Climate-Resilient Technologies for Enhancing Productivity of Soybean in India

Abstract

Soybean (Glycine max [L.]) contributes 25% of the global edible oil. Globally, soybean area and production in 2020 were 127.9 million ha and 379.8 million tons, respectively. Soybean has got early acceptance as an important oilseed crop in India in with approximately 10–11 million ha area. Now, it has become a major crop by replacing the traditional and contemporary popular crops in nearly all parts of India. Climate change effects, like change in Monsoon pattern, increase in dry spell frequencies, heavy rainfall event during crop growth period, extended monsoon at harvesting stage, has drastically influenced the productivity of soybean, which needs attention to identify the constraints and accordingly adapt the climate-resilient technologies. The recent research conclusions revealed that the climate-resilient technologies like selecting suitable varieties, sowing within proper sowing window, broad bed furrow (BBF) method of sowing, dry spell management practices to reduce moisture stress, rainwater harvesting, and soil conservation through BBF method of planting, reuse of harvested and stored rainwater during moisture stress conditions, the adaptation of micro-irrigations systems for protective irrigation, intercropping in soybean, resource conservation techniques can mitigate the effects of climate change and enhance the productivity of soybean in a sustainable manner.

1. Introduction

Soybean cultivation and its use was started from the beginning of Chinas agriculture age. Its utilization for human consumption was mentioned [1] long ago 6000 years back in Chinese medical compilations. Soybean has meant for milk, meat, bread, cheese and oil from centuries ago to common people of China, Korea, Manchuria, Japan, Philippines and Indonesia. The center for origin of soybean is China while some reports second center as India [2, 3, 4]. In India initially, soybean has been traditionally grown in patches of the Kumaon Hills of Uttarakhand (earlier Uttar Pradesh), the Khasi Hills, the Naga Hills, Manipur, Himachal Pradesh, and parts of central India encompassing Madhya Pradesh.

During 2020 the global area and production of soybean was 127.9 million ha and 379.8 million tons respectively. India stands fifth rank in the area and production in the world after countries USA, Brazil, Argentina and China. The productivity of soybean in India is low (1.1 tons/ha) as compared to the world (2.3 tons/ha).

Rainfed agriculture produces much of the food consumed globally. It accounts for more than 95% of farmed land in Sub-Saharan Africa, 90% in Latin America, 65% in East Asia and 60% in South Asia. The rainfed agriculture across the world is being affected by climate change.

1.1 Indian situation

On global map India lies between 8° N and 37°. In all climate over Indian subcontinent is dominantly tropical except Northern parts where the climate is temperate. Climate over India is characterized with distinct hot and dry climate altered with wet and humid climate in cyclic pattern. This is due to monsoon winds. Typical monsoon over India has two branches, i.e., Arabian sea branch and Bay of Bengal branch.

In Indian context soybean has occupied the position as major crop of India by replacing the traditionally grown major region-specific contemporary crops like cotton, paddy, and wheat. This has derived the agriculture completely new cropping systems also. Reasons of early popularity of the soybean crop in India are good demand of crop in international market, assured economic value of the crop along with the nutrient rich in both oil content (16–21%) and protein content (36–42%). Climatic requirements of soybean crop in more or less variations matches with existing climatic conditions over India which may be one of the reasons for steady performance of soybean in terms of production and productivity.

Based on productivity levels of soybean, total Indian geographical area is categorized in six agroclimatic zones which are Northern Hill Zone, Northern Plain Zone, Eastern Zone, North Eastern Hill Zone, Central Zone, and Southern Zone. The breeding for improving varieties with suitability and management practices specific to the particular zone are identified to achieve higher levels of productivity. In last years the area under soybean in India is constantly increasing with increase in productivity. In year 2020–2021 among various soybean growing states of India, Madhya Pradesh followed by Maharashtra were the first two states to grow soybean on 5.85 million ha and 4.32 million ha area respectively. In other states like Karnataka, Telangana, Gujarat, and Chhattisgarh there is considerable scope for the area enlargement (Table 1).

Sr. no.	State	Sowing area (ha)	Expected yield (kg/ha)	Estimated production (100,000 million tons)
1	Rajasthan	9.25	761	7.05
2	Madhya Pradesh	55.69	939	52.29
3	Maharashtra	43.85	1102	48.32
4	Chattisgarh	051	910	0.46
5	Gujrat	2.237	1015	2271
6	Karnataka	3.827	1005	3846
7	Others	1.129	975	1101
8	Telangana	3.488	1015	3540
Total		119.982	991	118.888

Table 1.

State-wise expected area, production, and productivity of soybean 2021.

Source: From [5].

The average annual rainfall of India is 1192 mm, with spatial and temporal variability which delineate the Indian agriculture in to dry farming, dryland farming and rainfed farming. The major soil types of India are Vertisols, Inceptisols and Entisols. Vertisols are deep black cotton soils having swelling and shrinkage properties, good water holding capacity. In India soybean is promising and prominent rainfed crop where seasonal rainfall is 900 mm and soil type is vertisols. In some parts of India traditionally adopted cropping system was Kharif fallow followed by post-rainy wheat or chick pea, but soybean has substituted this cropping system as soybean followed by wheat or chick pea. Gain in the kharif season crop has bring out improvement of small and marginal farmers profitability, socio-economic condition. The small and marginal farmers are subjected to subsistence farming due to limited production inputs. Even under aberrant weather conditions soybean has maintained its steady performance in terms of profitable returns to farmers [5].

Indian Council of Agricultural Research—Indian Institute of Soybean Research, at Indore, Madhya Pradesh was established to provide centralized research to support soybean production system research with basic technology and breeding material. Under AICRPS (All India Coordinated Research Project on Soybean) system 102 improved soybean varieties have been developed which were suitable to different agroclimatic zones, and promising with high yields due to tolerance to various biotic and abiotic stresses.

After independence through green revolution, high yielding varieties, India achieved record breaking/higher food grain production and achieved self-sufficiency in cereals production. This achievement of the higher production was associated with several extensive problems which encounter to degradation of the natural resources and challenged sustainability. The concepts of conservation have gained importance due to the threat of resource degradation problems, the necessity to reduce production costs, increase productivity and profitability and make agriculture more inexpensive. Over exploitation of natural resources, conducive to unsustainable growth; these strategies need to change in coming years for increasing the sustainability. For Indian agriculture it is the time where it must search for new guidelines—may be through strategies, policies, and actions which must be accepted to move toward sustainability.

In recent past decades, at global level, rapid moves have been made in order to develop and spread the technologies which will conserve resources. Conservation of soil and rainwater can be achieved with change in land configuration, and method of planting like broad bed method of sowing, minimizing soil disturbance through restricted tillage. Adoption of conservation agriculture (CA) include the basic three pillars or principles which are

1. Minimum soil disturbance

2. Crop rotations

3. Permanent soil cover (through cover crops, crop residues)

These principles can be effective possible ways towards the realization of the sustainability in agriculture and will help in achieving the goals of increasing productivity with prevention of further degradation of natural resources. To sustain soil fertility, improving fertilizer/water use efficiency, physical properties of soil, and enhanced crop productivity, techniques of crop residues retention on the soil surface, organic and inorganic combined fertilization and involvement of legumes in crop rotation are essential. Above techniques coupled with minimum or no-tillage practices play a major role in conservation of natural resources. Thus, resource- conserving technologies can be used to enhance soil health, water, and nutrient use efficiency.

2. Constraints responsible for low productivity of soybean in India

The national and regional yield or productivity levels are low as compared to global level. There are many limiting factors responsible for low productivity which are the gap in genetic and breeding for variety improvement, gap in management practices, post-harvest handling, and socio-economic factors. One or more than one limiting factor will aggravate the adverse effect on productivity, which is commonly observed in dryland farming areas.

1. Genetic and breeding for variety improvement,

   1. Inherent poor seed longevity,

   2. cultivation of single variety on large area mono-variety

   3. shattering losses due to delayed harvesting,

2. Inappropriate management practices

   1. Cultivation of soybean crop under rainfed condition.

   2. sowing under delayed conditions (after sowing window).

   3. Non application of seed treatment and inoculation at the time of sowing.

   4. No/little use of organic manures

   5. mixed sowing of seed with fertilizers

   6. Low or excess population of plant per hectare

   7. Imbalanced and improper fertilizer application

   8. Inefficient water management practices,

   9. Lack of proper insects and pests control measures

   10. Disproportionate use of water in spraying of pesticides,

3. Post-harvest handling

   1. Proneness of soybean to field weathering

   2. Storage of soybean at higher seed moisture content can reduce the quality of seed for its use as seed material for sowing and may result in low or no germination of seeds

   3. Mechanical harvesting of soybean more than 450 RPM speed of thresher will adversely affect the seed germination.

4. Socio-economic factors

   1. Timely unavailability of quality inputs,

   2. Poor coping techniques,

   3. Unavailability of credit loans to farmers at the time of sowing.

3. Climate resilient soybean production technology

3.1 Selection of field

Soybean production is remunerative when it is cultivated on a well-drained, sandy loam to clay soils. Soils with medium available water holding capacity and reasonable depth, can also be suitable for soybean. It requires soil with comparatively rich in organic carbon content. Neutral pH is ideal for harnessing maximum yield of soybean. The soil with excessive salts/sodium and poor drainage conditions are not appropriate for cultivation of soybean due to inhibition of seed germination.

3.2 Requirement of tillage

One summer ploughing followed by two cross cultivation or harrowing for breaking of soil clods or one deep ploughing once in 2–3 years can prepare perfect seedbed for a good growth and yield of soybean. It is the need of time to adopt minimum and conservation tillage (CT) to attain sustainability in soybean production.

3.3 Moisture conservation through land management

Soybean is cultivated majorly on medium to heavy soils and in Indian context, it is cultivated as major crop in rainfed areas which are associated with the dominance of vertisol soils. The rainfed areas of India are having the variation in rainfall distribution and its frequency. Extreme events like incidence of nearly 50% of seasonal rainfall in 2–3 rainy days are also recorded in many places in rainfed areas. As the Vertisol soils are high in clay content and their characteristic feature of swelling and shrinkage associated with slow infiltration rate, in such extreme events, they are prone to heavy runoff losses. The loss of rainwater not only removes soil nutrients but also its availability for utilization by crop toward its growth over season is also lost. This situation demands the essentiality for in situ soil and water conservation. Also, safe removal of excess water from the field is essential under water stagnation conditions. For attaining good drainage and in situ soil and water conservation land lay outs can be altered to achieve these objectives, which are as below.

1. Conservation furrows

   Under heavy rainfall events, to conserve moisture and draining out excess water from the field, can be achieved by a very simple technique of opening conservation furrows after every 4/6 rows of soybean.

2. Broad bed and furrow

   Broad bed and furrow (BBF) systems have been found to agreeably attain both the objectives specially in deep vertisols.

3.4 Selection of suitable variety

A good soybean variety should be high-yielding and should exhibit stable performance across abiotic and biotic stresses during crop growth. Growing more than one (preferably three to four) variety with different maturity durations is most advisable particularly when the planting area is on quite a large area to achieve sustainability in soybean production and to make efficient use of harvesting equipment and laborer.

3.5 Sowing window

In the northern, northeast, northwest, and central region of India, soybean is mostly cultivated as the sole crop in Kharif (June–October). But, in the peninsular and the North– Eastern region of the country, successful soybean cultivation is also feasible during rabi/spring and summer seasons (November–April). In Maharashtra also the area under cultivation of spring and summer soybean is increasing. Two successive seasons of soybean cultivation is not scientifically recommended due to the recent outbreak of pest and diseases.

During Kharif season, under irrigated conditions, one presoaking irrigation in the second fortnight of June is given for pre-monsoon sowing of soybean which has been found to give optimum plant population, good growth and high yields. When irrigation is not available, sowing should be done after the commencement of monsoon rains. Sowing should be started only after receipt of minimum 100–150 mm rainfall (depending on soil type) to avoid initial crop failure due to moisture stress or dry spell immediately after sowing. The date of onset of Monsoon varies in various parts of country. Appropriate sowing window for Kharif soybean is in between the third week of June to the second week of July (as per the commencement of monsoon). Timely sowing is very important non monitory input. Late planting leads to manifold problems like a poor plant population, reduced vegetative growth, reproductive efficiency, pod development, and yield. Sowing of Kharif soybean after 20th July is not recommended.

3.6 Optimum plant population

Optimum plant population is prerequisite for higher yields. Per plant yield contributing characteristics are in good quantity when the optimum plant population is maintained. One of the reasons for poor soybean yield in India is the sub-or super-optimal plant population. A plant population of about 450 thousand is optimum with a range of 400–600 thousand plants per hectare. In general, a comparatively higher plant population is desirable for determinate varieties. Use of quality seed and good seedbed condition are pre- requisite to maintain the desired field emergence.

3.7 Planting geometry

The ideal planting geometry with row spacing of 45 and 30 cm is recommended for northern, central and southern zones respectively while plant to plant spacing is at 4–5 cm and 7.5–10 cm respectively. For delayed sowing due to late-onset of monsoon, to tcompensate yield reductions owing to reduced vegetative growth along with early flowering can be achieved to some extent by reducing the row to row spacing (30 cm) and increasing the seed rate by 25%. To ensure good germination and subsequent plant stand the seed should be placed at the depth of 3–5 cm.

3.8 Seed rate

Seed rate is dependent on seed index and germination ability, and percentage.

1. Small seeded variety—60–65 kg/ha

2. Medium seeded variety—65–70 kg/ha

3. Bold seeded variety—70–75 kg/ha

The required seed rate is generally 65 kg/ha.

3.9 Seed treatment, seed inoculation

Seed treatment before sowing achieves the objectives of good seed germination and uniform plant stand, reduction in seed born inoculum, protection of seed and seedling from soil born pathogenic infestations. More than 20 species of fungi are known to affect soybean plant as seed-borne. Therefore, seed treatment becomes most important preventive measure which include

1. Fungicidal seed treatment of Thiram + Carbendazim (2:1) to the seeds at the rate of 3 g/kg seed of soybean.

   OR

   Treating soybean seed with microbial inoculum of Trichoderma Viridi at the rate 5 g/kg seed will effectively prevent collar rot disease and assure good plant establishment.

2. For control of yellow mosaic virus (YMV) infestation to soybean, recommended fungicides are used for seed treatment. Then immediately after the treatment with insecticides like Thiamethoxam 30 FS (flowable concentrates for seed treatment) at the rate of 10 ml/kg seed or Imidacloprid 48 FS (flowable concentrates for seed treatment) at the rate of 1.25 ml/kg seed is recommended.

3. Seed must be treated with Bradyrhizobium japonicum culture at the rate 500 g/65 kg seed, for increasing the number of effective nodules and fixation of atmospheric nitrogen in root nodules of soybean plants.

4. For increasing the solubility of the unavailable phosphorous in soil, it is recommended to treat the seed with phosphorous solubilizing bacteria (PSB) at the rate 500 g/65 kg seed.

3.10 Nutrient management

Soybean is considered to be a moderately exhaustive crop. Application of balanced fertilizer dose ensures better performance of soybean in terms of yield. The integration of organic manures like 5–10-ton farm yard manure (FYM) or 2.5-ton poultry manure/ha before last harrowing with inorganic fertilizers as the basal dose of 25:60–80:40–50:20 N: P2O5:K2O:S kg/ha (at the time of sowing) generally provides nutrition in balanced which will help in harnessing the yield potential of soybean.

As per the soil test report, the recommended micronutrients should be applied by soil or foliar method of application

3.11 Weed management and intercultural operations

Weeds poses major threat to soybean production by the way of yield losses to the extent of 30.5–53%. The critical crop weed coemption period for soybean crop is 20–45 days after sowing (DAS) In general, the mechanical weed control measures in soybean are hand weddings twice, at 20 and 40 DAS are recommended. In kharif season during incessant rains or in case of labor unavailability, chemical weed control promises effective weed control. Application of pre-plant incorporation (PPI) or pre-emergence (PE) or post-emergence (PoE) herbicides and two hands weeding were found equally effective to reduce the weed load in soybean.

1. PE application of Alachlor at the rate 2 kg/ha or Pendimethalin 30% EC at the rate 0.50–0.75 kg ha or Butachlor 50% EC at the rate 1 kg/ha dissolved in 500 l of water is sprayed after sowing but before emergence of soybean, i.e., in 2–3 DAS results in better weed suppression.

2. PoE application of Imazethapyr 10% SL at the rate of 0.25 kg ha dissolved in 500 l of water can sprayed within 7–21 days after emergence of soybean will effective for good weed control.

3.12 Water management

Proper water management at critical growth stages is essential to optimize yield. Stress on account of surplus or shortage soil moisture would be unfavorable growth and yield of soybean. Water requirement of soybean for planting and germination is approximately 100 mm, the total water requirement of soybean is around 500 mm.

Generally, soybean is cultivated as completely rainfed in dryland areas receiving rainfall 600–900 mm or as irrigated in rainfed areas rainfall more than 900–1500 mm. From the rainfall analysis it is concluded that the kharif crops are supposed to undergo the dry spell at least once in its total life cycle. Crop may suffer moisture stress at early season, mid-season or terminal stage due to dry spell. Critical period of soybean for water requirement is planting to emergence, reproductive growth stage, and pod filling stage. Supplemental irrigation should be given from the harvested and stored rainwater whenever there is a dry spell or moisture stress conditions occurs.

In rainfed areas, water stored from runoff during heavy rainfall is collected and stored in storage structures like farm ponds. This harvested and stored water can be utilized during drypell to save crop by giving protective irrigation. For protective irrigations in dryland areas the reuse of harvested rainwater can be efficiently used through micro irrigation system. Adaptation of the micro irrigation systems like sprinkler irrigation system will not only increase the efficiency of water application but will also increase the area under protective irrigation and can rescue more area from moisture stress. The depth of protective irrigation can be 1–2 cm for shallow rooted crops while it can be 3–5 cm for deep rooted crops (Figure 1).

Figure 1.

Sprinkler irrigation system for efficient reuse of harvested rain water.

3.13 Dry spell management

In Indian context dry spells occur in monsoon season invariably. The frequency of the dry spell is increasing in current scenario due to climate change. Moisture stress is a resultant of complex set of several climatic, edaphic, and agronomic factors. It can be characterized by major three varying parameters, i.e., occurrence timing, its intensity, and duration. Reduction of tissue water content, stomatal conductance, metabolic processes, and growth are subsequent effects of Dry spell induced a restricted water supply. Plants develop various adaptive mechanisms in response to moisture stress. These adaptations are drought tolerance and avoidance strategies to defy moisture stress. Under drought conditions, Plants by maintaining favorable water status may avoid moisture stress. Plant may avoid drought either by reducing water loss from leaves or by increasing the capacity of roots for water uptake.

Mitigation strategies of dry spell in soybean are:

1. Planting of more than three varieties as per maturity group.

2. If the occurrence of drought is experienced more frequently, the short durational varieties should be selected for sowing.

3. Organic mulching by applying crop residue at the rate 5 tons/ha after emergence

4. Anti-transparent suitable for soybean crop are like KNO3 at the rate 1% or Glycerol at the rate 5% or MgCO3 at the rate 5%. These are recommended to spry under early period of dryspell conditions and when rainfall is likely to happen in upcoming few days. Avoid the conditions of crop failure and reduce the harmful effects on yield of soybean.

5. Mulching of removed weeds (in-situ) at 30 DAS other crops is also advised.

3.14 Soybean based cropping/intercropping systems

Areas where mean seasonal rainfall is 600–750 mm and the effective growing duration is 20–30 weeks, in that part intercropping is suggested, while the areas having mean annual rainfall more than 750 mm and duration of effective cropping season length is more than 30 weeks, double cropping of soybean is possible. In Madhya Pradesh and Maharashtra, particularly Marathwada region intercropping system of soybean + pigeon pea (4:2 row ratio) is very profitable and is recommended particularly for rainfed cultivation. Early maturing (short duration) pigeon pea varieties are more suitable for intercropping system. Soybean + sorghum or soybean + cotton intercropping is also recommended and practiced on large area in and around Madhya Pradesh (Tables 2 and 3).

Zone	Cropping system	Intercropping system
Central (Madhya Pradesh, Bundelkhand region of U.P., Rajasthan, Gujarat, Northern and western parts of Maharashtra)	Soybean-wheat or chickpea soybean-wheat-corn fodder, soybean-potato, soybean-garlic/potato-wheat, soybean-rapeseed or mustard, soybean-pigeon pea or safflower or sorghum	Soybean + pigeon pea, soybean + corn, soybean + sorghum, soybean + sugarcane, soybean in mango/guava orchards, soybean in agro-forestry
Southern (Karnataka, Tamil Nadu, Andhra Pradesh, Kerala, Southern parts of Maharashtra)	Wheat-soybean-finger millet-peas, oat-cowpea-barley-soybean, soybean-finger millet-beans, soybean-wheat-groundnut	Soybean + pigeon pea, soybean + finger millet, soybean + sugarcane, soybean + sorghum, soybean + groundnut, soybean in coconut/mango/guava orchard and soybean in agro-forestry
Northern Plain (Punjab, Haryana, Delhi, North-Eastern plains of U.P., Western Bihar)	Soybean-wheat, soybean-potato, soybean-chickpea	Soybean + pigeon pea, soybean + corn, soybean + sorghum, soybean in mango/guava orchards, soybean in agro-forestry
Northern hill (Himachal Pradesh, North Hills of U.P.)	Soybean-wheat, soybean-pea, soybean-lentil, soybean-Toria	Soybean + corn, soybean + pigeon pea
Northeastern (Assam, Meghalaya, West Bengal, Bihar, Orissa)	Soybean-paddy, paddy-soybean	Soybean + finger millet, soybean + paddy, soybean + pigeon pea

Table 2.

Soybean based remunerative cropping/intercropping system for different zones of India.

Source: From [5, 6].

Treatments	Pooled mean
	Soybean yield (kg/ha)	GMR (Rs./ha)	NMR (Rs./ha)	BC ratio	RWUE
Main plots: land configurations: (03)
L1: Flat bed	1148	34782	9263	1.36	2.77
L2: BBF	1460	44191	18587	1.72	3.50
L3: ridges and furrow	1321	39984	14232	1.54	3.16
SE ±	45.46	1145	341.6	—	—
CD at 5%	125.8	3168	976.4	—	—
Fertilizer cum stress management practices: (108)
F1: RDF (30:60:30 NPK kg/ha)	1140	34670	11457	1.48	2.81
F2: RDF + KNO3 @ 1% and 2% (two sprays)	1421	42954	17545	1.68	3.35
F3: RDF + (19:19:) @ 0.5%	1384	41884	16448	1.64	3.31
F4: RDF + MoP @ 1% and 2%	1290	39099	14386	1.57	3.11
F5: RDF + micronutrients mixture @ 0.5%	1440	43329	17624	1.68	3.34
F6: RDF + straw mulch @ 3 tons/ha	1348	40738	13958	1.05	2.98
F7: RDF + Anti-transparent Kaolin @ 7%	1224	37735	9105	1.31	2.98
F8: RDF + water sprays	1211	36797	12570	—	—
SE +	37.75	1298	856.3	—	—
CD at 5%	104.4	3592	2401.6	—	—
Interaction SE+	65.39	2248	1031.5	—	—
CD at 5%	180.9	6223	1698.5	—	—

Table 3.

Soybean seed yield (kg/ha), gross monetary returns (GMR), net monitory returns (NMR), benefit cost (BC) ratio and rain water use efficiency (RWUE) as influenced by different treatments (2014–2016).

The soybean-based cropping systems are not only productive but they have been profitable as good energy-efficient under various agro-climatic conditions. It is also advisable to farmers that continuous growing of soybean on the same piece of land should be avoided. Crop rotation tactics should be followed for sustainable soybean production (Figure 2) [6].

Figure 2.

Soybean + pigeon pea intercropping system in 4:2 row proportion is widely adopted system under rainfed conditions of Marathwada region.

3.15 Conservation agriculture in soybean

Looking at the sustainability of the natural resources, CA is the promising system. CA is a broad term and it encompasses all conserving techniques that conserve resources anyway. It also involves the following technologies:

1. A minimum level of soil inversion (reduced or zero tillage)

2. Sensible and profitable crop rotation (inclusion of legume crops, cover crops)

3. Soil cover (through crop residues retention on the soil surface)

Resource conserving techniques confirm the optimal utilization of resources and improve input use efficiency. These practices include reduced tillage or zero tillage or no tillage, integrated crop management approaches, retaining crop residue and Use of beneficial microorganisms helpful in increasing both the biological fertility of soil and crop production. CA practices decrease resource degradation. Slow breakdown of surface residues which recovers soil organic matter status, soil microbial and biological activity, and diversity. These practices also contributes to the overall enhancement in soil quality. Sustainable improvements in efficient use of water and nutrients by improving nutrient balance and availability, infiltration, and retention by the soil, reducing water loss due to evaporation.

3.16 Minimum/zero tillage

Minimum tillage is aimed at reducing tillage to the minimum necessary. It ensures a good seedbed, rapid seed germination, a satisfactory plant stand, and promising growing conditions. Minimum tillage will benefit in soil setting, improve soil infiltration, reduce soil resistance and soil compaction along with reduction in soil erosion. Although it has some adverse effects like lower seed germination, additional nitrogen requirement, hampers nodulation in some legumes, requires specially designed implements, development of herbicide residue and its pollution, and the perennial weeds become difficult to control.

Zero tillage is an ultimate form of CT in which mechanical soil manipulation is diminished to traffic and sowing only. In India at present area under zero tillage is 2.0 million ha and potential area is 2.0 million ha and 10 million ha. It is very supportive in the area of intensive cultivation where a turnaround period between two crops is very less and which can facilitate timely sowing. Zero tillage offers the benefit of reduced fuel consumption and labor expenses, reduction of total cost of cultivation, timely sowing is possible which offers yield advantage, reduced soil loss and erosion ultimately improvement in soil health.

3.17 Broad-bed and furrow system

BBF method comprised of the formation of broad-beds of 135 cm wide and 20 cm elevated beds and divided by 45 cm wide furrows, which are to a depth of 20 cm and graded across the contour to a 0.5% slope [7]. The main purpose of this system is to provide acceptable drainage during heavy rainfall events and draining excess rain water into grassy waterways or farm ponds. This stored rain water will be used to provide supplemental irrigation to Kharif and Rabi crops during dry spells. It will reduce runoff and soil loss, and for in-situ moisture conserving in the furrows. The movement of rain water in BBF system is in both the directions, i.e., vertically downward in furrows and laterally in micro and macro pores in the raised broad beds which enhances the efficient use of rain water.

National Innovations on Climate Resilient Agriculture Project (NICRA) adopted villages in Southern and Central parts of India, farmers who implemented broad bed furrow (BBF) sowing technique in soybean by BBF planter evaded injury to the crop owing to surplus rainfall during Kharif seasons of 2013, 2019, 2020, 2021 and gained about 40% yield benefit compared to flatbed sowing. BBF method for, soybean, cotton, pigeon pea and maize saved crop damage due to excess soil moisture by aiding quick drainage and avoiding water stagnation.

BBF planter (Figure 3) facilitates the simultaneous preparation of broad beds and furrows (for soil and water conservation, in which furrows acting as safe drainage channels during heavy rainfall events (Figure 4) sowing of the seed with less seed requirement (kg/ha), deep placement of fertilizers below the seed enhancing the fertilizer use efficiency, which reduces the time, labor, energy and cost of cultivation (Figure 5).

Figure 3.

Sowing of soybean with BBF planter.

Figure 4.

Furrows acting as safe drainage channels during heavy rainfall events in soybean sown with BBF method.

Figure 5.

Soybean sown with BBF method.

3.18 Crop residue management

In India about 400 million tons of crop residues are produced annually. A large quantity of crop residues is left in the field when mechanical harvesting is practiced. This crop residue can be recycled which increases the organic carbon content in soil, as well as nutrient supply. About 25% of nitrogen (N) and phosphorus (P), 50% of sulfur (S), and 75% of potassium (K) uptake by cereal crops are retained in crop residues, making them valuable nutrient sources. Mulching with crop residues contributes to the conservation of soil and rainwater (Figure 6).

Figure 6.

Crop residue management for conservation of soil and rain water in Soybean.

This technique reduces evaporative losses of soil moisture, nutrient loss along with runoff. Contrasting removal or burning of crop residue, incorporation of straw builds up soil from cropped fields. Crop residues modify soil biological activity resulting in improved soil fertility and better soil physical conditions.

Application or retention of crop residue at 2–5 tons/ha will conserve the soil moisture will also help in conservation of soil health.

4. Conclusion

It may be concluded that with the use of appropriate improved climate resilient production technology, there is great scope to achieve the targeted average productivity. The adoption of the climate resilient practices like selecting suitable varieties, sowing in proper sowing window, BBF method of sowing, dry spell management practices, intercropping in soybean, resource conservation techniques can mitigate the effects of climate change and enhance the productivity of soybean in sustainable manner.