et al., 2012; Masters et al., 2013; Gerland et al., 2014). Meanwhile, existing arable land is intensified through monocropping and increasing use of pesticides and chemical fertilizers negatively affect the environment and its ecology (Liu et al., 2015). Globally, Asia has the highest concentration of poverty. Farming systems in Asian economic diets depend on a few commodities (Garnett et al., 2013), mainly rice (Oryza sativa) and wheat (Triticum aestivum). This dependency, alongside a lack of income to purchase sufficient and quality food, contributes to high under- and malnutrition rates in women and children. High infant, maternal morbidity, and mortality have been reported in India and Bangladesh (FAO, 2015a).

We need to increase and diversify food production to meet the increased nutritional demands growing population. Moreover, the export demands would provide additional income to smallholder farmers across South Asia. However, expanding the area to increase production or through technological means such as irrigation, fertilizer, and mechanization is limited due to increasing pressure on croplands for alternative uses as well as environmental concerns, production cost, and severe stresses on water availability in a changing climate scenario (Garnett et al., 2013). Many other factors, from climate change to urbanization to a lack of investment, also make it challenging to produce enough food. Hence, agronomists should consider cropland intensification and its diversification as an imperative and viable solution.

Rice fallow, a rainfed lowland agroecology, is presently picking up steam for sustainable cropping intensification in South Asia. In South Asia, approximately 22.3 M ha (million hectares) area is under rice fallow (Gumma et al., 2016). The rice fallow areas are mostly observed in the parts of Eastern India and account for ~84% (9.7 M ha) of the country’s total rice fallow area (11.7 M ha) (Ali et al., 2014; Singh et al., 2017a). Whereas, Gumma et al. (2016) reported a 19.6 M ha area under rice fallow in India.

Several challenges are being faced with introducing pulse crops in rice fallow areas, especially in eastern Indian states. The significant challenges are inadequate irrigation availability, residual moisture issues (lack/excess), manifold stresses (flood, drought, cyclone, heavy rains, waterlogging, temp extremes, and biotic stresses), cattle grazing, improper seed supply of short duration of rice varieties/high yielding of pulses, low farm mechanization and a big gap between farmer produce with the market link. The SWOT analysis offers insight on strengths, weaknesses, opportunities and threats in rice fallow management (Fig. 2.1).

Fig. 2.1 SWOT analysis of rice fallow areas in India (modified from Singh et al., 2016).

The sustainability of rice fallows in South Asia is stressed by soil quality degradation, declining groundwater resources, environmental pollution, and diminishing farm profitability (Kumar et al., 2020). This chapter highlights recent developments in identification, characterization, spatiotemporal analysis of residual soil moisture availability, mapping of abiotic stress areas, extrapolation domain maps for crop suitability. In addition, this study offers best bet strategies and innovative pathways for targeting rice fallow and a road map for accelerating intensification and diversification in South Asia. For targeting rice fallow, this study proposed a conceptual framework that needs to be implemented at different scale for efficient management of rice fallows (Fig. 2.2).

Fig. 2.2 Conceptual framework for rice fallow management in South Asia. This framework includes identification and mapping of rice fallow, stress environment identification, crop suitability mapping for intensification and diversification, networking and capacity development of different stakeholders for efficient management of rice fallows at a different scale.

2.2 Global scenario and constraints of rice fallow management

2.2.1 Global scenario

South Asia accounts for about 40% of the world’s harvested rice cultivation land (USDA 2010) and feeds almost 25% of the world’s population domestically and abroad (FAO, 2015b). Globally, there is enormous pressure to produce at least 50% more food to feed the projected world population of 9.15 billion by 2050 (Alexandratos and Bruinsma, 2012). India accounts for 79% (11.65 M ha) of South Asia’s total rice fallows (15.0 M ha). Rice fallows are mainly spread in Assam, Bihar, Andhra Pradesh, Chhattisgarh, Odisha Jharkhand, Madhya Pradesh, West Bengal, and Uttar Pradesh (Subbarao et al., 2001). Pande et al. (2012) reported the potential of pulse cultivation in Central and eastern India on rainfed rice fallow lands (Fig. 2.3). A recent study on satellite-based mapping of rice fallow area in South Asia estimated approximately 22.3 M ha suitable rice fallow spread in different countries, that is, 88.3% in India, 0.5% in Pakistan, 1.1% in Sri Lanka, 8.7% in Bangladesh, 1.4% in Nepal, and 0.02% in Bhutan (Table 2.1) (Gumma et al., 2016).

Fig. 2.3 Potential rainfed rice fallows for pulse cultivation in central and eastern India (adapted from Pande et al., 2012).

Table 2.1

Though India is the largest pulse producer (around 25% of global production), it consumes 27% and imports around 14% of its pulse’s requirements. The average yield of pulses in India is relatively low at 781 kg/ha, which might be due to policy neglect. The postgreen revolution era observed a sharp decline in per capita production and pulses availability, with a record 6.60 Mt imports of pulses in 2016–2017. The trend in imports of pulses is presented in Table 2.2

Table 2.2

2.2.2 Constraints in targeting rice fallow

Rice fallow areas are those kharif (summer) paddy grown areas that were kept fallow in the rabi (winter) season. The main reasons for leaving the lands fallow during the winter season are lack of irrigation, late harvesting of long duration high yielding rice varieties, moistures stress at sowing during the rabi crops due to early withdrawal of monsoon, waterlogging and excessive moistures in November/December, and nuisances like stray cattle and blue bulls (Ali and Kumar, 2009; Kumar et al., 2019). In addition to the above-mentioned constraints socioeconomic and several other productions, constraints are a predominant and crucial obstacle in implementing the crop in rabi season, aiming for targeting rice fallow. These key constraints may be categorized under abiotic, biotic, socioeconomic, and other production constraints (Fig. 2.4).

Fig. 2.4 Major constraints in targeting rice fallow in South Asia.

2.2.2.1 Abiotic constraints

Abiotic constraints are related to physical stress that is most often associated with soil moisture stress, marginal soils with low fertility status, problematic soils, and unpredictable environmental conditions prevailing at sowing. The abiotic constraints cause lower pulse production. Exposure to heat stress during flowering and pod filling stages adversely affects pulses productivity and reduces output up to 50% of potential yields.

Under problematic soils, soil salinity and alkalinity restrict the growth of pulses. In contrast, other like unfavorable low pH, that is, soil acidity is the major problem in eastern India, soil salinity and alkalinity, on the other hand, are of most significant concern in lower and middle Gangetic plains. An unfavorable and consistently deteriorated soil physicochemical condition following rice (mostly grown under puddled or flooded conditions) restricts the pulses (as these favors upland conditions). The situation is further aggravated, causing a decline in pulses growth and yield due to lesser availability of nutrients, low microbial (rhizobium) activity, and limited root growth. Inherent constraints of same crop cultivation also affect pulses seed germination and seedling emergence and establishment due to disruption in soil structure, soil water deficit, poor aeration, and mechanical impedance rhizospheric zone. The hardness of soil in the puddled rice fields also deteriorates soil hydraulic properties that adversely affect the soil moisture distribution and root growth of deep tap-rooted pulses. As a result, subsoil resources in rice fallow areas remain unutilized. The relay (paira) cropping system may reduce the number of conflicts, but its plant population is often low because of low seed germination due to poor seed-soil contact, seed or seedling rotting (due to high soil moisture and anaerobic condition) as well as drying (due to undulated dry soil mostly seen in patches). If tillage is taken up after rice harvest to remove stubbles, sowing of rabi pulses gets delayed and germination will also be hampered due to the formation of large size clods and soil moisture gets depleted soon.

2.2.2.2 Biotic constraints

Due to prevailing anaerobic conditions in rice cultivation, many organisms, including rhizobia, could not thrive well under such a situation. Even if the crop is sown timely and established well, it often reports a high incidence of insect pests and diseases. Although detailed studies on the dynamics of disease pests in pulses in rice fallow areas have not been well taken up, these biotic agents thrive well under such a situation to cause visible damages afterward (Singh et al., 2017b). Evidence suggests that pulses are the most preferred host for insects. In chickpea (Cicer arietinum), the pests (particularly Helicoverpa armigera or pod borer) are reported to ring alarm as a potential threat to Chhattisgarh, Jharkhand, and Madhya Pradesh (Singh et al., 2017a).

Similarly, diseases such as powdery mildew, mung bean yellow mosaic virus (YMV) diseases and several dry/wet rots and wilts are considered serious problems (Singh et al., 2017a). Powdery mildew is another severe disease of rabi planted black gram (Vigna mungo) and mung bean (Vigna radiata) in coastal belts due to higher relative humidity. Similarly, rust and Fusarium wilt are commonly found in lentils (Lens culinaris) (Singh et al., 2017c). However, black gram and mung bean are susceptible to yellow mosaic virus, powdery mildew, Cercospora leaf spot, and leaf curl virus. Most of the time, in the absence of resistant varieties and specific awareness as in Odisha and West Bengal and parts of Bihar, Chhattisgarh, and Jharkhand (where pulses area is small and scattered, which may be attributed to lack of land consolidation), these biotic constraints put a hold to potential productivity of these so-called manageable fertile lands (Singh et al., 2017a). Unavailability of pesticides in adequate quantity and at the right time is also a critical hindrance to profitable pulses cultivation. Like insects and pests, weeds are also a menace for pulses under rice fallows as this cause around 50% average crop loss if kept uncontrolled (Singh et al., 2017a). Ratooning of rice after harvesting is another major problem in rice fallow relay system in many parts of the country (causing pests’ resurgence, uncontrolled weeds and deteriorated soil physical–chemical condition), which needs particular attention so far, its (rice ratoon) scientific management is concerned (Singh et al., 2017a).

2.2.2.3 Socioeconomic constraints

Lower economic conditions and less purchasing capability induce farmers to leave fields unused after the rice harvest. Besides, fragmented land holding, shortage of labor, nonavailability of inputs, cattle grazing, limited access to institutional credit, lack of market, lack of knowledge among farmers on water-conservation techniques, poor extension service directly or indirectly discourages the farmers from taking winter or second crop (Joshi et al., 2002).

2.2.2.4 Other production constraints in managing rice fallow

Several other production constraints affect the farmer’s decision on considering crops after kharif. Some of them are listed below.

2.2.2.5 Soil moisture depletion and lack of irrigation

Although in rice—the fallow area gets normal to high rainfall during rice (kharif) season, most rainwater is lost due to soils’ high runoff and low moisture storage capacity. After puddle rice, soil compaction restricts water infiltration, development of deep and wide cracks in the soils after rice harvest helps in the fast depletion of stored soil moisture through evaporation. Low soil moisture during sowing of fallow crops results in poor plant stand (Kumar et al., 2018). If the crop is established well with residual soil moisture, the lack of winter rains toward the reproductive stage often leads to complete failure of the crops (Ghosh et al., 2016). Available soil moisture gets exhausted before the crop reaches the flowering stage, resulting in terminal drought and heat stress (Kumar et al., 2018).

2.2.2.6 Shortage of quality seeds of pulses

Lack of quality seeds of short-duration varieties of pulses for rice fallows is also one of the significant constraints (Mishra and Kumar, 2018).

2.2.2.7 Long duration rice varieties

In rice fallows areas, farmers used to grow the lengthy duration rice varieties and it matures in 160–165 days, so delayed in sowing of subsequent pulses, resulting in low yields due to terminal drought. More than 90% of farmers viewed the lack of suitable crop varieties as the main bottleneck in rice fallows (Pandey et al., 2012).

2.2.2.8 Poor crop management

In the rice fallow area, the winter crops are considered bonus cropping (Ali and Kumar, 2009). Because of risk concerned for growing the winter crops due to limitation of soil-moistures as well socioeconomic hindrance, the farmers do not give more attention to crop management, that is, selection of suitable cultivars, seeding rate, crop protection, Rhizobial treatment, foliar feeding of nutrition and farm mechanization (Singh et al., 2017a).

2.3 Strategies and innovative pathway for targeting rice fallow

Pulses are grown mainly in similar agroecologies and are considered companion crops for mitigating adverse weather conditions. Pulses have an additional advantage of their soil-enriching capabilities and supplement good quality fodder in rice fallow areas (Kumar et al., 2019). Critical interventions, that is, demonstration of improved production technologies with cluster approach, augmenting the availability of quality seed, seed priming and treatment with Rhizobium/fungicide, application of micronutrients, insect pest management and lifesaving irrigation, will be supported for visible impacts in rice fallows (Kumar et al., 2019). Resource conservation technologies (RCTs) may be a suitable approach to tackle exertion in rice fallows areas. Zero till (ZT) with minimum disturbance of the soil and retaining crop residues might be favorable impacts on inherent soil property that further enhance overall productivity in rice fallows. It helps to reduce the cost of cultivation and improve input-use efficiency. Fodder scarcity for livestock during rabi is also an essential issue in rice fallows. Intensification of rice fallows may help to meet our fodder requirement during the lean period. Simple technologies like seed priming, spraying of 2% urea and di-ammonium phosphate (DAP) and micronutrient at vegetative stages help sustain soil and produce more at low cost for resources-poor farmers (Kumar et al., 2019).

2.3.1 Water harvesting and storage

Despite heavy rain in kharif (rainy season), moisture becomes the foremost restrictive factor for taking the second crop in rabi (winter season) as most overflow is washed out. Thus, it is essential to make available arable farm ponds and community water reservoirs in such areas with governmental agencies’ support. It will provide a vital means for life-saving irrigations for rabi crops (Kumar et al., 2019). To get optimum rice fallows’ optimum productivity, it is necessary to have proper soil moistures at sowing and water facility for at least one life-saving/supplemental irrigation at the most critical stages (Kumar et al., 2019). Since plenty of water is lost during the rainy season through runoff, there is a need to harvest this excess rainwater and store it in small farm ponds or reservoirs to provide life–saving irrigation to succeeding fallow crops. Construction of farm-pond or community water reservoirs to harvest excess rainwater during the rainy season is a feasible strategy to provide life-saving irrigation in rabi season; pulse crops in the rice fallows will help to increase the overall land productivity (Kumar et al., 2019). In north-eastern hilly (NEH) states with higher rainfall, technological options have been identified for two contrasting conditions of abiotic stresses, that is, excess soil moisture at rice harvesting in land-locked areas and valleys of the hill and fast depleting the soil moisture in upland, terraces and plains (Das et al., 2012; 2014).

2.3.2 Use of resource conservation technologies

Resource conservation technologies (RCTs) such as ZT/RT, retention of rice crop residue/mulching at 5 t/ha or 30–40 cm stubble has been noticed effective in the soil moisture conservation and increasing the crop yields and monitory returns in rice fallows. Reduced tillage has reported the increased yield of pulses like lathyrus (Lathyrus sativus), green gram, black gram, field pea (Pisum sativum) by 33–44% over conventional tillage (Kar and Kumar, 2009). Similarly, retention of rice stubble/mulching and ZT sowing of pulses significantly enhanced pulses productivity in rice fallows (Ghosh et al., 2016). Retaining 30% rice residues on the soil surface and ZT sowing with Happy Seeder increased lentil and chickpea yield by 3.1, and 11.7%, respectively (Unpublished results, CRP on CA Project at ICAR RCER, Patna). Similarly, utera cropping performed better than ZT (with or without mulch) and produced the maximum seed yield due to the advantage of early sowing for better utilization of residual soil moistures. Lathyrus followed by linseed (Linum usitatissimum) and lentil among different crops put down the maximum yields and profits (Mishra et al., 2016). In rice fallows, ZT after rice harvest timely planting facilitates winter pulses and helps escape adverse effects of terminal drought and rising temperature in spring-summer. Trials results with the farmers participatory on ZT lentil and chickpea in Eastern IGPs during 2009–2010 showed that using ZT with reduced seed rate (30 kg/ha for lentil and 80–100 kg/ha for chickpea), deeper seed placement (5–6 cm for lentil) improved crop establishment, crop productivity, and reduced wilts incidence (Singh et al., 2012). An adoption survey was conducted on farmers’ participatory on ZT seeded lentils in rice fallows (200 ha) of Nawada, Bihar showed that ZT planting of lentils together with the suitable improved agronomic packages resulted in higher yields (13%) and a reduced cultivation cost by 3800 ha−1, thereby increasing farm profitability of 10,000 ha−1 (Singh et al., 2012). Drivers of resource conservation technologies are mentioned in Fig. 2.5.

Fig. 2.5 Various components of resource conservation technologies (RCTs).

In lowlands having high moistures after rice harvest, draining excess water at physiological maturity of rice by providing drainage channels at appropriate intervals creates a favorable soil condition for ZT for rabi pulse (Layek et al., 2014). However, in dry soil at rice harvest, NT and standing stubbles/residue retention @ 5 t/ha and life-saving irrigations could give reasonable lentil yields (Das et al., 2012). Paddy straw mulching/water hyacinth (Eichhornia crassipes) increases groundnut (Arachis hypogea) sown productivity after rice harvest (Chaudhary et al., 2014). ZT drill for small farmers developed by Indian Institutes of Pulse Research Kanpur, for line sowing in rice fallow, which helps in moisture retention and least disturbances of soil occurs. At several locations in IGPs, the experience showed that ZT farmers save on the preparatory operation by INR 2500 ha−1 and reduced diesel of 50–60 L/ha (Sharma et al., 2005).

2.3.3 A system model of crop production

For efficient utilization of soil moistures and maximizing rice fallows’ system productivity, long-duration rice varieties need to be replaced with short to medium duration varieties for early harvesting and timely sowing of succeeding crops. Where seeds are broadcasted in paira/utera (relay) cropping method in standing rice 10–12 days before crop harvest, rice fields need to be appropriately leveled for maintaining uniform soil moisture to facilitate uniform seed germination.

2.3.4 Suitable crops and varieties

Due to the lack of accessibility of the superior seed, it is an important limitation for late sowing and reduced winter crop yield in rice fallow. Therefore, a community-based seed multiplication plan should be managed with appropriate dissemination and storage facilities. Growing early to medium-duration rice varieties (Prabhat, Naveen, Swarna Shreya) certainly helps the farmers advance the sowing of succeeding crops to utilize available soil moistures. Residual soil moisture in the soil after harvesting rice is often sufficient to support short-duration crops. In India’s eastern states, short-duration varieties of pulses like lentil, lathyrus, chickpea, field peas, mung bean, and black gram could be cultivated profitably in rice fallows under ZT or utera (Table 2.3). Lentil and Lathyrus can be grown successfully by utera cropping in low land areas with residual soil moisture, and small-seeded pulses varieties are better than large-seeded (Table 2.3).

Table 2.3

Among the winter crops, safflower (Carthamus tinctorius) was most remunerative to the farmers followed, by the black gram, lentil, mustard (Brassica spp.) and, Niger (Guizotia abyssinica) in rainfed condition. Safflower is the most remunerative crop in rice fallow rice fallow (Kar and Kumar, 2009). Extensive trapping of the rice fallows need short-duration pulses varieties that can efficiently avoid terminal drought. Pulses genotype with a fast-growing and comprehensive canopy coverage can minimize the evaporation losses, which depletes soil moisture rapidly (Kumar et al., 2019). For utilizing residual moistures efficiently, early to medium-duration rice varieties enable the farmers to advance the sowing of pulses are to be grown; thus, there is an urgent need to develop an extra early-duration cultivar pulse for fallows areas (Mishra and Kumar, 2018). Data on the effect of pulse varieties with improved management practices are presented in Fig. 2.6.

Fig. 2.6 Yield of pulses (green gram and black gram) under different crop management practices in Khordha district, Odisha (annual report 2018–2019).

2.3.5 Seed priming and optimum seeding rate

Seed priming is a vital cost-effective technology for improved crop and increased yields of pulses in rice fallows (Ali et al., 2005). Overnight seeds are soaked with water or nutrient solution before sowing, known as seed priming, a significant low-cost technology to improve germination and seedling emergence. It may be recommended to increase the seed rate by 20–25% to have the desired plant population in rice fallows (Bhowmick et al., 2005). Rautaray (2008) reported that for some particular areas that fallow after the aman rice, agronomic manipulation under the rice-utera system could increase the cropping intensity. Solaimalai and Subburamu (2004) reported that soaking of seeds with (potassium dihydrogen phosphate) KH2PO4/(monosodium phosphate) Na2HPO4/water before planting improves the seed germination, seedling vigor, and root growth early, resulting in the excellent establishment, better drought tolerance and, more crop yield. A field trial was conducted at Pulses and Oilseeds Research Station, Murshidabad, West Bengal, during rabi season to evaluate the different levels of seed priming (water soaking, 2% KH2PO4 solution and sprouted seeds) along with varying levels of foliar nutrition (water spray, 2% urea/DAP/KCl spray) using crop lathyrus cv. Ratan (Bhowmick et al., 2014). Results showed that sprouted seeds had the highest seed yield (1021 kg/ha), followed by seed soaking in 2% KH2PO4 (964 kg/ha). Bhowmick et al. (2014) reported that the planting of the primed seed, either sprouted or 2% KH2PO4 soaked, followed by foliar application of 2% urea/DAP. once at the preflowering stage and second after 10 days would be a potential cost-effective technique for augmenting the production of lathyrus under utera cropping in the rice fallows.

2.3.6 Seed treatment and foliar plant nutrition

Pulses seed should be treated with fungicides followed by rhizobium, phosphate solubilizing bacteria (PSB) and vesicular-arbuscular mycorrhizae (VAM) fungi and trichoderma inoculation before sowing, helps in disease-free plant and better nodulation. The application of fertilizer to soil often leads to locking/loss of nutrients; foliar nutrition may be a better option in such conditions. Bhowmick et al. (2014) reported; the need for fertilizer may be curtailed by making the availability of nutrients to the kitchen of the plant directly, thus, leaving no wastage. Foliar spraying of KNO3/Ca (NO3)2 at 0.5% significantly improved pulses yield (Sarkar and Malik, 2001; Layek et al., 2014), Bhowmick et al. (2014) reported among the foliar sprays that application of 2% urea at preflowering stages had the maximum seed yield (1040 kg/ha) and followed by 2% DAP spray (983 kg/ha). Besides the moisture stress, winter crops in rice fallow experience several nutrient stress levels. Ali et al. (2014) reported that because of the soil’s poor physical condition and low native Rhizobium in typical rice fallows nutrient mobilization is substantially reduced. According to Kumar et al. (2016), deficiency of micronutrients is also widespread and supplementary application of these inputs, especially Mo, is necessary for acidic soil of rice fallows. In acid soils, the application of lime/seed priming with Mo was most effective.

2.3.7 Pest and disease management

In rice fallow areas, diseases, namely root rot, powdery mildew, yellow mosaic and insects like pod borer, cause heavy damage to pulse crops. Integrated pest management (IPM) strategy to manage insect-pest and diseases, involving seed treatment with fungicides and biocontrol agent Trichoderma, selecting disease tolerant varieties and spraying need-based fungicides/insecticides will be useful. After integrated pest management like bird perches, we may consider a spray of NPV/chemical pesticides useful for controlling the pod borer in pulses crop. Small-sized lentils (WBL-77, KLS-21, NM-1, and DPL-15) have resistance to rusts in eastern India. For checkout seed-borne diseases, seed treatment with suitable fungicides/insecticides/plant growth-promoting Rhizobacteria is required. Seed treatment with Trichoderma + carboxin/alternately carbendazim + thiram for root rot, color rots/wilt in chickpea, lentil, mung bean/black gram is observed useful for pulse production (Table 2.4).

Table 2.4

*Yield is for the second crop; #GWP-global warming potential of the cropping system.

2.3.8 Weed management

Kumar et al. (2016) reported that similarly, integrated weed management (IWM) strategies include crop residue mulching, ZT sowing, application of postemergence herbicides for grassy weed control and, need-based manual weeding should be adopted. In rice fallows, effective postemergence herbicides are not accessible. Intercultural operations are additionally troublesome, as upper soil layers turn out to be hard. So, hand-weeding is the primary choice that must be made at the early stages of crop growth (Ali et al., 2014). Singh et al. (2017a) reported that suitable postemergence herbicides are unavailable for pulses and carrying out intercultural operations is challenging due to soil compactness; manual weeding is only completed initial stages of crops. Use of imazethapyr @ 100 g/ha has been observed relatively efficient in pulses (groundnut/urd bean/mung bean) at initial stages of crop growth against the narrow-leaved weeds (Ali et al., 2014). According to Kumar et al. (2018), glyphosate/paraquat application to check rice stubbles’ growth causes significant moisture losses in rice fallows are required before sowing winter crops. Application of quizalofop @ 50 g/ha at 15–20 days after sowing (DAS) has also been seen as useful in checking the regrowth of rice and the grassy weeds (Kumar et al., 2016).

2.3.9 Soil moisture retention and conservation

Effective moisture conservation practice can mitigate the moisture-related stress and terminal drought in rice fallows. The approaches of RCTs prevent rapid soil moisture losses (Karet al.,2004), improve SOC and biophysical properties (Gangwaret al., 2006) may be strategic approaches in rice fallows (Ali et al., 2014). Pulses need to be sown immediately after rice harvest to utilize the residual soil moisture: ZT checks soil moisture loss and advances planting by 7 days (Mishra et al., 2016). RT increases pulses (lathyrus/lentil/chickpea) yield by ~33–44% over CT in rice fallow (Kar and Kumar, 2009). It is also confirmed that the moisture-conservation potential of RT is better than NT/relay cropping. Similarly, RT gives a higher yield of pulses (Ghosh et al., 2010).

2.3.10 Crop establishment techniques

Mishra et al. (2016) reported the performance of three winter pulses, viz., lathyrus (Ratna), chickpea (JG-14), and lentil (HUL-57) were evaluated under ZT and ZT with straw mulch @ 5 t/ha (ZTM). Results showed that ZTM was recorded to increase the yields of pulses. A long-term field experiment initiated by Kumar et al. (2018) and results showed that ZT-DSR had maximum rice yield (5.14 t/ha) followed by CT–TPR (5.05 t/ha). In general, the productivity of succeeding crops was observed higher after ZT-DSR. In rabi crops, chickpea (1559 kg/ha), lentil (1515 kg/ha), and safflower (1761 kg/ha) out yielded in ZT-DSR than that to UPTR and CT-puddle. Productivity was reported higher with chickpea (5799 kg/ha), lentil (5408 kg/ha), and safflower (5325 kg/ha). To get a better yield of winter crops in rice fallows, conserving soil moistures in the conventional systems through increasing stubbles height should be followed. Kar and Kumar (2009) reported higher pulses yields after paddy harvesting in R.T. Blanco-Canqui and Lal (2008) report incorporating residues/retaining residues on the soil surface have numerous benefits on soil excellence. Retaining crop residue on soil surfaces may be a good option than incorporating it as it reduces erosion and evaporation, evading the short-term association of nutrition and suppressing weeds. Marginal and small land holders in budding countries like India are facing by way of trading-off in manage residues. Residues are separated for biofuel, or farm animals feed or graze (Ghosh et al., 2010). The residue has high values and still little quantity is retained after harvest, increasing over year and change in farmer to manage residues since a durable asset on soil qualities (Das et al., 2018). According to Layek et al. (2014), the information on residue retentions coupled with appropriate sowing like utera helps mitigate terminal drought in pulses by protecting soil moisture and sinking evaporation in these fallows. Therefore, cost-effective conservation tillage and resilient cropping are feasible options to growing options, lathyrus and chickpea in rice fallow area. Therefore, the paddy transplant at the right timing with short-duration varieties might sustain the moisture deficits and terminal drought. Cutforth and McConkey (1997) reported that the retaining paddy stubble of dissimilar habit possibly would modify features soil surface and influence soil’s thermal property by sinking evaporations, which render additional water available to the crops.

2.4 Geospatial technology targeting the rice fallow lands: A case study of Odisha

2.4.1 Identification and characterization of the potential rice fallow areas

To achieve this objective, time-series high-resolution Sentinel-2 satellite data is used to suggest suitable cropping patterns for fallows and rice fallow lands. The European Space Agency (EPA) has developed and launched the Sentinel-2 satellite in June 2015. Sentinel-2 satellite consists of Multispectral Imager (MSI) 13 spectral bands out of which four bands at 10 m, six bands at 20 m, and three bands at 60 m spatial resolution.

2.4.2 Identifying rice fallows in Odisha for targeting water-efficient pulse crops

The spatial distribution of seasonal cropping pattern extracted using the integrated analysis of Landsat OLI (multispectral) + Sentinel-1 (SAR) data during 2015–2016, 2016–2017, and 2017–2018 revealed that approximately 2 m ha area remains fallow in rabi season after kharif rice crop in the state of Odisha (IRRI Odisha Annual Report 2017–2018, 2018–2019, and 2019–2020; Fig. 2.7). The majority of the double-crop system is concentrated in coastal districts (Jagatsinghpur, Ganjam, Puri, Jajpur, and Kendrapara district). Moreover, few double-crop system patches can be observed in Kalahandi, Bargarh, Sambalpur, Sonepur, Baleswar, and Koraput districts. Whereas, the maximum focus of rice fallow areas is observed in Mayurbhanj, lowland areas (especially in Rasulpur, Dharmasala, Jajpur, and Bari block) and Puri (Brahmagiri block) districts where land remained immersed in water in Monsoon season and allow farmers to grow crops only in rabi season after receding of water.

Fig. 2.7 Temporal and seasonal cropping pattern and spatial distribution of rice fallow areas.

The overall kharif-fallow area in Odisha during 2015–2016, 2016–2017, and 2017–2018 crop calendar are 2.20, 1.97, and 2.12 m ha, respectively. Out of 30 districts, 9 districts, that is, Mayurbhanj, Keonjhar, Bargarh, Balangir, Sundargard, Bhadrak, Nawarangpur, Keonjhar, Anugul district.

2.4.3 Rice fallow frequency in Odisha

The extracted rice fallow area was used to make a rice fallow frequency map, which provides three frequency occurrences with seven categories. The rice fallow area with triple frequency is estimated at 1.34 M ha under permanent rice fallow.

About 50% of the total triple frequency rice fallow area can be observed in Mayurbhanj (9.5%), Bhadrak (7.1%), Bolangir (7.1%), Sundargarh (6.4%), Keonjhar