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Maize (Zea mays L.), a multi-utility cereal crop, has a high requirement for nitrogen (N). However, conventional N application methods fail to achieve potential yield and contribute to environmental pollution. Thus, a 2-year (2022 and 2023) field investigation was conducted to understand the effect of sub-surface drip-fertigation (SSDF) and legume residue incorporation (3 t ha−1) on improving maize yield, uptake, remobilization, and use-efficiency of N. Four N levels, viz., 0, 50, 75, and 100% recommended dose of N (RDN) applied in 3-splits (3S) and 4-splits (4S), were compared with conventional maize cultivation, fertilized with 150 kg N ha−1 (CMC-N150). Variable N fertigation with SSDF significantly affected the dry matter (DM) and N remobilization from leaves towards kernel; at lower doses of N maize tended to mobilize higher DM and N towards kernel. Better growth, higher nutrient uptake, and better remobilization efficiency of DM/N led to higher grain yield under 75% RDN (19–23% increase) and 100% RDN (20–25% increase) sub-surface drip-fertigated, compared to CMC-N150. Using 50% RDN through SSDF yielded grain on par with CMC-N150, thus saving 50% N. Moreover, applying N in 4-splits (4S) gave 3–5% yield advantage over 3-splits. Partial factor productivity of N (PFPN) and agronomic N-use efficiency (AEN) of different SSDF treatments increased by 18–100% and 40–99%, respectively over CMC-N150. Greengram residue incorporation improved maize yield by 5–8%, PFPN by 4–5% over no-residue incorporation. Overall, there was a 25–50% N economy with concomitant yield improvement under SSDF over conventional N management. The SSDF coupled with legume residue incorporation could be a promising technology for enhancing N-use efficiency globally; however, it needs policy support for adoption in the producer's field. [ABSTRACT FROM AUTHOR]

Estimating surface runoff from an ungauged as well as gauged watersheds is vital for its planning besides construction of different water conservation structures. An attempt was made in this study to estimate the surface runoff potential of the Gambhir watershed using geospatial techniques and the natural resources conservation service-curve number (NRCS-CN) method. The land use/land cover (LULC) map was generated using Sentinel-2A satellite images with a 10-m spatial resolution. To estimate the curve numbers and calculate surface runoff, the hydrologic soil group (HSG) map and the LULC map were overlaid in a geographic information system (GIS) environment. The average annual runoff depth was computed to be 248 mm in response to an average annual rainfall depth of 658 mm acquired from daily rainfall data of 11 years (2007 to 2017). Moreover, the spatial variability map of runoff indicated a variation of 136 to 321 mm in the study watershed. Nonetheless, the study indicated that 18% of the watershed area had high runoff potential and 54% of the region has moderate to high potential for runoff generation. Such an investigation employing the NRCS-CN and geospatial techniques would assist in the delineation of areas having varying runoff generation potential, leading to the targeting and construction of water harvesting structures. [ABSTRACT FROM AUTHOR]

Burgeoning population growth and subsequent demand for freshwater, besides competition among irrigation, domestic, and industrial sectors, coupled with a changing climate, have necessitated prudent and effective management of water resources. Rainwater harvesting (RWH) is considered one of the most effective strategies for water management. However, the location and design of RWH structures are essential for proper implementation, operation, and maintenance. An attempt has been made in this study to locate the most suitable site for RWH structure and design using one of the robust multi-criteria decision analysis techniques, viz. analytic hierarchy process, using geospatial tools in the Gambhir watershed, Rajasthan, India. High-resolution Sentinel-2A data and a digital elevation model of the Advanced Land Observation Satellite were used in this study. Five biophysical parameters, viz. land use and land cover, slope, soil texture, surface runoff, and drainage density, were considered to identify suitable locations for RWH structures. It was observed that runoff is the prime factor in determining the location of RWH structures compared to other parameters. It was revealed that 75.54 km2 (13% of the total area) was very highly suited for the construction of RWH structures, while 114.56 km2 (19%) was highly suitable. A total of 43.77 km2 (7%) of land was determined to be unsuitable for the construction of any type of RWH structure. Farm ponds, check dams, and percolation ponds were suggested for the study area. Furthermore, Boolean logic was used to target a particular type of RWH structure. The study indicated that a total of 25 farm ponds, 14 check dams, and 16 percolation ponds can be constructed at identified locations in the watershed. Water resource development maps of the watershed generated using an analytical approach would be useful for policymakers and hydrologists for targeting and implementing RWH structures in the study watershed. [ABSTRACT FROM AUTHOR]

Direct-seeded rice (Oryza sativa L.) (DSR) supported by conservation agriculture (CA)-based crop management practices is perceived to address the challenge of producing more rice grain with less water. DSR is endowed with multiple benefits/advantages over transplanted puddled rice (TPR) through savings in labour (40-45%), water (30-40%), fuel/energy (60-70%), and reductions in greenhouse gas emissions. It can be an economic alternative to TPR, but the performance of CA-based no-till and residue retained DSR has been hardly studied. Therefore, this field experiment consisting of eight treatments was designed in the sixth year of a continuing experiment under CA-based rice-mustard cropping system to estimate and analyse water budgeting in rice. Results revealed that, in the 0-15 cm soil layer, both DSR and TPR plots showed similar soil moisture content (SMC) values at initial, developmental, mid-season, and late-season periods. However, the overall SMC in a triple zero-till system that constituted mungbean residue (MBR) + zero-till DSR (ZT DSR) − rice residue (RR) + zero-till mustard (ZTM) − mustard residue (MR) + summer mungbean (SMB) treatment was 9.7 and 10% in soil surface, and in 15-30 cm soil layer, 32 and 12.6% higher than that in TPR − ZTM and TPR − CTM (conventional till mustard) treatments, respectively. Irrigation water requirment, including effective rainfall, was the highest during the mid-season (380.2 mm), followed by the initial stage (312.9 mm). The total amount of irrigation water applied to DSR plots was 924.3 mm against 1441.4 mm in TPR plots, indicating a 517 mm water saving. The amount of water used for puddling and ponding in TPR was 135 and 96 mm, respectively. The best treatment (MBR + ZTDSR − RR + ZTM-MR + SMB) showed a deep percolation of 5.8 mm day−1 that was 26% lower than the highest deep percolation (7.8 mm day−1) observed in TPR-CTM. Thus, a DSR crop under the triple zero-till system with retention of crop residues for three seasons can be recommended for attaining higher crop and water productivity. An extrapolation of these results revealed that, by adoption of this technology, 60060 Mm3 of water can be saved which can irrigate 6.72 Mha additional rice areas in the entire IGP (Indo-Gangetic Plains; total area under rice-wheat cropping system is 10.5 Mha). This may also lead to the mitigation of climate change effects. This practice can be adopted in the irrigated rice-growing belts of the North-western IGP of India and in similar agro-ecologies of the tropics and sub-tropics. [ABSTRACT FROM AUTHOR]

Use of perennial grasses as vegetative barriers to reduce soil erosion from farm and non-farm lands is increasing world-over. A number of perennial grasses have been identified for their soil conserving properties, but their effectiveness varies with location and method of planting. Installing vegetative barriers in combination with suitable mechanical measures, like bunds or trenches or both, on the appropriately spaced contours may enhance their conservation potential. Hence, the effect of vegetative barriers, viz., sambuta ( Saccharum spp.)-a local grass, vetiver ( Vetiveria zizanioides) and lemongrass ( Cymbopogon citratus) planted in combination with trench-cum-bund, on runoff, soil loss, nutrient loss, soil fertility, moisture retention and crop yield in the rainfed uplands, was studied in Kokriguda watershed in southern Orissa, India through 2001-2005. However, runoff, soil and nutrient losses were studied for 2002, 2003 and 2004 only. Analysis of the experimental data revealed that on a 5% slope, the lowest average runoff (8.1%) and soil loss (4.0 Mg ha) were observed in the sambuta + trench-cum-bund treatment followed by vetiver + trench-cum-bund (runoff 9.8%, soil loss 5.5 Mg ha). Lemongrass permitted the highest runoff and soil loss. Further, the conservation effect of grass barriers was greater under bund planting than berm planting. Minimum organic C (50.02 kg ha), available N (2.49 kg ha) and available K (1.56 kg ha) loss was observed under sambuta with bund planting. The next best arrester of the soil nutrients was vetiver planted on bund. Significantly better conservation of nutrients under sambuta and vetiver resulted in the soil fertility build-up. Soil moisture content was also higher in the sambuta and vetiver than lemongrass treated plots. Increase in the yield of associated finger millet ( Eleusine coracana (L.) Gaertn.) due to vegetative barriers ranged from 18.04% for lemongrass to 33.67% for sambuta. Further, the sambuta and vetiver treated plots produced 13.23 and 11.86% higher yield, respectively, compared to the plots having lemongrass barrier (1.17 Mg ha). Considering the conservation potential, and crop yield and soil fertility improvements, the sambuta barrier with trench-cum-bund is the best conservation technology for treating the cultivated land vulnerable to water erosion. Farmers also showed greater acceptance for the sambuta barrier as it is erect growing and available locally. Vetiver with-trench-cum bund can be the second best option. [ABSTRACT FROM AUTHOR]