Soybean-wheat Cropping System Research Articles

English

The aim of this research work was to prepare rock phosphate enriched compost using low-grade mineral such as rock phosphate (RP) mixed with rice straw and Aspergillus awamori and to study their effect on microbial biomass phosphorus (MBP), phosphatase activity and phosphorus (P) fractions in a wheat-soybean cropping system. The experiment was carried out in a randomized block design with four treatments namely, control, recommended dose of NPK fertilizers (100% RDF), rock phosphate enriched compost (RPEC) at the rate of (5 t ha-1 and 50% RDF + Rock phosphate enriched compost (RPEC) at 5 t ha-1. Application of RPEC at 5 t ha-1 along with 50% recommended dose of chemical fertilizers (RDF) significantly improved microbial biomass P (MBP) (5.62 and 4.28 mg kg-1 soil) and alkaline phosphatase activity (194.0 and 174.0 μg PNP g-1 soil h-1) in surface (0-15 cm) and sub-surface (15-30 cm) soil respectively, than unfertilized control plot after harvest of wheat. The magnitude of changes of P fractions as well as microbial activities was higher in surface soil than sub-surface soil. Data generated from the field study revealed that phosphorus (P) fractions significantly increased due to application of RPEC either alone or in combination of chemical fertilizers over unfertilized control plot. Application of RPEC plus chemical fertilizers significant increased Olsen P compared to unfertilized control plot after harvest of wheat and soybean. Treatment T4 increased by 68.8 and 58.7% higher Olsen-P over control at 0-15 and 15-30 cm soil depth, respectively after wheat harvest. Key words: Microbial biomass P, phosphatase enzyme, phosphorus fractions, Olsen P, rock phosphate, rice straw.

Comparison between fertilizers and untreated sewage effluent as sources for nutrient recovery by wheat (Triticum aestivum)-soybean (Glycine max) cropping system

ABSTRACTRecovery and recycling of plant nutrients from municipal sewage effluent (SE) can reduce consumption of costly chemical fertilizers, besides reducing eutrophication of water bodies. Field experiment was conducted on Vertisol of central India for six years with the objective of quantifying recovery of major plant nutrients by aboveground biomass of wheat-soybean cropping system from untreated SE. Wheat crop was grown with irrigation (groundwater and sewage effluent) and fertilizer treatments; while soybean was grown without any treatments. Recoveries of nitrogen (N), phosphorus P) and potassium (K) by the aboveground biomass were considerably more from SE than from fertilizers and manures. Recovery of nutrients from SE was the highest by wheat grain for N and by soybean straw for P and K. Straw biomass of both the crops recovered about 31% N, 22% P and 69% K from SE, which can be recycled back into agricultural land of groundwater (GW) irrigated as well as rainfed area.

Effects of Tillage, Residue and Fertilizer Nitrogen on Crop Yields, and Soil Physical Properties Under Soybean–Wheat Rotation in Vertisols of Central India

Soybean–wheat cropping system is predominant in vertisols of central India. Long-term field experiment was conducted to assess the effect of four tillage systems [conventional tillage (CT), mouldboard tillage (MB), reduced tillage (RT) and no tillage (NT)] and three rates of fertilizer N (50, 100 and 150 % of recommended fertilizer) on crop yields, root growth, soil organic carbon (SOC) content and physical properties in soybean–wheat cropping system. Productivity of soybean and wheat was similar in different tillage systems. Response of fertilizer N was not influenced by tillage systems, and crop response to fertilizer N was generally observed up to 100 % of the recommended N fertilizer. Root length density of soybean in the top 15 cm depth was higher in NT and RT than in MB and CT. An improvement in selected soil physical properties like soil water storage, bulk density, aggregate stability and saturated hydraulic conductivity (Ks) was recorded in NT and RT than in CT. SOC content at 0–15 cm depth was significantly higher in NT, RT and MB where wheat residues were retained after harvest than that in CT system. The SOC, aggregate stability and Ks were significantly higher in N150 % compared to N50 %. It is concluded that no tillage and reduced tillage systems with residue retention and recommended rate of N would be a suitable practice for sustainable production of soybean–wheat cropping system in vertisols of central India.

Effects of amendments and hydrogel application on water retention, water release pattern, growth and yield performance of soybean-wheat cropping system

In a field experiment, water retention and release pattern of a sandy loam (Typic Haplustept) soil was studied along with growth and yield performance during 2009–10 in soybean-wheat cropping system. Main treatment included three amendment types namely FYM, tank soil applied @ 5 t ha−1 and no amendments and sub-treatments included three rates of super hydrogel i.e. 5, 2.5 and 0 kg ha−1, applied at 5-7cm depth along with seed in rows using a manual seed drill. Soil water content at various suction and soil water content changes during drying cycle after watering were monitored. Results revealed that changes in soil water content per unit change in suction became negligible after 100 kPa, therefore soil water content at 100 kPa suction was labeled as critical soil water content (CSWC). Soil water characteristic showed that at all suctions, water retained in gel treatments was always higher. In soybean, when pan evaporation ranged between 4–7 mm day,−1 CSWC in FYM with gel treated plots reached in 14 days, whereas, in other treatments CSWC arrived early. In wheat, during early growth when pan evaporation ranged between 1–1.8 mm day−1, CSWC arrived in 28 days in FYM with gel @ 5 kg ha−1 treatment. Application of hydrogel @ 2.5 kg ha−1 significantly increased the dry biomass, root growth, grain yield and water use efficiency over no hydrogel, while further increased in hydrogel application @ 5 kg ha−1 growth parameters and water use efficiency increased marginally. Results further indicated that a mixture of both FYM and hydrogel was more efficient for improving hydraulic properties of the soil and crop growth parameters than applying each of them alone.

Efficient Nitrogen and Water Management for the Soybean–Wheat System of Madhya Pradesh, Central India, Assessed Using APSIM Model

A series of long-term simulations were carried out to investigate alternative management practices to increase grain yields of soybean and wheat by optimizing sowing dates, nitrogen (N) and water requirements, along with complimenting farmyard manure (FYM) as a N source in the soybean–wheat cropping system of Madhya Pradesh. The APSIM simulation study showed that the mean soybean yield ranged from 1.0 to 1.6 t ha−1 for the different dates of sowing. The average wheat grain yield was 3.2–3.9 t ha−1, whereas, the crop sown on 15 November gave the highest yield. In this region, there is a potential to increase soybean and wheat yields by 0.6 and 2.2 t ha−1, respectively. Among the various irrigation practices simulated, five irrigations of 60 mm at 20 days interval was the best option for wheat. Application of 16 t FYM ha−1 to soybean produced 50 % higher wheat yield than the same amount of FYM applied to wheat. The wheat yield obtained from inorganic application of N was at par with that obtained from the application of integrated and organic sources. However, the amount of N loss from the integrated use of fertilizer N was lower than that from the current recommended practice for the region. Application of FYM alone or in combination with inorganic fertilizer maintained higher soil organic carbon concentration as compared to the application of inorganic fertilizer alone. Thus, the model provided a mean of evaluating alternative crop N and water management options for effectively managing the soybean–wheat cropping system.

Influence of phosphorus and biofertilizers on soybean and wheat root growth and properties

Alteration of crop root morphology is a new innovative approach to provide food security. Phosphorus is the most important nutrient to influence root properties. Efficient use of P fertilizers has become an important issue of agriculture all over the world due to limited availability of rock phosphate and its non-renewable nature. Hence, root properties and grain yield of soybean–wheat cropping system were evaluated by inoculation of phosphate solubilizing bacteria (PSB) and vesicular arbuscular microorganism (VAM) with 50% recommended P (0.5 P+PSB+VAM) against 100% P (1.0 P), 50% P and control in a Typic Ustochrepts of the Indo-Gangetic plains. The root cation exchange capacity (CEC) of soybean and wheat treated with 0.5 P+PSB+VAM were 3.6 and 4.6% higher than 1.0 P, respectively. The same treatment produced 2.3 and 2.6% higher root length density (RLD) in soybean and wheat, respectively in comparison to 1.0 P. The P inflow rate under 0.5 P+PSB+VAM was 9.2 and 4.6% higher than 1.0 P in soybean and wheat, respectively indicating higher acquisition of P through VAM, although higher rhizospheric P availability was recorded in 1.0 P. The root CEC, RLD and P inflow rate were closely related to P concentration and content in root, shoot and nodule, specific root length, root diameter and internal P requirement. The better root property observed in 0.5 P+PSB+VAM enhanced 4.1 and 4.9% grain yield of soybean and wheat, respectively as compared to 1.0 P. Inoculation of PSB and VAM could substitute 50% P of soybean–wheat cropping system with better root property and higher grain yield in semi-arid sub tropics of the Indo-Gangetic plains.

EFFECT OF TILLAGE AND RESIDUE MANAGEMENT ON PRODUCTIVITY OF SOYBEAN AND PHYSICO-CHEMICAL PROPERTIES OF SOIL IN SOYBEAN-WHEAT CROPPING SYSTEM

A microplot experiment was conducted in soybean–wheat cropping system at New Delhi during 2010-11 and 2011-12 to study the effect of continuous or cyclic tillage, viz., conventional tillage (CT) and zero-tillage (ZT) and residue management of either soybean (SR) and/or wheat (WR) on yield performance and soil physico-chemical properties. The experiment was laid out in randomized block design with two replications in microplots of size 4×1.4 m. Plant height of soybean was influenced due to tillage and residue management at different growth stages. All yield attributes of soybean were showed variation due to treatments. The harmful effects of ZT on yield attributes could be overcome with residue application on soil surface. The results indicated that tillage and residue management to the immediate crop of soybean was more important for increasing grain yield (26%) and stover production (32%) of soybean and the residual effect of residue to previous soybean was relatively small. The change in organic C was relatively small even with regular addition of crop residues. There was no change in available nutrients (N, P and K) due to tillage and residue management treatments. The variation in soil physical properties was also small and a significant improvement may be expected over several years of continuous application of crop residue and ZT.

Evaluation of Soil Physical Quality under Amendments and Hydrogel Applications in a Soybean–Wheat Cropping System

A field study was conducted in alluvial sandy loam soil to assess the impact of amendments and hydrogel application on soil hydrophysical properties. Soil physical environment was characterized and quantified using soil physical quality index (S). The main treatments include farmyard manure (FYM) and tank soil applied at 5 t ha−1 and no amendment, and subtreatments included three rates of hydrogel: 5, 2.5, and 0 kg ha−1. Hydrogel was applied at 5–7 cm deep just below the seed in rows. Results revealed that FYM along with gel application at 5 kg ha−1 significantly increased mean weight diameter, field capacity moisture content, plant-available water content and relative field capacity, retention pores (Ret P), water-stable structural units, and structural coefficient and reduced transmission pores (TP), penetration resistance, and saturated hydraulic conductivity (Ks). Significantly greater values of S in hydrogel-treated plots and close associations of S with other soil physical parameters were obtained.

Phosphorus and Potassium Transformations in Soil Amended with Enriched Compost and Chemical Fertilizers in a Wheat–Soybean Cropping System

India imports large amounts of rock phosphate (RP) and potassium (K) fertilizers from other countries; hence, research priorities have been directed toward finding alternative sources of phosphorus (P) and K fertilizers. This study focuses on the transformations of P and K in soil amended with RP and waste mica–enriched compost. The enriched compost had greater total P, K, calcium (Ca), magnesium (Mg), micronutrients, and biological properties than ordinary compost. In a wheat–soybean rotation, application of 5 t ha−1 enriched compost along with 50% of the recommended rate of inorganic fertilizer resulted in increased concentrations of saloid P, iron (Fe) P, aluminum (Al) P, Ca-P, occluded P, water-soluble K, exchangeable K, and nonexchangeable K over unfertilized plots. In addition, plots that received enriched compost had greater microbial biomass and phosphatase activities than unfertilized plots. Thus, enriched compost could be an alternative source of water-soluble P and K fertilizers for crop production.

Low carbon technologies for different cropping systems-A review

Global warming is the rise in the mean temperature of Earth's atmosphere. It is primarily caused by increasing concentration of green house gasses (GHGs) in the atmosphere. This phenomenon widely called as ‘greenhouse effect’. However, agriculture is the major contributor primarily through the emission of methane and nitrous oxide. It was reported in 2007 that the net emission of GHGs from India was 1727.7 MT of CO2 equivalent. It has been shown that Punjab, Haryana, Uttar Pradesh and Andhra Pradesh emit higher amount of NO2-N because of higher nitrogen fertilizer use. But West Bengal, Andhra Pradesh, Orissa, Bihar, Jharkhand and North-eastern States emit more amount of methane due to higher rice cultivation. Conservation agriculture holds key in reducing the emission due to minimum soil disturbance and 30% area covered with crop residue. In this article, the different mitigation strategies in rice-wheat, maize-wheat and soybean-wheat cropping system have been discussed.

Carbon Addition and Storage Under Integrated Nutrient Management in Soybean–Wheat Cropping Sequence in a Vertisol of Central India

Sustenance of soil organic carbon (SOC) in soil is of utmost importance for soil health and sustainable agriculture. Soil carbon storage with turnover rates of biomass under different IPNS modules in a vertisol under the predominant soybean–wheat cropping system of central India revealed improvements in carbon sequestration through balanced and integrated nutrient management. The highest C addition and storage was recorded under 16 and 8 t ha−1 FYM addition to soybean and wheat, respectively. C addition and storage relationship revealed that to maintain the initial SOC 554 kg C ha−1 is required. The vertisol of central India have high C storage potential and the soybean–wheat cropping sequence hold promise to maintain its SOC even in the event of no fertilizer and no manure addition. The decay rate constant of native soil carbon was 0.0061 year−1.

Simulating soybean–wheat cropping system: APSIM model parameterization and validation

In recent years, nutrient management of soybean–wheat systems in central India has become a cause for concern because of stagnation of grain yields of soybean and wheat. The reduction in grain yield was mainly attributed to a suboptimal supply of nutrients to both the crops, use of poor quality farmyard manures and erratic distribution of rainfall during soybean's growing season and unavailability of irrigation water during wheat season. In this connection, the crop growth simulation models are handy in identifying the constraints to yield and recommending appropriate management practices to optimize the productivity of soybean–wheat system. To achieve this, the APSIM model was parameterized and validated for soybean and wheat crop of subtropical central India.Independent data set was used to parameterize soybean cultivar (JS 335) and wheat cultivar (Sujata) to be used for APSIM simulation. Genetic coefficient generated from this study was used for subsequent model validation. The data on water use, N uptake, grain yield and soil organic C from an ongoing long-term experiment was used for validation purpose. Three nutrient treatments, viz., control (no nutrient), inorganic (recommended rate) and FYM (8tha−1 to soybean and 16tha−1 to wheat) were used to validate the APSIM model. For organic treatments, we simulated N management using the FYM as the source of plant available N under field condition. The model was parameterized by specifying the N mineralized from the manure in the laboratory incubation. The model predicted successfully grain yield and N uptake under FYM treatments in soybean and wheat. For other treatments, model prediction was satisfactory in most of the cases in simulating water and organic carbon, grain yield and N uptake by both the crops. The discrepancy observed between the observed and predicted yield in the control under soybean was due to the P limiting condition of the treatment rather than the model. The predicted variability of crop yield was also due to the variation of weather during soybean growing season and amount of irrigation and N used during wheat growing season. Therefore, this APSIM simulation study can satisfactorily be used to make appropriate management decisions to provide farmers and others with alternative options for nutrient management for soybean–wheat cropping systems.

An integrated approach for management of Cyperus rotundus (purple nutsedge) in soybean–wheat cropping system

Cyperus rotundus L. can inflict high yield losses in soybean. There is lack of selective herbicides worldwide as well as integrated approaches for controlling C. rotundus in soybean. This study was undertaken to develop an integrated strategy for its management in a soybean–wheat cropping system. Soil solarization followed by ( fb) glyphosate application at 1.0 kg a.i./ha during the summer fallow resulted in significant reduction in C. rotundus density and dry weight, resulting in higher soybean and wheat yields, system productivity and gross returns in the subsequent rainy seasons, but slightly lower net returns when cowpea was planted in the summer season. Imazethapyr applied at 0.075 kg a.i./ha 20 days after sowing of soybean resulted in comparable system productivity with, but higher net returns than that of hand-weeding twice. However, solarization fb the applications of glyphosate 1.0 kg a.i./ha during summer and imazethapyr 0.075 kg a.i./ha during the rainy-season in soybean will give better C. rotundus control and higher soybean–wheat system productivity compared to other combinations of summer and rainy-season treatments.

Selection of Plant Growth-Promoting Pseudomonas spp. That Enhanced Productivity of Soybean-Wheat Cropping System in Central India

The aim of this investigation was to select effective Pseudomonas sp. strains that can enhance the productivity of soybean-wheat cropping systems in Vertisols of Central India. Out of 13 strains of Pseudomonas species tested in vitro, only five strains displayed plant growth-promoting (PGP) properties. All the strains significantly increased soil enzyme activities, except acid phosphatase, total system productivity, and nutrient uptake in field evaluation; soil nutrient status was not significantly influenced. Available data indicated that six strains were better than the others. Principal component analysis (PCA) coupled cluster analysis of yield and nutrient data separated these strains into five distinct clusters with only two effective strains, GRP3 and HHRE81 in cluster IV. In spite of single cluster formation by strains GRP3 and HHRE81, they were diverse owing to greater intracluster distance (4.42) between each other. These results suggest that the GRP3 and HHRE81 strains may be used to increase the productivity efficiency of soybean-wheat cropping systems in Vertisols of Central India. Moreover, the PCA coupled cluster analysis tool may help in the selection of other such strains.

Biomass production and carbon stocks in poplar-crop intercropping systems: a case study in northwestern Jiangsu, China

The importance of agroforestry systems in CO2 mitigation has become recognized worldwide in recent years. However, little is known about carbon (C) sequestered in poplar intercropping systems. The main objective of this study is to compare the effects of three poplar intercropping designs (configuration A: 250 trees ha−1; configuration B: 167 trees ha−1 and configuration C: 94 trees ha−1) and two intercropping systems (wheat–corn cropping system and wheat–soybean cropping system) on biomass production and C stocks in poplar intercropping systems. The experiment was conducted at Suqian Ecological Demonstration Garden of fast-growing poplar plantations in northwestern Jiangsu. A significant difference in C concentration was observed among the poplar biomass components investigated (P ≤ 0.05), with the highest value in stemwood and the lowest in fine roots, ranging from 459.9 to 526.7 g kg−1. There was also a significant difference in C concentration among the different crop components (P ≤ 0.05), and the highest concentration was observed in the corn ear. Over the 5-year period, the total poplar biomass increased with increasing tree density, ranging from 8.77 to 15.12 t ha−1, while annual biomass production among the crops ranged from 4.69 to 16.58 t ha−1 in the three configurations. Overall, total C stock in the poplar intercropping system was affected by configurations and cropping systems, and configuration A obtained the largest total C stock, reaching 16.7 t C ha−1 for the wheat–soybean cropping system and 18.9 t C ha−1 for the wheat–corn cropping system. Results from this case study suggest that configuration A was a relative optimum poplar intercropping system both for economic benefits and for C sequestration.

Organic manuring for soil biological health and productivity of a wheat - soybean cropping system in the Vertisols of central India

Soybean (Glycine max (L.) Merr.)–wheat (Triticum aestivum L.) is the dominant cropping system in the Vertisols of central India due to congenial climate, development of agro-industries, and export opportunities. Both are high-value crops, and raising them using organics may further improve produce quality and help in sustaining long-term productivity of the system. Information is lacking on how to sustain the system with the sole use of organics or biofertilisers in Vertisols. A long-term study was made during 1995–2002 at Indore, India, to evaluate the effectiveness of 3 organic manures [farmyard manure (FYM), poultry manure (PM) and vermicompost (VC) at varying rates] and biofertilisers (Azotobacter + phosphate solubilising bacteria) on productivity, grain quality, soil fertility, and profitability of a wheat–soybean cropping system. Grain yield of wheat was significantly increased with PM at 2.5–10 t/ha or FYM at 10–20 t/ha compared with the control. However, the highest productivity was obtained with PM at 10 t/ha, which even performed better than NPK, indicating that NPK fertilisers alone did not provide adequate and balanced nutrition for potential yield of the crop. Quality parameters of durum wheat, viz. protein content, hectolitre weight and sedimentation value, increased, while yellow berry content decreased significantly with PM at 2.5–10.0 t/ha compared with the control. Soybean yields were significantly influenced by the residual effect of organic manuring treatment applied to wheat. The treatment receiving PM at 10 t/ha produced the highest grain yield of wheat. However, this treatment could not produce a similar response in soybean yield due to production of excessive vegetative growth, adversely affecting grain yield. Superiority of PM over FYM, vermicompost and biofertilisers was evident in the overall profitability of the system. Various soil fertility parameters including chemical and biological properties showed conspicuous improvement over the initial status under the FYM and PM treatments. Microbial biomass C and activities of phosphatase and dehydrogenase were increased significantly with applications of manures. Sustainability yield index was maximum under PM at 5–10 t/ha, followed by NPK. Results suggested that application of PM at 5–10 t/ha to wheat was essential for improving productivity, grain quality, profitability, soil health, and sustainability of a wheat–soybean system.

Sustaining productivity of wheat–soybean cropping system through integrated nutrient management practices on the Vertisols of central India

Wheat–soybean is one of the most dominant cropping systems on the Vertisols of central India. Cultivation of durum wheat in winter season (November to April) has a considerable potential due to congenial climate, while soybean in rainy season (June to October) has witnessed a phenomenal growth in the last two decades in the region. Beside including a legume (soybean) in sequence with a cereal crop (wheat), combined use of available organic sources along with chemical fertilizers may prove beneficial for long-term productivity and sustainability of the system. A long-term experiment was conducted during 1995–2000 on the fine-textured Vertisols at Indore, India to study the effect of combined use of farmyard manure (FYM), poultry manure, vermicompost and biofertilizers (Azotobacter + phosphate solubilizing bacteria) with 0.5 and 1.0 NPK (120 kg N + 26.2 kg P + 33.3 kg K ha−1) on wheat, and residual effect on following soybean. Grain yield of aestivum wheat in the initial 2 years and durum wheat in the later 3 years was significantly increased with 0.5 NPK + poultry manure at 2.5 t ha−1 or FYM at 10 t ha−1 compared with 0.5 NPK alone, and was on par with 1.0 NPK. However, the highest productivity was obtained when these organic sources were applied along with 1.0 NPK. Quality parameters of durum wheat viz protein content, hectolitre weight and sedimentation value showed improvement, and yellow berry content was significantly lower with combined use of NPK + organic sources compared with NPK alone and control. Soybean did not show much response to residual effect of nutrient management treatments applied to wheat. Wheat gave higher profit than soybean, particularly in the later years due to lower grain yields and market price of soybean. However, the superiority of FYM as well as poultry manure along with 1.0 NPK was evident on the overall profitability of the system. Various soil fertility parameters including chemical and biological properties showed conspicuous improvement over the initial status under the treatments of FYM and poultry manure. Sustainability yield index was maximum under 1.0 NPK, followed by 1.0 NPK + poultry manure or FYM. It was concluded that application of available organic sources, particularly FYM and poultry manure along with full recommended dose of NPK fertilizers to wheat was essential for improving productivity, grain quality, profitability, soil health and sustainability of wheat–soybean system.

Potassium balance as influenced by farmyard manure application under continuous soybean–wheat cropping system in a Typic Haplaquept

The effect of 30 years of continuous cropping, fertilization and manuring on the potassium (K) balances, the soil K pools and the non-exchangeable K release in a Typic Haplaquept soil from Almora, India under a rainfed soybean–wheat cropping system were investigated. The apparent K balance was measured as the difference between the total K added and that removed by the crops. The results showed that the total removal of K by the crops exceeded the amount of total K applied to the soil in all the treatments showing a net negative K balance. This ranged from 3.7 in the plots under NK to 81.7 kg ha − 1 year − 1 in the N + FYM treated plots. Continuous annual application of recommended doses of NPK + 10 t FYM (NPK + FYM) to soybean resulted in an accumulation (+ 56 kg K ha − 1 ) of exchangeable K (1 N NH 4OAc extractable K) in the 0–45 cm soil depth over the study period, despite the highest average annual uptake of K by the system (150.8 kg ha − 1 year −1). However, there was a net depletion of exchangeable K (− 80 kg K ha − 1 ) in that soil depth under the NPK treated plots. The results also revealed that the content of non-exchangeable K decreased substantially from 3482 kg ha − 1 to 2677 and 2896 kg ha − 1 in the 0–45 cm soil layer after 30 years of cropping in the plots under NPK + FYM and NPK treatments, respectively. There was a significant decline in total soil K with the removal of non-exchangeable soil K in the surface (0–15 cm) soil layer ( R 2 = 0.526, P < 0.001, n = 36). Thus, long-term application of non-revised recommended fertilizer rates may threaten sustainability of the rainfed continuous soybean–wheat system.

Irrigation and Nutrient Effects on Growth and Water–Yield Relationship of Wheat (Triticum aestivum L.) in Central India

AbstractIncreasing production of wheat from a limited water supply can result from efficient irrigation and nutrient management. A 3‐year field experiment was conducted at the Indian Institute of Soil Science, Bhopal, to study the growth, yield, seasonal evapotranspiration (ET) and water use efficiency (WUE), and the water–yield relationship of wheat in a soybean–wheat cropping system on vertisols. Three levels of irrigation, viz. I0, no post‐sowing irrigation; I1, two irrigations [crown root initiation (CRI) and flowering stage]; and I2, three irrigations (CRI, maximum tillering and flowering stage) and three nutrient management treatments, viz. F0, control (without fertilizer/manure); F1, 100 % NPK (100–21.5–24.9 kg ha−1); and F2, 100 % NPK + farmyard manure (FYM‐10 t ha−1) were tested in a split‐plot design with three replication. It has been established (through anova) that the year effect was rather negligible and the interaction effects of irrigation and nutrient management on the growth parameters, ET, yield components, yield and WUE were significant. Plant height, progressive leaf area index, dry matter accumulation and crop growth rate were higher in I2F2, and I2F1 and I1F2 were statistically at par. The seasonal ET increased significantly with the increase in water supply in every nutrient treatment and it was highest in I2F2 and lowest in I0F0. The highest grain yield was obtained in I2F2; and a similar yield was recorded in I3F1 and I2F2. This shows a strong interaction effect between irrigation and nutrients. Yield components, viz. number of ears m−2, number of grains ear−1 and 1000‐grain weight were significant. The higher number of ears m−2 containing greater number of grains with relatively heavier weights appeared to have contributed to the higher yield in I1F2, I2F1 and I2F2. The highest WUE obtained in I0F2 did not correspond to the highest yield and maximum ET, but a WUE of 10.43 kg ha−1 mm−1 in the I2F2 combination corresponded with the highest yield and the seasonal ET requirement was 391.8, which was 137 % greater than the water use at maximum WUE. The ET–grain yield relationship was linear, with a lowest regression slope (i.e. marginal WUE) and elasticity of water production (Ewp) in F0 and a considerably higher slope and Ewp in F1 and F2. As the Ewp is positive and close to one in 100 % NPK treatment, the scope of improving WUE and yield with only inorganic fertilizer is very little, and relatively greater scope exists in the integrated management of organic manure and inorganic fertilizer. The results suggest that integrated nutrient management (100 % NPK + FYM) in conjunction with three irrigations maximized yield of wheat with concomitant improvement in ET and WUE under limited water availability.

Cropping Systems of Central India: An Energy and Economic Analysis

ABSTRACT The study attempts to analyze the energy input-output relationship and economic returns of the cropping systems in central India. The data collected from farmers through multistage random sampling techniques, were subjected to descriptive analysis of simple proportions and percentages. Findings reveal that total energy involved in soybean-wheat system (19817 MJ ha−1; renewable 5507 MJ ha−1 and non-renewable 14310 MJ ha−1) is much greater than soybean-chickpea (11239 MJ ha−1; renewable 4883 MJ ha−1 and non-renewable 6356 MJ ha−1), pigeonpea monocropping (2329 MJ ha−1; renewable 714 MJ ha−1 and non-renewable 1616 MJ ha−1), fallow-wheat (13716 MJ ha−1; renewable 2810 MJ ha−1 and non-renewable 10906 MJ ha−1) and fallow-chickpea (4445 MJ ha−1; renewable 2526 MJ ha−1 and non-renewable 1919 MJ ha−1). The percentage of non-renewable energy is higher than renewable energy inputs. Soybean-wheat (70%) and fallow-wheat (78%) systems resorted to more use of non-renewable energy than renewable energy. In soybean-chickpea system share of non-renewable energy is 52%. The energy outputs follow the order: soybean-wheat (70495 MJ ha−1) > fallow-wheat (52084 MJ ha−1) > soybean-chickpea (44485 MJ ha−1) > pigeonpea monocropping (20427 MJ ha−1) > fallow-chickpea (20357 MJ ha−1); energy efficiency is the highest in pigeonpea mono-cropping (8.76); for other systems it ranged from 3.67 in soybean-wheat to 4.63 in fallow-chickpea system. The net energy of the systems is 50678 MJ ha−1 in soybean-wheat, 38368 MJ ha−1 in fallow-wheat, 33246 MJ ha−1 in soybean-chickpea, 18098 MJ ha−1 in pigeonpea monocropping and 15912 MJ ha−1 in fallow-chickpea. Though the soybean-wheat system results in highest net energy, its energy productivity (0.269 kg MJ−1) is the lowest and that of fallow-wheat system is 0.288 kg MJ−1. It is comparatively higher for other systems, viz., soybean-chickpea (0.307 kg MJ−1), pigeonpea monocropping (0.643 kg MJ−1) and fallow-chickpea (0.342 kg MJ−1). Further, energy intensity is 3.84 MJ kg−1 and 0.887 MJ Rs.−1 in physical and economic terms, respectively, in the soybean-wheat system, and are greater than other systems, viz., soybean-chickpea (3.43 MJ kg−1 and 0.577 MJ Rs.−1), pigeonpea monocropping (1.55 MJ kg−1 and 0.243 MJ Rs.−1), fallow-wheat (3.59 MJ kg−1 and 1.408 MJ Rs.−1) and fallow-chickpea (2.96 MJ kg−1 and 0.569 MJ Rs.−1). But the soybean-wheat cropping system has been found more remunerative in terms of benefit-cost ratio (1.27) owing to its ability to generate the highest return per rupee investment than soybean-chickpea (1.23) and pigeonpea monocropping (1.23). The fallow-based systems are having comparatively better benefit/cost ratio. The investment requirement and also net return is highest for soybean-wheat system, thus is preferred by the large farmers. Farmers are forced to use soybean-chickpea crop rotation whenever there is lack of adequate rainfall during rainy season and irrigation facilities in succeeding winter season. Thus, fallow-chickpea rotation is suitable for extremely poor farmers with no irrigation facilities.