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Sensor-based decision tools provide a quick assessment of nutritional and physiological health status of crop, thereby enhancing the crop productivity. Therefore, a 2-year field study was undertaken with precision nutrient and irrigation management under system of crop intensification (SCI) to understand the applicability of sensor-based decision tools in improving the physiological performance, water productivity, and seed yield of soybean crop. The experiment consisted of three irrigation regimes [I1: standard flood irrigation at 50% depletion of available soil moisture (DASM) (FI), I2: sprinkler irrigation at 80% ETC (crop evapo-transpiration) (Spr 80% ETC), and I3: sprinkler irrigation at 60% ETC (Spr 60% ETC)] assigned in main plots, with five precision nutrient management (PNM) practices{PNM1-[SCI protocol], PNM2-[RDF, recommended dose of fertilizer: basal dose incorporated (50% N, full dose of P and K)], PNM3- [RDF: basal dose point placement (BDP) (50% N, full dose of P and K)], PNM4-[75% RDF: BDP (50% N, full dose of P and K)] and PNM5-[50% RDF: BDP (50% N, full P and K)]} assigned in sub-plots using a split-plot design with three replications. The remaining 50% N was top-dressed through SPAD assistance for all the PNM practices. Results showed that the adoption of Spr 80% ETC resulted in an increment of 25.6%, 17.6%, 35.4%, and 17.5% in net-photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and intercellular CO2 concentration (Ci), respectively, over FI. Among PNM plots, adoption of PNM3 resulted in a significant (p=0.05) improvement in photosynthetic characters like Pn (15.69 µ mol CO2 m-2 s-1), Tr (7.03 m mol H2Om-2 s-1), Gs (0.175 µmol CO2 mol-1 year-1), and Ci (271.7 mol H2O m2 s-1). Enhancement in SPAD (27% and 30%) and normalized difference vegetation index (NDVI) (42% and 52%) values were observed with nitrogen (N) top dressing through SPAD-guided nutrient management, helped enhance crop growth indices, coupled with better dry matter partitioning and interception of sunlight. Canopy temperature depression (CTD) in soybean reduced by 3.09-4.66°C due to adoption of sprinkler irrigation. Likewise, Spr 60% ETc recorded highest irrigation water productivity (1.08 kg ha-1 m-3). However, economic water productivity (27.5 INR ha-1 m-3) and water-use efficiency (7.6 kg ha-1 mm-1 day-1) of soybean got enhanced under Spr 80% ETc over conventional cultivation. Multiple correlation and PCA showed a positive correlation between physiological, growth, and yield parameters of soybean. Concurrently, the adoption of Spr 80% ETC with PNM3 recorded significantly higher grain yield (2.63 t ha-1) and biological yield (8.37 t ha-1) over other combinations. Thus, the performance of SCI protocols under sprinkler irrigation was found to be superior over conventional practices. Hence, integrating SCI with sensor-based precision nutrient and irrigation management could be a viable option for enhancing the crop productivity and enhance the resource-use efficiency in soybean under similar agroecological regions. [ABSTRACT FROM AUTHOR]

Environmental crises, declining factor productivity, and shrinking natural resource is a threat to global agricultural sustainability. The task is much more daunting in the Indo-Gangetic northern plains of India, where depletion of the underground water table and erratic rains due to the changing climate pose a major challenge to agriculture. To address these challenges a field investigation was carried out during 2016–2018 to test the efficacy of biopolymeric superabsorbent hydrogels namely Pusa Hydrogel (P-hydrogel: a semi-synthetic cellulose derivative-based product) and kaolin derivative of Pusa Hydrogel (K-hydrogel: semi-synthetic cellulose derivative) to assess their effect on crop and water productivity, soil moisture, root dynamics, and economics of soybean (Glycine max L.)–wheat (Triticum aestivum L.) system under three irrigation regimes namely full irrigation, limited irrigation and rainfed. The results revealed that the full irrigation along with P-hydrogel led to enhanced grain yield, biomass yield, and water productivity (WP) of soybean (1.61–10.5%, 2.2–9.5%, and 2.15–21.8%, respectively) and wheat (11.1–18.3%, 12–54% and 11.1–13.1%, respectively) over control plots. Likewise, under water stressed plots of rainfed conditions with P-hydrogel exhibited 52.7 and 20.6% higher system yields (in terms of wheat equivalent yield) over control and other combinations during the respective study years. Whereas the magnitude of increase in system yield under limited irrigation with P-hydrogel was ~ 15.1% and under full irrigation with P-hydrogel was 8.0–19.4%. Plots treated with P-hydrogel retained 3.0–5.0% higher soil moisture compared to no-hydrogel plots, while K-hydrogel treated plots held the lower moisture (4.0–6.0%) than the control. In terms of profitability, full irrigation along with P-hydrogel plots registered 12.97% higher economic returns over control. The results suggested that P-hydrogel (2.5 kg ha−1) reduces runoff water loss in full irrigation applied plots and retained more water, where loss of water is more thus reduces number of irrigations. Hence P-hydrogel with irrigation water is a viable option for sustainable production of soybean-wheat systems in the Indo-Gangetic plains of India and other similar eco-regions of the world. [ABSTRACT FROM AUTHOR]

Inadequate nutrient management is one of the major challenges for sustainable soybean production in semi-arid climatic conditions. Hence, a 3-year (2015–2017) field experiment was conducted to assess the effect of foliar application of macro- and micronutrients on the growth, productivity, and profitability of soybean. Eight foliar nutrient sprays at the pod initiation stage—water spray (WS), 2% urea solution, 2% di-ammonium phosphate solution (DAP2%), 0.5% muriate of potash solution (MOP0.5%), 2% solution of 19:19:19 nitrogen phosphorus and potassium (NPK2%), and a 0.5% solution each of molybdenum (Mo0.5%), boron (B0.5%), chelated-zinc (Zn 0.5%) and no-foliar nutrition (NFN)—were compared with a basal-applied recommended dose of fertilizers (RDF: 30 kg N, 75 kg P, and 40 kg K ha−1) in a randomized block design (RBD), replicated three times. Foliar-applied chelated Zn@0.5% (Zn0.5%) at the pod initiation stage resulted in more pods per plants. In addition to Zn0.5%, urea2%, NPK2%, and B0.5% significantly improved the pods per plant over treatment by no-foliar nutrition (NFN). The RDF-supplied soybean subsequently sprayed with Zn0.5% produced the highest seed yield, which was 18.5–37.8% higher than that of NFN treatment Yield improvement due to the application of B0.5%, DAP2%, and urea2% varied between 19.2–23.7, 16.6–20.4 and 18.6–20%, respectively. Foliar nutrition showed the largest net returns from Zn0.5%. The water-use efficiency (WUE) and production efficiency increased by 18.4–37.6 and 34.9–37.5%, respectively, due to Zn0.5% over the efficiencies from NFN treatment. Monetary efficiency (ME) gains due to Zn0.5% were 24% higher, while ME efficiency gains due to urea2%, NPK2%, and B0.5% varied between 15–16%. Thus, this study suggested that the foliar application of 0.5% Zn and B, urea, NPK fertilizer, and DAP at 2%, along with RDF. is a profitable nutrient management option for quality soybean production in a semiarid region. However, nutrient partitioning, changes in soil chemical and biological indicators, and environmental aspects need critical examination in future studies. [ABSTRACT FROM AUTHOR]

The sustainability of agricultural production systems is significantly threatened due to climate change and land degradation. Agricultural practices like conventional tillage with imbalanced fertilizers, and indiscriminate irrigation have serious environmental implications like higher greenhouse gas (GHG) emissions. Therefore, we assessed the three-year productivity, effectiveness of energy, and carbon (C) footprint of soybean–wheat system under different tillage techniques [zero-till flat beds (ZTFB), conventional till-raised beds (CTRB), and conventional till- flat beds (CTFB)], irrigation regimes [irrigation at 25%, 50%, and 75% depletion of available soil moisture (DASM)] and fertilizer rates [50% and 100% recommended rates of fertilizers (RRF). The study was conducted for three years in a fixed-field plots using split-split plot design with three replications. The results show that conventional till-raised bed (CTRB) recorded higher system crop productivity (9.5–15.2%), energy-efficiency (17.3), C-output (6424), C-efficiency (11.7), C-sustainability index (9.73), net-returns (1035 US$ ha−1) and the least C-footprints (0.19) over conventional till-flat beds (CTFB) and zero till-flat beds (ZTFB). Whereas, residue mulched ZTFB plots exhibited ∼24.2% higher system water productivity and consumed less energy (∼77.0%) over others. Irrigation applied at 25% depletion of available soil moisture (DASM 25%) led to higher system productivity (5.96 Mg ha−1), energy output (232.6 GJ ha−1), energy-efficiency (13.4) and C-output (6657.4 kg CE ha−1) compared to DASM 75% and DASM 50%. Interestingly, C-footprints increased with ZTFB while least C-footprints were found under CTRB and CTFB. Consequently, the adaptation of CTRB with optimal irrigation and fertilizers will be a viable alternative for achieving improved system production, energy efficiency with a lower C-footprint under semi-arid regions. • Assessed soybean-wheat carbon footprint (CFs) for tillage, irrigation and fertilizers. • Raised beds (FIRB) enhanced system productivity, energy-efficiency, and C-index. • CFs are highest in zero-till+residue (ZTFB), while least under raised-beds. • ZTFB resulted in ∼5.6%− 31.1% increase in soybean and wheat yields over control. • Raised-beds+DASM 25% +fertilizer 100% improved energy efficiency, while reducing CFs. [ABSTRACT FROM AUTHOR]

Soybean ( Glycine max L. Merr.) is largely grown in moisture-stressed conditions resulting in low yield. A 3-year field experiment was conducted during rainy seasons of 2012–2014 to determine: (i) the effects of straw mulches and anti-transpirants on soil moisture retention, rainwater-use efficiency (RWUE), photosynthesis, growth, yield, and quality of soybean (cv. PS 1347), and (ii) the influence of climate (year) on responses of soybean to straw-mulch and anti-transpirant application. The treatments included two mulching treatments, no-mulch and wheat residue mulch (at 5 Mg ha −1 ), and the use of anti-transpirants, MgCO 3 (5%), glycerol (5%), Na 2 CO 3 (2%), KNO 3 (1%) and no-anti-transpirant (control) sprayed 15 days after flower initiation. Wheat straw mulching enhanced surface soil (0–30 cm) moisture content by 20% over plots under no-mulch, improved leaf SPAD (soil plant analysis development) values, net-photosynthetic rates and boosted soybean grain yield by ∼16% over no-mulching. Plots with wheat straw mulching also had ∼18, 18 and 17% higher protein yield, oil yield and RWUE compared with no-mulch plots. Spraying MgCO 3 and KNO 3 along with wheat residue mulching (5 Mg ha −1 ) caused significant enhancement in grain-and protein-yield, and RWUE over control. However, Na 2 CO 3 was not a suitable anti-transpirant as it reduced soybean growth, yield and quality. These results suggest that wheat residue mulch and anti-transpirants, MgCO 3 and KNO 3 , can significantly improve the yield and quality of soybean in moisture-stressed rainfed environments. [ABSTRACT FROM AUTHOR]

Due to depleting water supplies and the cultivation of high water-demanding crops like rice, water deficit in crop production has become a major concern, especially in semi-arid regions of South Asia. Soybean has been considered a possible substitution for high-water-demand crops with improved water productivity and nutrient quality. However, due to inefficient and injudicious water and fertilizer management, the overall productivity and profitability of soybean is quite low. Hence, a three-year field investigation was carried out using strip-strip plot design with three replications to study the individual and combined effects of tillage, irrigation, and fertilizer levels on crop yield and quality, soil moisture and soil microbial dynamics. Results revealed that zero tilled-flat beds (ZTFB) and conventional tilled-raised beds (CTRB) reduced the irrigation water requirement by 5.15–5.45 and 3.12–3.49 cm ha−1, respectively, compared to conventional tilled-flat beds (CTFB). Moreover, CTRB enhanced seed yield by 8.1–31.5 %, biomass yield by 6.5–34.1 %, crop water productivity (CWP) by 27.2–30.9 %, and irrigation water productivity (IWP) by 55.2–57.5 % over CTFB. Similarly, in 2016 and 2017, CTRB had higher SPAD-chlorophyll content (34.3 and 33.2 in the top leaves) and normalized difference vegetation index (NDVI) (0.51 and 0.71) values than CTFB and ZTFB. At 0.0–0.30 m soil depth, ZTFB showed the highest soil moisture content of 11.2 % and 22.5 %, respectively, leading to the highest relative water content (RWC) of 76.7–78.7 % in soybean leaves. As a result, ZTFB took 4–8 days longer to mature than CTFB, delaying the sowing of the following wheat crop. During the 2016–2018 growing seasons, irrigation applied at the depletion of available soil moisture (DASM) by 25 % and 100 % rate of recommended fertilizer (RRF) achieved significantly higher crop, biomass yields, protein yield, SPAD, NDVI, and CWP than irrigation at lower levels. Interaction effects revealed that combinations of CTRB and ZTFB + 25 % DASM + 100 % RRF strategies generated significantly (P ≤ 0.05) higher seed yield, biomass yield, and CWP. At the same time, ZTFB had significantly higher alkaline and acid phosphatase activity than CTRB, whereas the latter had significantly higher soil microbial biomass carbon. In comparison to individual use of these crop management methods, the results of this study showed planning soybean either in CTRB or ZTFB, irrigating at 25 % DASM, and fertilizing crops with 100 % RRF could help achieve higher crop and water productivity, thus sustaining soybean production in India and adjoining regions with similar agro-ecology. • Tillage, irrigation and fertilizer rates on soybean growth were studied in three years. • CTRB+DASM 25 % + 100 % fertilizer rate enhanced soybean yield and resource use efficiency. • Due to higher soil moisture content, a soybean grown in ZT-flat beds matures later. [ABSTRACT FROM AUTHOR]