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The understanding of the impact of nitrogen (N) fertilization on the field water cycle and corresponding water use efficiency (WUE) is very important for optimizing fertilization rates and conserving stressed water resources. We modeled soil moisture dynamics of maize (Zea mays L.), finger millet (Eleusine coracana Gaertn.), and lablab [Lablab purpureus (L..) Sweet] plots using calibrated HYDRUS‐1D model on two experimental sites (rain‐fed and irrigated) for three seasons under different N treatments. The results indicate that the effects of N depended on plant specific properties such as N‐fixation and drought tolerance, and on plant available water content governed by soil structure and rainfall seasonal variability. Maize WUE of plots which received 150 kg/ha of urea (46 %$\%$ N) were 10–30 kg/ha/mm higher than plots which received none; likewise, millet that received 50 kg/ha of urea had a 7–10 kg/ha/mm higher WUE than control plots in both experiments. However, differences in water cycle components were noticeable between N treatments only in the rain‐fed experiment, where higher N levels led to around 60 and 30 mm higher transpiration, 30 and 20 mm lower evaporation, and 30 and 15 mm lower percolation per season for maize and millet, respectively. In 2018, which was the driest year, the difference in maize WUE between the high and low N treatments was only 1 kg/ha/mm, which corresponded with low actual to potential transpiration ratios (<50%$<\!50\%$). This indicates higher sensitivity of maize to water stress compared to the other crops. The results of lablab indicate a positive impact of N fertilization on WUE only under water‐limited conditions. Core Ideas: HYDRUS models calibrated and validated based on soil moisture of minimum three soil profiles per crop per treatment.Transpiration reduction was calculated as a proxy for water stress and used to distinguish between nitrogen (N) and water stress effect.Favorable soil conditions such as good pH and water availability appear to minimize N effect on field water cycle.Precipitation amounts and plant‐specific properties interact to determine how N affects water balance and water use efficiency. [ABSTRACT FROM AUTHOR]

Rice–wheat production in the Indo-gangetic plains (IGPs) of India faces major concerns such as depleting resources, rice residue burning, excessive fertilizer use, and decreasing nitrogen use efficiency. These issues threaten sustainable crop production in the future. Therefore, a field study was conducted during the winter seasons of 2020–21 and 2021–22 to evaluate the effect of combined conventional and nano fertilizers on nitrogen application just before or after irrigation to improve wheat productivity, profitability and NUE under conservation tillage. The study evaluated eight treatment combinations of nitrogen application through conventionally applied urea (46% N) and foliar applied nano urea (4% N) under zero tillage with rice residue retention. Results revealed that growth, physiological indices, yield, and quality parameters were enhanced with the application of 150 kg N/ha in three equal splits as basal and just before 1st and 2nd irrigation alone (T2) or along with a spray of nano urea (T5) compared to other treatments. T5 recorded 7.2%, 8.5%, and 7.8% more plant dry matter, number of tillers, and grain yield, respectively, over the conventional practice of applying 150 kg N/ha in three equal splits as basal and 7–10 days after 1st and 2nd irrigation (T3, farmers practice). Although, T2 showed similar results to T5, T5 recorded significantly higher gross ($2542/ha) and net returns ($1279/ha) than the other treatments. However, the benefit–cost ratio of T2 and T5 was same (2.01). A significant and positive correlation coefficient between grain yield and physiological parameters such as CCI and NDVI confirmed that increasing the nitrogen dose enhanced the chlorophyll content, greenness, and plant vigor. Based on the results, it can be concluded that applying 150 kg N/ha in three equal splits as basal and just before 1st and 2nd irrigation under conservation agriculture, along with a single spray of nano urea (4% N) at 60–65 days after sowing, can improve growth, yield attributes, wheat yield, and NUE compared to farmers practice (T3) in India. [ABSTRACT FROM AUTHOR]

Rice–wheat production in the Indo-gangetic plains (IGPs) of India faces major concerns such as depleting resources, rice residue burning, excessive fertilizer use, and decreasing nitrogen use efficiency. These issues threaten sustainable crop production in the future. Therefore, a field study was conducted during the winter seasons of 2020–21 and 2021–22 to evaluate the effect of combined conventional and nano fertilizers on nitrogen application just before or after irrigation to improve wheat productivity, profitability and NUE under conservation tillage. The study evaluated eight treatment combinations of nitrogen application through conventionally applied urea (46% N) and foliar applied nano urea (4% N) under zero tillage with rice residue retention. Results revealed that growth, physiological indices, yield, and quality parameters were enhanced with the application of 150 kg N/ha in three equal splits as basal and just before 1st and 2nd irrigation alone (T2) or along with a spray of nano urea (T5) compared to other treatments. T5 recorded 7.2%, 8.5%, and 7.8% more plant dry matter, number of tillers, and grain yield, respectively, over the conventional practice of applying 150 kg N/ha in three equal splits as basal and 7–10 days after 1st and 2nd irrigation (T3, farmers practice). Although, T2 showed similar results to T5, T5 recorded significantly higher gross ($2542/ha) and net returns ($1279/ha) than the other treatments. However, the benefit–cost ratio of T2 and T5 was same (2.01). A significant and positive correlation coefficient between grain yield and physiological parameters such as CCI and NDVI confirmed that increasing the nitrogen dose enhanced the chlorophyll content, greenness, and plant vigor. Based on the results, it can be concluded that applying 150 kg N/ha in three equal splits as basal and just before 1st and 2nd irrigation under conservation agriculture, along with a single spray of nano urea (4% N) at 60–65 days after sowing, can improve growth, yield attributes, wheat yield, and NUE compared to farmers practice (T3) in India. [ABSTRACT FROM AUTHOR]

Optimizing nitrogen (N) inputs is crucial for maximizing wheat yield and ensuring environmental sustainability. Wheat's economic significance in India calls for a comprehensive evaluation of its ecological implications to develop a resilient production system. This study aimed to identify and evaluate ten wheat cultivars for their yield and N-use efficiency under varying nitrogen inputs (control (N0), half of the recommended nitrogen (N75), and the recommended nitrogen (N150)) using the surface application of neem-oil-coated urea. All N inputs were applied in three splits, basal, crown root initiation, and tillering stages, and an experiment was conducted in a split-plot design. The application of N150 gave the highest dry matter accumulation (DMA) at harvesting stage (AHS) (871 g m−2), seed/spike (60), grain yield (GY = 7.4 t ha−1), straw yield (SY = 8.9 t ha−1), harvest index (HI = 45.2%), protein (12.5%), and total uptake of N (TUN) (223 kg ha−1) by the cultivar 'HD 3249', being closely followed by the cultivar 'HD3117'. Six cultivars ('HD 3298', 'HD 3117', 'HD 3249', 'PBW 550', 'HD 3086', 'HD 2967') out of the ten cultivars evaluated responded well to different input treatments with respect to the grain yield efficiency index (GYEI ≥ 1). Regarding N input, N75 and N150 recorded the highest increases in plant height, AHS (16.5%; 21.2%), dry matter accumulation (DMA) at 30 days after sowing (DAS) (37.5%; 64%), DMA-60 DAS (42%; 53%), DMA-90 DAS (39.5%; 52.5%), TILL-30 DAS (19.8%; 26.4%), TILL-60 DAS (33.3%; 44%), TILL-90 DAS (37.2%; 47.2%), seed/spike (8%; 10%), 1000-grain weight (7.8%; 12.2%), and protein content (23.3%; and 33%) when compared with N0. Furthermore, the application of N75 and N150 improved GY (72.1%; 142.6%), SY (61.1%; 110.6%), BY (65.5%; 123%), and HI by 4.4% and 9%, respectively, over N0. Nitrogen addition (N75 and N150) also significantly increased total nitrogen uptake (104.7%; 205.6%), respectively, compared to N0. The correlation analysis revealed a positive association among most of the crop parameters. Overall, our research results suggest that the cultivars 'HD 3249' and 'HD 3117' have the potential to be effective options for improving N utilization efficiency, grain yield, and GYEI in North-West India. [ABSTRACT FROM AUTHOR]

Soil nitrogen (N) distribution and crop utilization are closely related to fertilizer management and crop productivity. The present study, based on 47-year fertilizer focused on a cropping system (maize-wheat) based budgeting of N which is necessary to identify its sources and losses to improve fertilizer use efficiency, crop productivity, and environmental sustainability. Long-term application of fertilizer has a positive effect on soil TN (total nitrogen) and TOC (total organic carbon), which increased by 36–107% and 24–103%, respectively compared to control. Integrated application of fertilizer and farmyard manure registered 266% higher grain yield of maize-wheat over the control but the addition of 50% higher NPK than recommended NPK showed no yield advantage and reduced recovery of fertilizer N by 23% (maize) and 22% (wheat) relative to NPK. Accounting all the N inputs and outputs, NPK application (least N loss) has 49–85 kg ha−1 lower N loss compared to NP and N application, respectively. It has concluded that the long-term use of recommended and balanced fertilizer alone or in combination with FYM has the potential to improve N and C status of soil and its recovery by decreasing its loss, which increases the productivity of the maize-wheat system. [ABSTRACT FROM AUTHOR]

The performance of DNDC (DeNitrification-DeComposition) and RothC (Rothamsted Carbon model) in simulating soil organic carbon (SOC) storage in soils under rice (Oryza sativa L.) – wheat (Triticum aestivum L.), maize (Zea mays L.) – wheat and cotton (Gossypium hirsutum L.) – wheat cropping systems was evaluated on field and regional scale. Field experiments consisted of N, NP, NK, PK, NPK, FYM, N + FYM, NPK + FYM, and control (UF) treatments. DNDC and RothC over-estimated SOC storage by 0.35–1.16 Mg C ha−1 (6–21%) in surface layer with manure application, compared with inorganic fertilizer treatments by 1.01–1.16 Mg C ha−1 (14–18%). Although RothC only slightly over-estimated SOC stocks, DNDC provided a better match for measured versus simulated SOC stocks (R2 = 0.783*, DNDC; 0.669*, RothC, p <.05). Model validation on independent datasets from long-term studies on rice–wheat (R2 = 0.935**, DNDC; R2 = 0.920**, RothC, p <.01) and maize–wheat (R2 = 0.895** for DNDC and R2 = 0.967** for RothC, p <.01) systems showed excellent agreement between measured and simulated SOC stocks. On a regional scale, change in SOC storage under Scenario 1 (NPK) was significant up to 8 years of simulation, with no change thereafter. In Scenario 2 (NPK + FYM), DNDC simulated SOC storage after 10 years was 2.0, 0.4, and 1.4 Mg C ha−1 in three systems, respectively. Amount of C sequestered in silt + clay fraction varied between 0.31 and 0.97 kg C 10 years−1 (Mg silt + clay)−1 under Scenario 1, and between 0.78 and 2.67 kg C 10 years−1 (Mg silt + clay)−1 under Scenario 2. [ABSTRACT FROM AUTHOR]

Due to its lower water requirement, methane emission and soil degradation, a maize–wheat rotation (MWR) may be a more attractive alternative to rice–wheat rotation (RWR), in the upper Indo-Gangetic plains (IGP) of India. However, N2O emission from MWR needs to be quantified to propose management practices for N2O mitigation. A field experiment was conducted at the Indian Council of Agricultural Research-Indian Agricultural Research Institute (ICAR-IARI), New Delhi, to assess the impacts of various N sources on N2O emission and its mitigation from the MWR. Six treatments –N0 (control), urea, urea + farmyard manure (FYM), FYM, urea + nitrification inhibitor (NI) and neem oil coated urea (NOCU) were investigated during 2012–2014. Results show ranges of N2O-N emissions from MWR of 0.59–0.69, 1.82–1.86, 1.81–1.85, 1.71–1.77, 1.38–1.52, 1.57–1.61 during 2012–2013, and of 0.62–0.68, 1.86–1.90, 1.78–1.84, 1.72–1.76, 1.40–1.46, 1.52–1.60 during 2013–2014, for N0, urea, urea + FYM, FYM, urea + NI and NOCU treatments, respectively. The 2-year pooled N2O-N emission of MWR decreased by 23% in urea + NI and by 16% in NOCU with higher grain yield as compared to conventional urea application. Application of FYM with urea and FYM alone also reduced N2O-N emission; however, the grain yields of these treatments were decreased. Thus, the study suggests that the application of NOCU and NI with urea can mitigate N2O-N emissions from the maize and wheat crops. Hence, the use of NOCU and application of NI with urea could be a better option to mitigate N2O-N emissions from MWR of the upper IGP of India. [ABSTRACT FROM AUTHOR]

A comprehensive long-term study (2006–2010) was undertaken to develop a balanced and integrated nutrient supply system for sunflower-based cropping sequence considering the efficient utilization of residual and cumulative soil nutrient balance along with added fertilizers by the crops grown in rotation. The fertilizer application was done in potato and sunflower while greengram was raised as such on their residual effect. Significant response in yield was observed with 150% of the recommended nitrogen, phosphorus and potassium (NPK) or inclusion of farmyard manure (FYM) with the recommended NPK in the cropping sequence indicating 6.2–7.0% gain in system productivity over the existing recommendations. Each additional unit of P and K nutrition prompted system productivity by 18.9 and 11.0 kg kg−1of applied nutrient, respectively. Apparent yield decline was observed in K and PK omission plots to the extent of 15.8 and 27.4% in potato, 10.5 and 23.9% in sunflower and 4.2 and 8.3% in greengram, respectively, compared to the recommended fertilization. The superiority of the FYM along with the recommended NPK (potato/sunflower) was evident on the overall profitability and sustainability of the system, highlighted by the significantly higher productivity (7.16 t SFEY ha−1), sustainability yield index (SYI; 0.76), production efficiency (PE; 27.85 kg SFEY ha−1day−1) and net returns (2520 USD ha−1) with a B:C ratio of 2.91. Apparent change in potassium permanganate (KMnO4)-N was negative in all the treatments while N and P balance was positive with 150% NPK fertilization. Nutrient uptake exceeded the replenishment with 100% NPK application and maintained net negative soil nutrient stock for all the primary nutrients, indicating the need for revalidation of the existing recommendations in the system perspective. Conspicuous improvement in residual soil fertility in terms of maximum buildup of soil organic carbon (14%) and enhancement in soil KMnO4-N (4.2%), Olsen-P (19.4%), ammonium acetate (NH4OAc)-K (5.8%) and dehydrogenase enzyme activity (44.4%) was observed in FYM-treated plots over the initial values. The study suggested that the inclusion of legumes and FYM application with the recommended NPK in potato-sunflower cropping sequence will sustain the system’s productivity through the efficient use of nutrients, enhanced microbial activity and improved soil health while combating escalating prices of fertilizers as well as environmental issues in the Indo-Gangetic plains of India and similar environments. [ABSTRACT FROM PUBLISHER]

Recent market slump in rice, less rainfall during monsoon, high temperature and scarcity of water during dry season leads to lower grain yield and less profit from rice cultivation in India. Farmers' grow upland crops like chickpea ( Cicer arietinum), greengram ( Vigna radiate), mustard ( Brassica nigra), corn ( Zea maize), pigeonpea ( Cajanus cajan), potato ( Solanum tuberosum), sunflower ( Helianthus annuus) etc. along with rice ( Oryza sativa) during the dry season. However, knowledge of greenhouse gas (GHG) emission from these rice based cropping systems is very limited. In the present study four rice based cropping systems was studied along with rice-rice rotation system as control in respect of GHG emission, yield potential and economic feasibility. Conventional plantation and fertilizer application methodology was followed for each crop. Methane (CH) and nitrous oxide (NO) flux from field plots were studied with conventional closed chamber method using gas chromatograph. CH flux was recorded highest from rice-rice rotation plots (304.25 kg ha). NO flux was recorded 1.02 kg ha from rice-rice rotation system during wet season. However, during wet season, higher NO flux (1.93 kg ha) was recorded from rice-potato-sesame rotation plots. Annual NO flux was also recorded significantly low (3.42 kg ha) from rice-rice rotation plots and high (6.19 kg ha) from rice-chickpea-greengram rotation plots. Significantly lower annual grain yield was recorded from rice-rice rotation plots (9.25 Mg ha) whereas it was 18.84 Mg rice eq ha from rice-potato-sesame rotation system. The global warming potential (GWP) of rice-rice rotation system was recorded significantly high (8.62 Mg CO ha) compare to plots with different rice based cropping systems. Computing all C-emission from cradle-to-grave, highest total C-cost was recorded from the rice-rice rotation system ($62.00 ha). We have made an attempt to calculate the C-credit of different rice based cropping systems by considering the difference of C-cost with control. The study suggests that the rice-potato-sesame is most sustainable among different cropping system studied in terms of economic profit ($1248.21 ha) and C-credit ($38.60 ha). The result of the study may be limited to the study region; however, the study has potential use in respect to the development of agriculture practice for adaptation to climate change. [ABSTRACT FROM AUTHOR]