System of wheat intensification (SWI): Effects on lodging resistance, photosynthetic efficiency, soil biomes, and water productivity.

Intense cultivation with narrow row spacing in wheat, a common practice in the Indo-Gangetic plains of South Asia, renders the crop more susceptible to lodging during physiological maturity. This susceptibility, compounded by the use of traditional crop cultivars, has led to a substantial decline in overall crop productivity. In response to these challenges, a two-year field study on the system of wheat intensification (SWI) was conducted. The study involved three different cultivation methods in horizontal plots and four wheat genotypes in vertical plots, organized in a strip plot design. Our results exhibited that adoption of SWI at 20 cm × 20 cm resulted in significantly higher intercellular CO2 concentration (5.9-6.3%), transpiration rate (13.2-15.8%), stomatal conductance (55-59%), net photosynthetic rate (126-160%), and photosynthetically active radiation (PAR) interception (1.6-25.2%) over the existing conventional method (plant geometry 22.5 cm × continuous plant to plant spacing) of wheat cultivation. The lodging resistance capacity of both the lower and upper 3rd nodes was significantly higher in the SWI compared to other cultivation methods. Among different genotypes, HD 2967 demonstrated the highest recorded value for lodging resistance capacity, followed by HD 2851, HD 3086, and HD 2894. In addition, adoption of the SWI at 20 cm × 20 cm enhanced crop grain yield by 36.9-41.6%, and biological yield by 27.5-29.8%. Significantly higher soil dehydrogenase activity (12.06 µg TPF g-1 soil hr-1), arylsulfatase activity (82.8 µg p-nitro phenol g-1 soil hr-1), alkaline phosphatase activity (3.11 n moles ethylene g-1 soil hr-1), total polysaccharides, soil microbial biomass carbon, and soil chlorophyll content were also noted under SWI over conventional method of the production. Further, increased root volumes, surface root density and higher NPK uptake were recorded under SWI at 20×20 cm in comparison to rest of the treatments. Among the tested wheat genotypes, HD-2967 and HD-3086 had demonstrated notable increases in grain and biological yields, as well as improvements in the photosynthetically active radiation (PAR) and chlorophyll content. Therefore, adoption of SWI at 20 cm ×20 cm (square planting) with cultivars HD 2967 might be the best strategy for enhancing crop productivity and resource-use efficiency under the similar wheat growing conditions of India and similar agro-ecotypes of the globe.

Sulfonated nitrogen and added-sulfur sources influence productivity, quality, and nutrient acquisition of soybean-wheat cropping system.

Soybean-wheat is the predominant cropping system covering >2.5 Mha area in India. The lower productivity of soybean-wheat cropping system (SWCS), remains a serious concern primarily due to inadequate nutrient management. Increasing sulfur (S) deficiency is widespread, especially under oilseed-based cropping system. Hence, to standardize the S requirement through customized fertilization, an experiment was conducted in completely randomized block design (RBD) comprised of 12 nutrient sources, replicated thrice. The study aims to evaluate the agronomic performance of sulfonated nitrogen (SN) in comparison to conventional S nutrient sources in SWCS. The maximum soybean productivity was recorded under NPK + S through 40-0-0-13 (SN1), although NPK + 50% S (15 kg/ha) as basal and 50% (15 kg/ha) as top dressing through SN2 10-0-0-75 produced maximum wheat grain yield. When compared with no nitrogen (control), the application of 30 kg S ha-1 to both crops increased the productivity of the soybean-wheat cropping system up to 39%. The maximum system (SWCS) productivity (8.45 tha-1) was obtained with the application of 50% S as basal and 50% as top dressing (SN2-based), remaining N through urea. The highest sustainable yield index of soybean (SYIS), i.e. 0.90 was under SN1+ remaining N through urea and likewise highest sustainable yield index of wheat (SYIW) was under S splitting. The application of SN also improved the nutrient acquisition and grain quality of soybean and wheat with a positive nutrient balance in the soil. The protein content and yield of soybean and wheat grains also improved. The higher gluten content in wheat grain was produced with 60 kg S ha-1 applied. The agronomic efficiency of N and S (AEN and AEs) were highest under SN1 and SN2, respectively (32.8 kg grain/kg N applied; 15 kg grain/kg S applied) in soybean, however in wheat, S splitting and urea application resulted in highest agronomic efficiency (AEN and AES) of N and S (17.1 kg grain/kg N applied; 22.3 kg grain/kg S applied respectively). Hence splitting of S doses of SN along with urea and recommend P, K was found efficient for the soybean-wheat cropping system.

Changes in microbial community structure and yield responses with the use of nano-fertilizers of nitrogen and zinc in wheat-maize system.

The growing popularity of nano-fertilization around the world for enhancing yield and nutrient use efficiency has been realized, however its influence on soil microbial structure is not fully understood. The purpose of carrying out this study was to assess the combined effect of nano and conventional fertilizers on the soil biological indicators and crop yield in a wheat-maize system. The results indicate that the at par grain yield of wheat and maize was obtained with application of 75% of recommended nitrogen (N) with full dose of phosphorus (P) and potassium (K) through conventional fertilizers along with nano-N (nano-urea) or nano-N plus nano-Zn sprays and N100PK i.e. business as usual (recommended dose of fertilizer). Important soil microbial property like microbial biomass carbon was found statistically similar with nano fertilizer-based management (N75PK + nano-N, and N75PK + nano-N + nano-Zn) and conventional management (N100PK), during both wheat and maize seasons. The experimental data indicated that the application of foliar spray of nano-fertilizers along with 75% N as basal is a sustainable nutrient management approach with respect to growth, yield and rhizosphere biological activity. Furthermore, two foliar sprays of nano-N or nano-N + nano-Zn curtailed N requirement by 25%, furthermore enhanced soil microbial diversity and the microbial community structure. The specific microbial groups, including Actinobacteria, Bacteroidia, and Proteobacteria, were present in abundance and were positively correlated with wheat and maize yield and soil microbial biomass carbon. Thus, one of the best nutrient management approaches for sustaining productivity and maintaining sound microbial diversity in wheat-maize rotation is the combined use of nano-fertilizers and conventional fertilizers.

Optimizing polyhalite (POLY-4) use in the maize-wheat system: A comparative case study from upper and Trans Indo-Gangetic plains of India.

Increasing complexity in crop nutrient requirement in intensive crop production systems needs alternate multi-nutrient sources. Polyhalite (POLY-4) which contains 14% K2O along withcalcium (17% CaO), magnesium (6% MgO), and sulfur (19% S) can be a possible recourse in this regard. In maize-wheat systems, it was evaluated for productivity, profitability, nutrient usage, and nutrient use efficiency under Indo-Gangetic plain (IGP) zones for consecutive two years (2018-19 and 2019-20). The results revealed that 150% K through POLY-4 produced the maximum maize grain yield under the Trans Indo-Gangetic plains (TGP). The maize grain yield increased by 20.8% and 26.2% under 100% K (POLY-4) and 150% K (POLY-4) over No-K, respectively. But statistically, 100% K (POLY-4) stands similar with both 150% K (POLY-4) and 150% K through muriate of potash (MOP) and equivalent. The trends were noticed under upper Indo-Gangetic plain zones (UGP) also. Similarly, the maximum wheat grain yield (6.12 and 6.29 t/ha under TGP and UGP, respectively) was obtained under 150% K (POLY-4), and remained statistically at par with 100% K (POLY-4), but significantly higher than 150% K (MOP). Under both agro-ecologies i.e. TGP and UGP, the highest system productivity was obtained with recommended N, P, and 150% K application through POLY-4. The added return over NPK remained highest with 150% K (POLY-4) for both maize and wheat. However, higher partial factor productivity for N and S, agronomic, physiological, and translocation efficiencies were noticed under 150% K (POLY-4), and remained at par with 100% K (POLY-4). Increased system yield, added returns, partial factor productivity, agronomic, physiological, and translocation efficiencies under 100% K through POLY-4 (along with recommended N and P) proved its effectiveness as multi-nutrient source for the maize-wheat system under TGP and UGP.

Conjoint application of nano-urea with conventional fertilizers: An energy efficient and environmentally robust approach for sustainable crop production.

One of the biggest challenges to be addressed in world agriculture is low nitrogen (N) use efficiency (<40%). To address this issue, researchers have repeatedly underlined the need for greater emphasis on the development and promotion of energy efficient, and environmentally sound novel fertilizers, in addition to improved agronomic management to augment nutrient use efficiency for restoring soil fertility and increasing farm profit. Hence, a fixed plot field experiment was conducted to assess the economic and environmental competency of conventional fertilizers with and without nano-urea (novel fertilizer) in two predominant cropping systems viz., maize-wheat and pearl millet-mustard under semi-arid regions of India. Result indicates that the supply of 75% recommended N with conventional fertilizer along with nano-urea spray (N75PK+nano-urea) reduced the energy requirement by ~8-11% and increased energy use efficiency by ~6-9% over 100% nitrogen through prilled urea fertilizer (business as usual). Furthermore, the application of N75PK+ nano-urea exhibited ~14% higher economic yields in all the crops compared with N50PK+ nano-urea. Application of N75PK+nano-urea registered comparable soil N and dehydrogenase activities (35.8 µg TPF g-1 24 hrs-1 across all crops) over the conventional fertilization (N100PK). This indicates that application of foliar spray of nano-urea with 75% N is a soil supportive production approach. More interestingly, two foliar sprays of nano-urea curtailed nitrogen load by 25% without any yield penalty, besides reducing the greenhouse gases (GHG) emission from 164.2 to 416.5 kg CO2-eq ha-1 under different crops. Therefore, the application of nano-urea along with 75% N through prilled urea is an energy efficient, environmentally robust and economically feasible nutrient management approach for sustainable crop production.