Vinod Kumar Singh

Pearl millet ( Pennisetum glaucum L.) is an important cereal crop in rainfed regions owing to its inherent drought tolerance. However, drought stress adversely affects crop growth, physiological processes and yield. A pot experiment was conducted during the post-monsoon season at ICAR–Central Research Institute for Dryland Agriculture (ICAR-CRIDA), Hyderabad to evaluate the effects of different nano-nutrient foliar sprays on pearl millet under deficit moisture stress. Foliar application of nano-nutrients during and after stress alleviation at the vegetative and flowering stages improved crop growth and yield attributes. Compared with the control, yield losses were limited to 9% and 13% following application of SWAS @ 0.5% after alleviation of vegetative-stage stress and to 13% following application of NDAPAS @ 0.2% after alleviation of flowering-stage stress. At the vegetative stage, foliar application of SWAS at 0.5% resulted in the highest relative water content (RLWC, 93.2%), soil moisture (19.3%), membrane stability index (MSI, 93.2%) and nitrate reductase (NR) activity (2962.2 µg g⁻ ¹ FW) while maintaining lower levels of proline (32.0 µg g⁻ ¹ FW), malondialdehyde (MDA, 15.7 µg g⁻ ¹ FW), free amino acids (FAA, 21.2 µg g⁻ ¹ FW) and total soluble sugars (TSS, 1.8 µg g⁻ ¹ FW). At the flowering stage, NDAPAS at 0.2% resulted in the highest RLWC (93.0%) and soil moisture (17.9%), with reduced proline (33.0 µg g⁻ ¹ FW), FAA (2.1 µg g⁻ ¹ FW), and TSS (22.8 µg g⁻ ¹ FW). Foliar sprays also improved chlorophyll fluorescence parameters (φP₀, φE₀, ψ₀, δR₀, and performance index) showing better photosynthetic efficiency and stability of photosystem II under stress. Application of SWAS at 0.5% at the vegetative stage and NDAPAS at 0.2% at the flowering stage was the most effective for improving crop yields under deficit moisture stress.

Improving soil carbon quality and biological fertility through long-term nutrient management is essential for sustaining productivity, reducing input dependence and enhancing climate resilience in rainfed Vertisols. This study evaluated the effects of nine treatments including control, inorganic fertilisation (50 % RDF, 100 % RDF, RDF + Zn), organic amendments [farmyard manure (FYM) (50 % NFYM, sole FYM), crop residues (CR) (50 % NCR)] and integrated nutrient management (INMFYM, INMCR) on soil carbon pools, oxidisable carbon fractions, carbon management indices (CMI) and enzyme activities in a permanent manurial experiment. Soil organic carbon (SOC) ranged from 5.66 (control) to 11.19 g kg-1 (INMFYM), both in the cotton phase. Inorganic treatments enhanced soil inorganic carbon (SIC), suggesting an inverse relationship with organic inputs. Sole FYM enriched the very labile fraction, whereas INM enhanced the labile and less labile fractions and non-labile carbon was highest under RDF + Zn. CMI ranged from 136.7–307.1 and was highest under sole FYM. The 50 % NFYM recorded higher permanganate oxidisable carbon (POXC) and microbial biomass carbon (MBC) than 100 % RDF despite lower SOC, highlighting the importance of substrate quality. Enzyme activities were consistently lower in the cotton phase. Structural equation modelling indicated that SOC was associated with dehydrogenase activity indirectly through MBC, which mediated 86.5 % of this effect, whereas POXC was the primary driver of β-glucosidase (BGA) and cellulase activities (CA). These findings demonstrate that biological fertility in dryland Vertisols is governed by active, biologically accessible carbon pools rather than total SOC and that sustained organic and integrated inputs are essential for enhancing carbon quality and microbial enzyme function.

Efficient nitrogen (N) management remains a major challenge in wheat production, where low N use efficiency (NUE) contributes to reduced yields and environmental degradation. Although nano-urea has emerged as a promising complements to conventional urea, its optimal dose and integration with basal N applications under field conditions remain insufficiently explored. This study evaluated eight N management strategies combining basal N levels with foliar applications of NPPL liquid nano-urea, NPPL powdered nano-urea, and IFFCO nano-urea in a randomized block design [(N ₀ PK + 2 ml NPPL nano urea, N ₀ PK + 4 ml NPPL nano urea, N ₅₀ PK + 2 ml L ⁻¹ NPPL nano urea, N ₅₀ PK + 4 ml L ⁻¹ NPPL nano urea, N ₀ PK + 0.625 g L ⁻¹ NPPL powered nano urea, N ₅₀ PK + 0.625 g L ⁻¹ NPPL powered nano urea, N ₇₅ PK + 4 ml L ⁻¹ IFFCO nano urea and 100% Recommended Dose of Fertilizer (RDF), i.e., 150–60–50 kg N-P ₂ O ₅ -K ₂ O/ha)]. The results indicated that the N ₅₀ PK + 4 mL L ⁻¹ NPPL liquid nano-urea treatment produced wheat yield comparable to those obtained with N ₇₅ PK + 4 mL L ⁻¹ IFFCO nano-urea. However, yield under N ₅₀ PK + NPPL liquid nano-urea remained lower than the recommended dose of fertilizers (RDF), whereas N75PK + IFFCO nano-urea was statistically at par with the RDF. Biochemical assessments indicated that N ₅₀ PK + 4 ml L ⁻¹ NPPL liquid nano-urea enhanced grain quality and improved NUE more effectively than other treatments, whereas RDF produced superior morphological and physiological traits leading to maximum yield. These findings suggest that while nano-urea can enhance NUE and reduce potential N losses, achieving yields equivalent to RDF may require optimized basal N levels. Overall, the study provides new insights into dose optimization and the complementary role of nano-urea in sustainable nitrogen management for wheat production in the Indo-Gangetic Plains.

Efficient nitrogen (N) and phosphorus (P) management enhances crop yield while minimizing environmental impact. Nano-fertilizers are reported to ensure sustained nutrient release, optimize nutrient absorption and improve nutrient use efficiency, leading to higher crop productivity and profitability. A two year field trial was conducted under semi-arid conditions in India to evaluate the effect of foliar-applied nano-DAP on the growth, productivity, profitability and nutrient use efficiency of rainfed maize. The treatments comprised conventional fertilizers at varying N and P levels [0, 50, 75, and 100% recommended dose of N and P] with and without foliar application of nano-DAP. Application of 100% recommended NPK (90-45–45 N-P-K kg ha ^-1 ) through conventional fertilizers along with foliar sprays of nano-DAP (N ₁₀₀ P ₁₀₀ K+ nano-DAP) resulted in higher grain yield (3058 kg ha ^-1 ) and economic returns (US $ 473 ha ^-1 ). Notably, the N ₇₅ P ₇₅ K + nano-DAP treatment produced yield and economic returns comparable to those obtained with 100% recommended NPK, either alone or in combination with nano-DAP. This demonstrates that two foliar sprays of nano-DAP can reduce N and P inputs by 25% without compromising on yield or profitability. Higher agronomic use efficiency of N (26.9%) and P (48.4%), apparent recovery efficiency of N (42.6%) and P (11.3%) were also observed under N ₇₅ P ₇₅ K + nano-DAP. Furthermore, N ₇₅ P ₇₅ K + nano-DAP treatment reduced greenhouse gas (GHG) emissions by 24.5% and energy consumption by 15.4%, highlighting its potential for sustainable maize production with reduced environmental impact compared to N ₁₀₀ P ₁₀₀ K treatments.

The harsh climate, land degradation, and poor resources are the principal causes of low productivity in the rainfed areas. A field experiment was conducted during the rainy and winter seasons of 2010–2015 (6 years) on maize‐horsegram cropping sequence to study the effect of soil amendment with tank silt, integrated use of chemical fertilizers and organic manure, and biofertilizers application on productivity, profitability, and changes in soil properties in degraded Alfisols of southern India. A total of 12 treatments were applied viz., T ₁ = Control, T ₂ = Recommended dose of fertilizer (RDF), T ₃ = 75% RDF + Phosphate solubilizing bacteria (PSB) + Azotobacter (AZ), T ₄ = 75% RDF + Farm yard manure (FYM) @ 5 Mg ha ⁻¹ , T ₅ = 75% RDF + FYM @ 5 Mg ha ⁻¹ + PSB + AZ, T ₆ = 75% RDF + Tank Silt 30 Mg ha ⁻¹ (Once in 3 years), T ₇ = 75% RDF + Tank Silt 30 Mg ha ⁻¹ + PSB + AZ, T ₈ = 50% RDF + PSB + AZ, T ₉ = 50% RDF + FYM @ 5 Mg ha ⁻¹ , T ₁₀ = 50% RDF + FYM @ 5 Mg ha ⁻¹ + PSB + AZ, T ₁₁ = 50% RDF + Tank Silt 30 Mg ha ⁻¹ , T ₁₂ = 50% RDF + Tank Silt 30 Mg ha ⁻¹ + PSB + AZ. Significantly higher system yield (Mg ha ⁻¹ ) was observed in 75% RDF + tank silt + PSB + AZ (5.5) and 75% RDF + FYM + PSB + AZ (5.4) treatments compared to control and RDF. The performance of the maize crop during the rainy season, especially in the years with a higher number of dry spells, was better in the tank silt applied plots compared to the plots without tank silt application. The average maize yields under 75% RDF + tank silt + PSB + AZ were higher than the treatments 75% RDF + PSB + AZ and 75% RDF + FYM + PSB + AZ by 17.5% and 4.4%, respectively. Significantly higher uptake of N (100.9 kg ha ⁻¹ ), P (32.0 kg ha ⁻¹ ), and K (119.8 kg ha ⁻¹ ) in maize was found in 75% RDF + tank silt + PSB + AZ. Higher crop response ratio (CRR) was recorded in 50% RDF + tank silt with biofertilizers treatment (31.19 kg yield kg ⁻¹ nutrient applied). Higher partial factor productivity for NPK (PFPf) was observed in 50% RDF + tank silt with or without biofertilizers treatments (40.7 kg yield kg ⁻¹ fertilizer nutrients applied). Significantly higher gross return (₹49,535 ha ⁻¹ ), net return (₹32,519 ha ⁻¹ ) and B:C ratio (2.91) were observed in 75% RDF + FYM + PSB + AZ, which were very closely followed by 75% RDF + tank silt + PSB + AZ with ₹49,478 ha ⁻¹ , ₹32,212 ha ⁻¹ and 2.87, respectively. Addition of tank silt once in 3 years not only increased the soil available N, P, K contents (with maximum contents of 163, 19.9, and 173 kg ha ⁻¹ , respectively) under 50% RDF + tank silt with or without biofertilizers, but also increased their availability to plants, which was reflected in nutrient uptake by maize. Thus, tank silt soil amendment can be a viable option to improve system productivity in light‐textured poor soils of semiarid tropics.

Nitrogen (N) is a vital macronutrient for maize productivity, but significant losses under rainfed conditions limit its availability and yield potential. There is a need for energy-efficient and eco-friendly fertilizers along with improved agronomic practices to enhance nutrient use efficiency, crop productivity, and profitability. An experiment was conducted under semi-arid conditions in India in a single location to evaluate the economic and environmental performance of conventional fertilizers at varying nitrogen levels [0, 50, 75, and 100% recommended rate of nitrogen (RDN)] with and without nano-urea in rainfed maize. Application of 100% recommended NPK through conventional fertilizers along with nano-urea spray (N₁₀₀PK + nano-urea) recorded significantly higher yield (3,026 kg ha^-1) and economic returns (US $ 477 ha^-1). Notably, the N₇₅PK + nano-urea registered comparable yield over N₁₀₀PK + nano-urea and N₁₀₀PK, demonstrating that two foliar sprays of nano-urea could reduce nitrogen input by 25% without yield loss. Additionally, this approach reduced greenhouse gas (GHG) emissions by 25% and energy consumption by 14.9%, highlighting its potential for sustainable maize production. Though the results are encouraging it should be tested across crops and regions.