Northwest Indo-Gangetic Plains Research Articles

Effect of Zero Tillage and Different Weed Management Practices in Direct Seeded Rice (Oryza sativa L.) in Indo Gangetic Plains: A Review

Millions of rural and urban residents depend on the rice-wheat cropping system of the Indo-Gangetic plains (IGP) for their food security and means of subsistence. About 18 million hectares (m ha) of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) are rotated across Asia, of which 13.5 m ha are in the Indo-Gangetic Plains (IGP) of India. This agricultural system’s viability is currently in jeopardy due to static yields of both wheat and rice and a decline in total factor productivity. The North West IGP's high input crop culture has allowed weeds to dominate the weed flora, including P. minor in wheat and Echinochloa crus-galli L. in rice. Farmers in North West India have largely used zero tillage for growing wheat, and recently, farmers in the eastern IGP have done the same. Perennial weeds in the Eastern Indo-Gangetic Plain, such Cynodon dactylon L. and Cyperus rotundus L. can occasionally be a nuisance under zero tillage. As an alternative to puddled transplanted rice, the focus is currently on dry direct-seeded rice and machine transplanting of non-puddled rice. As a result of changes in tillage, crop establishment techniques, water use, and weed control brought on by the switch from transplanted rice to direct seeded rice, weed composition and diversity frequently vary. In nations where DSR is frequently used, weedy rice has become a significant concern. Using the Zero Tillage DSR system, certified seed, cultivars that are weed-competitive, stale seedbed procedures, living mulches, and chemical and biological weed control might change weed-crop competition in the crop's favour. However, more research on emergence characteristics and mulching effects of different crop residues on key weeds under zero tillage, cover cropping, and breeding crops for weed suppression will strengthen nonchemical weed management programs. In this review, we examine the extent of weed infestation, weed flora shift and the non-chemical alternative weed management in DSR.

Delayed sowing and its ramifications: biophysical, yield and quality analysis of wheat cultivars in the northwest Indo-Gangetic plains.

The continuous cultivation of rice-wheat in the same field is a key element of double-cropping systems in the Indo-Gangetic plains. Yields of such cropping systems are increasingly challenged as climate change drives increases in temperature, terminal stress and uneven rainfall, delaying rice harvesting and subsequently delaying sowing of wheat. In this paper, we evaluate the optimum sowing dates to achieve high grain yield and quality of wheat cultivars in northwest India. Three cultivars of wheat, HD-2967, HD-3086 and PBW-723, were sown on three different dates at the research farm of ICAR-IARI, New Delhi, to generate different weather conditions at different phenological stages. Different biophysical attributes, photosynthetic rate, stomatal conductance and transpiration rate, were measured at different phenological stages. Yield and grain quality parameters such as protein, starch, amylopectin, amylose and gluten were measured in different cultivars sown on different dates. Biophysical parameters were found to be higher in timely sown crops followed by late-sown and very late-sown crops. Further, the different sowing dates had a significant (P < 0.05) impact on the grain quality parameters such as protein, starch, amylopectin, amylose and gluten content. Percentage increases in the value of starch and amylose content under timely sown were ~7% and 11.6%, ~5% and 8.4%, compared to the very late-sown treatment. In contrast, protein and amylopectin contents were found to increase by ~9.7% and 7.5%, ~13.8% and 16.6% under very late-sown treatment. High-temperature stress during the grain-filling periods significantly decreased the grain yield. Reduction in the grain yield was associated with a reduction in starch and amylose content in the grains. The protein content in the grains is less affected by terminal heat stress. Cultivar HD-3086 had higher growth, yield as well as quality parameters, compared to HD-2967 and PBW-723 in all treatments, hence could be adopted by farmers in northwest India. © 2024 Society of Chemical Industry.

Phenotyping in Rye Landrace and Regeneration Frequency Study in Wheat × Rye F1 Hybrid Seeds

The present research aimed to study the phenotyping characterization of a high-altitude Himalayan rye landrace and its crossability with wheat genotypes and investigate the regeneration frequency of wheat × rye F1 hybrid seeds. The study was conducted during the rabi season of 2022-2023 at the Agriculture Research Farm, Department of Plant Breeding and Genetics, Lovely Professional University, Phagwara, Punjab. The phenotypic characterization of the Himalayan rye landrace revealed several adaptive traits that were found suitable for cultivation in the northwest Indo-Gangetic plains. Furthermore, the study investigated the crossability of the Himalayan rye landrace with various wheat genotypes, including 4 genotypes of bread wheat HD2967, UNNAT 343, WH1105, and PBW502 and 4 genotypes of durum wheat PDW291, PDW274, PBW34, and WHD943. Among the germination percentage of all 8 genotypes, 4 in Bread wheat and 4 in Durum wheat was observed. Due to its self-incompatibility, Rye cannot be used to develop inbred lines directly. However, the doubled haploid approach can produce inbred lines in the rye, facilitating the extension of genetic bases and introducing alien chromatin to identify stress tolerances.

Evaluating the connectivity of the Yamuna and the Sarasvati during the Holocene: Evidence from geochemical provenance of sediment in the Markanda River valley, India

In the northwest Indo-Gangetic plains, the linkage of the Ghaggar-Hakra paleochannel with the Sarasvati River of early Indian literature and the Harappan (or Indus) civilization poses an important case for understanding drainage reorganization and human-landscape interactions. Among the major paleochannels of the Ghaggar-Hakra, sediment provenance studies on the paleo-Sutlej branch show its connectivity with the Sutlej catchment during the Holocene. However, evaluation of the role of fluvial morphodynamics on the Harappan settlements remains restricted because of limited effort to identify drainage reorganization of the paleo-Yamuna and its connectivity to the Ghaggar-Hakra paleochannel. Here we focus on the sediment deposits in the Markanda Valley, upstream of the northernmost purported paleochannel (Y1) of the river Yamuna, to explore the possible connectivity of the Yamuna catchment with the Ghaggar-Hakra paleochannel through Y1. We analyzed sediment samples from fan surfaces, fluvial terraces, and the modern riverbed for trace element and Sr-Nd isotope geochemistry to identify source signatures. Chronology of the samples, available through Singh et al. (2021), shows aggradation of the fan (57.7 ka) and T-1 to T-5 fluvial terraces during 13.1 to 6.0 ka, and deposition of paleoflood sediment during 3.9–3.8 ka. Results of provenance analysis suggest that sediment in the Markanda Valley was primarily derived from the silicate rocks of the Subathu-Dagshai-Kasauli Formations and the Siwalik Group of the Sub-Himalayas, thus implying that the river Yamuna was not connected to the ancient Ghaggar-Hakra river system (the Sarasvati) through the paleochannel Y1 during the Holocene. The Late Holocene sediment in the Ghaggar-Hakra plains (<4.5 ka), like the sediment in the Markanda Valley, was derived from the sub-Himalaya and transported through Y1, whereas the depositional pathway for the older sediment (>4.5 ka), having sources in the Himalayan hinterland, was likely the southernmost paleochannel (Y2) of the Yamuna.

Conservation Tillage and Nutrient Strategies Enhances Crop-Water Productivity and Economic Profitability of Wheat (Triticum Aestivum L)

Decline in soil fertility is one of the major constraints to sustainable crop production and profitability. To meet the increasing demand for the growing population the issue of low soil fertility needs to be addressed moreover, excessive pumping of groundwater over the years to meet the high irrigation water requirement of rice-wheat system has resulted in over exploitation of groundwater in the Indo-Gangetic plains (IGP) of India. Replacement of traditional wheat cultivation practices under conservation agriculture (CA) based management (tillage, and crop establishment management) practices are required to promote sustainable agriculture. Furthermore, inefficient nutrient management practices are responsible for low crop yields and nutrient use efficiencies in wheat under rice-wheat cropping system (RWCS). A field experiment was conducted at Crop Research Centre of Sardar Vallabhbhai Patel University of Agriculture &amp; Technology, Meerut (U.P.), India to evaluate the effects of tillage and crop establishment (TCE) methods, and nutrient management practices on crop yields, water productivity and profitability of wheat under RWCS. The main plot treatments included four combinations of TCE [Furrow irrigated raised beds (FIRB), Roto tillage (RT), Reduced tillage (RTW) and conventional tillage (CT), with six nutrient management practices [N1 Control, N2 100% Recommend Dose of Fertilizer, N3 100% RDF + NPK consortia + Bio-stimulant, N4 75% RDF + NPK consortia + Bio-stimulant, N5 100% RDF + NPK consortia + Bio-stimulant + NPK (18:18:18) spray after II irrigation, and N6 and 75% RDF + NPK consortia + Bio-stimulant + NPK (18:18:18) spray after II irrigation]. Crop water productivity and net returns under FIRB were significantly increased by 11.7% and 13.8% compared to CT respectively, during year of experimentation. Study showed that conservation agriculture based sustainable practices (FIRB) and nutrient strategies 100% RDF + NPK consortia + Bio-stimulant + NPK (18:18:18) spray after II irrigation approach provided opportunities for enhancing crop and water productivity, and profitability of wheat crop in North-West IGP of India. Treatments with N and conservation agriculture were the most profitable. A combined use of conservation agriculture and organic and chemical fertilizers is the best bet for increasing, wheat crop yield and associated return on investment.

Impact of long term conservation agriculture on soil quality under cereal based systems of North West India

Soil quality is of utmost essential for yield sustainability of intensive cereal based cropping system in North West Indo Gangetic plains of India. Hence, we evaluated long-term (10 years) effect of conservation agriculture (CA) practices on soil quality improvement under six different cropping scenarios (Sc), i.e. Sc1-represented by transplanted puddled rice (TPR) followed by conventional tilled broadcasted wheat (CT-wheat) with residue removal, Sc2-TPR rice followed by zero tillage (ZT) wheat and ZT-mung bean with partial residue retention, Sc3-direct seeded rice (DSR) followed by ZT-wheat and ZT-mung bean with full residue retention, Sc4-DSR is replaced by ZT-maize followed by ZT-wheat and ZT-mung bean, Sc5 and Sc6 were – Sc3 integrated with sub surface drip irrigation (SDI) and Sc4 + SDI, respectively. Soil samples were collected from 0 to 5, 5–15 and 15–30 cm soil depth from each scenario after harvesting of wheat in 2019. Results showed that, reduction in bulk density (BD), soil penetration resistance (SPR) and enhancement of water holding capacity and infiltration were associated with CA based scenarios (Sc3–Sc6). Scenario 3 recorded lowest BD of 1.39 and 1.58 g cm−3 at 0–5 and 5–15 cm soil depth, respectively. CA based Sc6 recorded highest infiltration rate (1.48 cm hr−1) and lowest was associated with Sc1 (0.5 cm hr−1). The enrichment of soil organic carbon (SOC) content, stock, available nitrogen and potassium was mainly confined to upper surface soil layer (0–5 cm). The SOC content and stock in CA based scenarios (average of Sc3 to Sc6) was 41–57 and 69–94% higher than Sc1 at 0–5 cm soil layer. Available nitrogen was increased by 23–50 and 64–98% and available potassium increased by 13–28 and 42–71% in 0–5 and 5–15 cm soil depth, respectively in CA based scenarios over Sc1. Similarly, microbial biomass carbon (MBC) and dehydrogenase (DHA) activity in top soil layer under CA based scenarios was increased by 177–195 and 67–107% over Sc1, respectively. The maximum SQI was registered with Sc6 (0.91) followed by Sc4 (0.89) and least was recorded in Sc1 (0.65) at 0–5 cm soil depth. Maize-wheat based cropping system recorded higher SQI over rice–wheat based cropping system. Sustainable yield index was strongly related with key soil quality indicators and also positively correlated with SQI. Thus our study suggests that CA based maize-wheat-mung bean cropping system should be recommended for better soil quality and yield sustainability in North West India.

Rice–wheat system in the northwest Indo-Gangetic plains of South Asia: issues and technological interventions for increasing productivity and sustainability

Puddled transplanted rice (Oryza sativa L.) followed by intensively tilled wheat (Triticum aestivum L.) (R–W) is the most predominant cropping system and the lifeline for billions of people in South Asia. The cultivation of R–W system requires high amounts of water, nutrients and energy, resulting in increased production costs and increased emissions of greenhouse gases. There are also increasing concerns of yield stagnation or decline in the R–W system, with increasing environmental footprints. Hence, the sustainability of the R–W system in South Asia, particularly in the northwest Indo-Gangetic Plains (IGPs), has been questioned and heavily debated. Based on the findings from peer-reviewed literature, this review aims to identify unsustainability issues and research gaps in the R–W system and propose possible solutions to mitigate those issues and technological interventions to close the research gaps. Among the unsustainability issues that the review has identified are declining crop, water and land productivity, deterioration of soil health, emissions of greenhouse gases due to intensive tillage and residue burning, deepening of groundwater levels and shift in weed flora and development of herbicidal resistance in crops. Potential solutions or technological interventions to mitigate the unsustainability issues include resource conservation technologies (RCTs) such as rice residue management, reduced tillage, laser land leveling, soil matric potential based irrigation scheduling, delayed rice transplanting, cultivation on permanent raised beds, direct-seeded rice (DSR), mechanical transplanting of rice and crop diversification with legumes. These interventions have the potential to reduce energy, water and carbon (C) footprints from the R–W system. Rice residue retention with Happy Seeder and adoption of zero tillage (ZT) for wheat establishment have significantly lowered the environmental footprints, with increased soil C sequestration due to additions of large amounts of plant-mediated C input. Residue mulching has helped increase root length of wheat by ~25% and root length density by ~40% below 15 cm depth, compared to no mulching. The Happy Seeder saved ~30% of irrigation water due to reduction of soil evaporation by ~42–48 mm through residue mulching. Crop cultivation on permanent raised beds is less energy-intensive and results in ~7.8–22.7% higher water use efficiency yet crop productivity in long run could be affected due to reduced root growth on beds. The puddled transplanted rice (PTR) established under wet tillage, however, can decrease the water percolation losses by 14–16% and crop water demand by ~10–25%, and it forms hard pan in soil plough (7–10 cm) layer due to increased soil bulk density. Water stagnation under continuously flooded PTR is the major source of methane emissions with serious environmental implications. Methane emissions from flooded rice can increase global warming potential by 18.1–27.6% compared to intermittently flooded rice with multiple aerations. The conventional tillage can favor the germination of grassy weeds in wheat, while the broad-leaved weeds increase under zero tillage. Zero tillage with mulch load conserved ~4.0% higher moisture due to ~2.3% lesser soil temperature and evaporated ~27.6% lesser than the conventional tillage. Delayed rice transplanting with short-duration variety has potential of saving of up to ~140 mm of irrigation water in the semiarid areas of NW IGPs. Although the DSR had lower yield potential than the PTR, it saved ~50% irrigation water. The laser land leveling technology saved ~30% irrigation water and ~25% electricity and had a yield advantage of ~4%, compared with PTR on un-leveled fields. The mechanical transplanted rice had higher grain yield and more water saving than the manual transplanting or DSR. The review demonstrates that a single technology may not be applicable everywhere and integrated approaches with the multiple criteria—productivity, economics, energy and environmental sustainability—would be required to address the unsustainability issues of the R–W system of the NW IGPs. There is a need to elucidate and disseminate various site- and context-specific RCTs appropriate for the region to address the unsustainability issues and challenges of the system. Sustainable R–W production technologies with reduced water, energy and C footprints are required for increased water and energy productivity and C sequestration for the NW IGPs of South Asia.

Chemical and isotopic characteristics of PM2.5 over New Delhi from September 2014 to May 2015: Evidences for synergy between air-pollution and meteorological changes

The capital city of India, New Delhi, is experiencing serious PM2.5 pollution in the form of recurrent hazy skies and smoky fog (SMOG) episodes in recent years. Besides source-emission strengths, frequency and time-spans of these air-pollution episodes are uncertain due to variable urban meteorological influences, preventing the formation of a cohesive policy to tackle air-quality degradation. About 70% mass of PM2.5 particle is composed of Carbon (C), Nitrogen (N), and Sulphur (S) and, hence, their mass concentrations along with their stable isotopic imprints (viz. δ13CPM2.5, δ15NPM2.5 and δ34SPM2.5) provide powerful tools to gain insights into complex aerosol chemistry. This study presents the aforementioned data generated for PM2.5 collected from New Delhi covering full post-monsoon, winter, and summer months of 2014–15. Temporal variability in the generated dataset was analyzed with variabilities in atmospheric concentrations of key gaseous species (NH3, NOx, and SO2) and meteorological indices. The highest PM2.5 concentrations were observed in winter months with enhanced aerosol N and S concentrations. Active biomass (crop-residue) burning in the northwest Indo-Gangetic Plains (IGP) appears to be the major source of aerosol TC for post-monsoon and winter months in addition to emission sources from the combustion of bio- and fossil- fuels. Aerosol TN contents appear to be largely impacted by ambient ammonia emissions, especially during winter. Aerosol TS contents could be manifested by emissions from coal combustion, road dust, and biogenic sulphur. Total C + N + S contents of PM2.5 showed significant negative correlations with surface solar radiation and air-visibility. Both δ15NPM2.5 and δ34SPM2.5 values show remarkable correlations with air-quality and meteorological parameters during winter months demonstrating considerable secondary cycling. Cluster analysis and concentrated weighted wind trajectories over New Delhi for the study-period showed ~64% and ~58% of air mass trajectories from the northwest (Punjab-Haryana) region during post-monsoon and winter months respectively.

Assessment and prediction of surface ozone in Northwest Indo-Gangetic Plains using ensemble approach

The earth’s surface ozone levels are becoming very significant due to their negative impact on human health, vegetation and climate. In this study, the methodology based on ensemble approach embodied linear and nonlinear behaviors was developed. It was applied for prediction of ozone concentration using dataset (2013–2016) of gaseous pollutants (O3, CO, NOx, MHC, TNMHCs) and meteorological variables as input variables. The daily O3 max/O3 min ratio of 10.9 marks the peculiar ozone pollution in the area. The fourteen prediction algorithms and their possible combinations of ensemble models were employed in this paper. Compared with individual models, the ensemble model approach showed an index of agreement of 0.91, the accuracy of 95.5% and mean absolute error of − 0.001 ppb between the predicted and observed diurnal cycle and daily averaged data of the year 2016 for benchmark analysis.

Deciphering the Factors for Nodulation and Symbiosis of Mesorhizobium Associated with Cicer arietinum in Northwest India

The compatibility between rhizobia and legumes for nitrogen-fixing nodules and the stages of root hair curling, formation of infection thread, and nodulation initiation have been vitally studied, but the factors for the sustainable root surface colonization and efficient symbiosis within chickpea and rhizobia have been poorly investigated. Hence, we aimed to analyze phenotypic properties and phylogenetic relationships of root-nodule bacteria associated with chickpea (Cicer arietinum) in the north-west Indo Gangetic Plains (NW-IGP) region of Uttar Pradesh, India. In this study, 54 isolates were recovered from five agricultural locations. Strains exhibited high exopolysaccharide production and were capable of survival at 15–42 °C. Assays for phosphate solubilization, catalase, oxidase, Indole acetic acid (IAA) production, and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity revealed that all the tested isolates possessed plant growth-promoting potential. Metabolic profiling using Biolog plates indicated that patterns of substrate utilization differed considerably among isolates. A biofilm formation assay showed that isolates displayed a nearly four-fold range in their capacity for biofilm development. Inoculation experiments indicated that all isolates formed nodules on chickpea, but they exhibited more than a two-fold range in symbiotic efficiency. No nodules were observed on four other legumes (Phaseolus vulgaris, Pisum sativum, Lens culinaris, and Vigna mungo). Concatenated sequences from six loci (gap, edD, glnD, gnD, rpoB, and nodC) supported the assignment of all isolates to the species Mesorhizobium ciceri, with strain M. ciceri Ca181 as their closest relative.

Enhanced Ozone Production in Ambient Air at Patiala Semi-Urban Site During Crop Residue Burning Events

The continuous in situ measurements of criteria pollutants (O3, CO and NOx) and meteorological variables were done at a semi-urban site (Patiala) of North-West Indo-Gangetic Plains (NW-IGP) for the years 2014 and 2015. The influence of meteorology on the levels of criteria pollutants was investigated on daily, monthly, seasonal and diurnal basis. The average rate of increase in O3, calculated to be 1.1 ppb h−1 and pollution index (daily O3 max/O3 min ratio), values (10.2) indicates remarkable ozone pollution. Ozone is negatively correlated (represented as r value) with its precursor gases CO (− 0.28) and NOx (− 0.32), as they get consumed in the photochemical production of ozone. The impact of meteorology on ozone production was positively correlated with SR (0.63), AT (0.49), MT (0.59) and WS (0.23) and negatively correlated with RH (− 0.83). Pre-, during and post-biomass burning periods were determined using Terra-MODIS images over the study area. Enhanced levels of ozone were recorded as 20 ppb and 15 ppb during daytime, respectively, for rice and wheat crop seasons, and 12 ppb during nighttime for both seasons. Ozone exceedance of 24 h national standard occurred on 50% and 8% of the sampling periods during wheat and rice crop residue burning, respectively. Ozone generation with its precursor gases was analyzed quantitatively.

Effect of conservation agriculture on stratification of soil organic matter under cereal-based cropping systems

ABSTRACTDegradation of soil quality caused by conventional tillage practices is a major concern for the sustainability of rice-wheat cropping systems in South Asian region. Therefore, suitable conservation agriculture (CA) practices are required. This study investigates the stratification and storage of soil organic carbon (SOC) and total nitrogen (TN) as affected by eight years of different CA practices in the North-West Indo-Gangetic Plains of India. There were four treatments: (1) conventionally tilled rice-wheat cropping system, (2) reduced-till CA-based rice-wheat-mungbean system, (3) no-till CA-based rice-wheat-mungbean system, and (4) no-till CA-based maize-wheat-mungbean system. The mean stratification ratio (SR) (i.e. a ratio of the concentrations of SOC and TN in the soil surface to those in a deeper layer) of SOC and TN for 0–5:5–10, 10–15, 15–20, 20–25 and 25–30 cm were found higher (> 2) under CA practices compared to intensive tillage-based conventional agricultural practice (< 2). No-till CA-based rice-wheat-mungbean system stored the highest amount of SOC (25.32 Mg ha−1) whereas reduced till CA-based rice-wheat-mungbean system stored highest amount of TN (3.21 Mg ha−1) at 0–30 cm soil depth. This study shows that CA stratifies SOC and TN and helps to enhance SOC sequestration and soil quality.

Productivity and economics of different cropping systems in relation to tillage, mulching and fertilizer management practices in north-western Indo-Gangetic Plains of India

Diversification and intensification of existing rice-wheat cropping system in north-west Indo-Gangetic Plains with suitable resource conserving practices is the key answer for increasing profitability. Keeping this in view, a field experiment was conducted at Ludhiana during 2014-15 and 2015-16 to study the effect of tillage, mulching and fertilizer management practices on productivity and economics of different cropping systems. The results showed that minimum tillage produced significantly higher economic yield of maize (Zea mays L.) (42.98 and 44.86 q/ha), wheat (Triticum aestivum L.) (47.57 and 48.30 q/ha), potato (Solanum tuberosum L.) (252.42 and 254.93 /ha), vegetable pea (Pisum sativum L.) (132.42 and 137.08 q/ha) and spring maize (64.88 and 66.55 q/ha). Significantly higher maize equivalent yield (4.6 and 3.5%), higher net returns (Rupees 153445 and 170803/ha) and B:C (1.33 and 1.43) was obtained under minimum tillage than conventional tillage. The productivity of maize-based cropping systems was significantly higher than conventional rice-wheat cropping systems. Maize-vegetable pea-spring maize produced 119 and 137% higher MGEY and higher net returns (Rupees 218738 and 259235/ha), while maize-potato-spring maize showed 82 and 74% higher MGEY over rice-wheat cropping systems. Organic manures (FYM) in conjugation with inorganic fertilizers (75% RDF + 25% N through FYM) resulted in comparable MGEY with inorganic fertilizer (100% RDF). Application of mulch along with fertilizer treatments resulted in significantly higher MGEY as compared to fertilizer treatments without mulch. Gross returns were higher under mulch with fertilizer treatments, while the B:C ratio under mulch with fertilizer treatments was less as compared to fertilizer treatments without mulch.

Conservation agriculture and precision nutrient management practices in maize-wheat system: Effects on crop and water productivity and economic profitability

Excessive pumping of groundwater over the years to meet the high irrigation water requirement of rice-wheat system has resulted in over exploitation of groundwater in the Indo-Gangetic plains (IGP) of India. Replacement of traditional rice with less water crops such as maize under conservation agriculture (CA) based management (tillage, crop establishment and residue management) practices are required to promote sustainable intensification. Furthermore, inefficient nutrient management practices are responsible for low crop yields and nutrient use efficiencies in MW system. A 3-year field experiment was conducted in farmer’s participatory strategic research mode at Taraori, Karnal, India to evaluate the effects of tillage and crop establishment (TCE) methods, residue management, mungbean integration, and nutrient management practices on crop yields, water productivity and profitability of MW system. The main plot treatments included four combinations of TCE, residue and mungbean integration [conventional tillage (CT), conventional tillage with mungbean (CT + MB), permanent bed (PB) and permanent bed with MB (PB + MB] with three nutrient management practices [farmer’s fertilizer practice (FFP), recommended dose of fertilize (RDF) and site specific nutrient management (SSNM)] using Nutrient Expert® as sub plot treatments. System productivity, water use efficiency (WUE) and net returns under PB + MB were significantly increased by 28.2–30.7%, 27.8–31.0% and 36.8–40.5% compared to CT respectively, during three years of experimentation. Integration of MB in MW system contributed 24.9 and 27.6% increases in system productivity and net returns compared with no MB, respectively. SSNM based nutrient management increased the mean (averaged across 3 yrs) system productivity, WUE and net returns of MW system by 13.4%, 13.3% and 15.3% compared with FFP, respectively. Study showed that conservation agriculture based sustainable intensification (PB + MB) and SSNM approach provided opportunities for enhancing crop and water use efficiency, and profitability of MW system in North-West IGP of India.

Evaluating alternatives to rice-wheat system in western Indo-Gangetic Plains: Crop yields, water productivity and economic profitability

Serious water deficits, diminishing profitability and deteriorating natural resources are threatening agricultural sustainability in many regions of South Asia. High water input and low water productivity of conventional irrigated rice–wheat (RW) systems has led to the depletion of surface water and ground waters in northwest India. Conservation agriculture (CA) practices with precision irrigation management and replacing rice with low water requiring maize crop may help to achieve sustainable crop production in the western Indo-Gangetic Plains (IGP) of India. A three-year field experiment was conducted to evaluate the effect of CA-based management (tillage, crop establishment, residue management mungbean integration), precision water management on crop and water productivity, and economic profitability in RW and maize-wheat (MW) systems. The treatments for RW systems included: i) conventional till rice-wheat with irrigation scheduling at critical growth stages (CTRW); ii) CTRW + mungbean (CTRW + MB); iii) Zero-till RW with residue retention (+R) scheduling precise irrigation (PI) based on soil matric potential approach (ZTRW + R + PI); and iv) ZTRW + MB + R + PI. A similar set of treatments was evaluated for MW systems, except the crops were established on raised fresh beds (FB) and permanent beds (PB). Treatment PBMW + MB + R + PI recorded 38% higher system productivity, saved 1660 mm of irrigation water, increased irrigation + rainfall water productivity (WPI+R,) by 270% and increased net returns by 84% compared to CTRW. ZTRW + MB + R + PI recorded 24, 41 and 37% (3 yrs’ mean) higher system productivity, WPI+R and net returns, respectively, compared to CTRW. System productivity was increased by 19 and 33%, WPI+R by 223 and 29% and net returns by 84 and 57% with ZTRW and PBMW compared to CTRW, respectively irrespective of MB integration and residue management. On average, inclusion of MB in cereal systems (RW/MW) contributed an 18% increase in system productivity and a 15% increase in net returns. CA based sustainable intensification of MW systems (PBMW + MB + R + PI) is a better alternative to RW system (ZTRW + MB + R + PI) as it provides opportunities for saving 79% of precious water, enhancing crop and water productivity by 12 and 145%, respectively along with high (34%) economic benefits thereby helping to arrest decline in ground water table in the North-West IGP of India.

Source region and sector contributions of atmospheric soot particle in a coalfield region of Dhanbad, eastern part of India

Black carbon (BC) aerosols affect the Earth's climate directly by interacting with the solar radiation and indirectly by modifying the lifetime and optical properties of clouds. However, our understanding of BC aerosols and their impacts on the climate are limited by lack of in situ measurements of BC, especially in the developing world. This study reports measurements of BC from Dhanbad, a coalfields area of eastern India, we analyze BC data at 370 and 880nm during 2013 to gain insight into the emission sources affecting the study area. Our analysis indicates significantly higher absorption at the lower wavelength (ultraviolet). We estimate that ~33% of BC at Dhanbad comes from biomass/biofuel combustion and the remaining 67% from the fossil fuel combustion. Higher concentrations of BC370nm (>12μgm−3) were observed when the air masses affecting Dhanbad originated far away in countries like Iran, Afghanistan, Pakistan, Oman, United Arab Emirates and passed over the Indo-Gangetic Plains (IGP) prior to arriving at the observation site. The source regions affecting BC880nm were localized over the IGP but BC880nm concentrations are 33% lower (~8μgm−3) than BC370nm. The cluster analysis showed that the largest fraction (35 and 29%) of the air masses arriving at Dhanbad passed through the boundary layer of the central IGP and north-west IGP region during the post-monsoon season. Average values of BC370nm (16.0 and 20.0μgm−3) and BC880nm (9.5 and 10.0μgm−3) in the IGP influenced air masses were significantly higher than those arriving from other source regions. The Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) model were applied to understand the relative importance of different sources affecting Dhanbad. The variability of observed BC mass concentrations was captured fairly well by WRF-Chem with minor deviations from the measured values. Model results indicate that anthropogenic emissions account for more than 75% of the surface BC at Dhanbad. Biomass burning contribution peaks in March–April and October–November but remains less than 25%. Long-range transport estimated in terms of inflow from domain boundaries does not affect BC concentrations at Dhanbad significantly.

Reducing Global Warming Potential through Sustainable Intensification of Basmati Rice-Wheat Systems in India

This study examines the effects of tillage, residue management and cropping system intensification through the inclusion of green gram on the performance of the rice-wheat (RW) system in NW India. We hypothesized that zero tillage (ZT) with residue retention provides a means of sustainably intensifying the RW system through lower production costs and higher economic profitability, whilst at the same time minimizing soil and environmental trade-offs. To test this hypothesis, we evaluated six combinations of tillage, residue management and green gram integration in RW rotation in northwest Indo-Gangetic Plains (IGP) of India. Treatments included in the study were: rice and wheat under conventional tillage (CT) with and without green gram (CTR-CTW, CTR-CTW+GG), both crops under zero-tillage (ZT) with and without green gram (ZTR-ZTW-R, ZTR-ZTW-R+GG) and both crops under ZT plus residues with and without green gram (ZTR-ZTW+R, ZTR-ZTW+R+GG). Based on two consecutive years of data, the net return from the RW system was significantly higher in the ZT than CT systems. Methane emissions were only observed under flooded conditions in CT rice plots; otherwise, emissions were negligible in all other treatment combinations. N2O emissions were dictated by N fertilizer application with no other treatment effects. Overall, ZT with residue retention resulted in the lowest global warming potential (GWP) ranging from −3301 to −823 kg CO2-eq ha−1 year−1 compared to 4113 to 7917 kg CO2-eq ha−1 year−1 in other treatments. Operational inputs (tillage, planting, and irrigation) and soil C sequestration had significant effects on total GWP. The water footprint of RW production system was about 29% less in CA-based system compared to CT-based systems. Our study concludes that ZTR-ZTW+R and ZTR-ZTW+R+GG in RW systems of northwestern IGP have the potential to be agronomically productive, economically viable with benefits also for the environment in terms of soil health and GHG emissions.

Crop residue degradation by fungi isolated from conservation agriculture fields under rice–wheat system of North-West India

In North West-Indo Gangetic Plains (NW-IGP) of India in situ burning of crop residues is practiced by majority of farmers’ which deteriorates soil and environmental quality. Fungi have the potential for lignocellulose degradation and can be used for the in situ decomposition of crop residues. Lignocellulose degrading fungal spp. were isolated and evaluated for the activity of lignocellulolytic enzymes. The lignocellulose degrading fungi were isolated by appearance of zone on carboxy methyl cellulose (CMC) agar media and tannic acid (TA) media. Carboxy methyl cellulase, filter paperase, cellobiase, xylanase and laccase activity were estimated in submerged, as well as solid state fermentation using a mixture of rice and wheat straw in the ratio of 4:1. rice–wheat straw as substrate. The residue left after solid state fermentation was evaluated for carbon/nitrogen ratio, dry mass loss, and loss of cellulose, hemicellulose and lignin. Selected potential isolates were further tested in pot experiment for their effect on wheat plants. The interaction among isolates was also studied. After primary screening, 19 out of a total of 72 fungal isolates were selected based on their enzymatic activity profile and potential to degrade lignocellulosic residues in submerged fermentation. Out of these 19 isolates, 11 were further selected based on their enzymatic secretions in solid state fermentation. All the 11 strains were identified morphologically. Four fungal isolates (RPW 1/3, RPW 1/6, RPWM 2/2 and RZWM 3/2) showed higher enzymatic activities and more loss of dry mass and cell wall constituents over the other isolates. These isolates were identified by ITS region sequencing as Aspergillus flavus, Aspergillus terreus, Penicillium pinophilum and Alternaria alternata. This study revealed that fungal isolates may be used for managing crop residues in conservation agriculture based rice–wheat system of NW-IGP to eliminate ill effects of residue burning.

Evaluation of the effects of mulch on optimum sowing date and irrigation management of zero till wheat in central Punjab, India using APSIM

Machinery for sowing wheat directly into rice residues has become more common in the rice-wheat systems of the north-west Indo-Gangetic Plains of South Asia, with increasing numbers of farmers now potentially able to access the benefits of residue retention. However, surface residue retention affects soil water and temperature dynamics, thus the optimum sowing date and irrigation management for a mulched crop may vary from those of a traditional non-mulched crop. Furthermore, the effects of sowing date and irrigation management are likely to vary with soil type and seasonal conditions. Therefore, a simulation study was conducted using the APSIM model and 40 years of weather data to evaluate the effects of mulch, sowing date and irrigation management and their interactions on wheat grain yield, irrigation requirement (I) and water productivity with respect to irrigation (WPI) and evapotranspiration (WPET). The results suggest that the optimum wheat sowing date in central Punjab depends on both soil type and the presence or absence of mulch. On the sandy loam, with irrigation scheduled at 50% soil water deficit (SWD), the optimum sowing date was late October to early November for maximising yield, WPI and WPET. On the clay loam, the optimum date was about one week later. The effect of mulch on yield varied with seasonal conditions and sowing date. With irrigation at 50% SWD, mulching of wheat sown at the optimum time increased average yield by up to 0.5tha−1. The beneficial effect of mulch on yield increased to averages of 1.2–1.3tha−1 as sowing was advanced to 15 October. With irrigation at 50% SWD and 7 November sowing, mulch reduced the number of irrigations by one in almost 50% of years, a reduction of about 50mm on the sandy loam and 60mm on the clay loam. The reduction in irrigation amount was mainly due to reduced soil evaporation. Mulch reduced irrigation requirement by more as sowing was delayed, more so on the sandy loam than the clay loam soil. There was little effect of mulch on irrigation requirement for late October sowings.There were large trade-offs between irrigation input, yield, WPET and WPI on the sandy loam with regard to the optimum irrigation schedule. Maximum yield occurred with very frequent irrigation (10–20% SWD) which also had the greatest irrigation input, while WPI was highest with least frequent irrigation (70% SWD), and WPET was highest with irrigation at 40–50% SWD. This was the case with and without mulch. On the clay loam, the trade-offs were not so pronounced, as maximum yield was reached with irrigation at 50% SWD, with and without mulch. However, both WPET and WPI were maximum and irrigation input least at the lowest irrigation frequency (70% SWD). On both soils, maximum yield, WPET and WPI were higher with mulch, while irrigation input was slightly lower, but mulch had very little effect on the irrigation thresholds at which each parameter was maximised.

Role of Direct Sown Rice Technology for Conservation of Water Resources in Punjab-A Case Study of Amritsar District

India has the largest area under rice crop (about 45 million ha.) and it occupies 23.3 per cent of gross cropped area of the country. The intensive use of water in traditional transplanted rice (TTR) cultivation in northwest Indo Gangetic plains is depleting aquifers. Paddy crop contributes a lot in the agricultural economy of the Punjab state but it was observed in the study that 79.41 per cent of irrigation water being contributed to the production of rice in Amritsar district. As a result of over exploitation of ground water the water table was declined and the ground water development reached to 152 per cent in the district. The use of ground water in the months of May and June was highly important for ground water resource management in the district and it was observed that less than 60 mm rain during the months of May and June contributed negative impact on the ground water situation in the district. It was realized in the study that DSR is a viable alternative to TTR and helpful to overcome the problem of water shortage and labour over TTR as it saves 52.41 (before July) and 21.22 (overall) per cent of irrigations applied. Therefore with the support of the govt, cooperatives and farmers participation; DSR can become a successful alternative to the TTR for optimum use of water resources of Punjab.