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Soil inorganic carbon (SIC) is important carbon reservoirs in desert ecosystems. However, little attention was paid to estimate carbon stock in these regions. In the present study, the distribution of SIC stock was investigated using digital soil mapping in Bikaner district, Rajasthan, India. A total of 187 soil profiles were used for SIC estimation by Quantile regression forest model. Landsat data, terrain attributes and bioclimatic variables were used as environmental variables. Ten-fold cross-validation was used to evaluate model. Equal-area quadratic splines were fitted to soil profile datasets to estimate SIC at six standard soil depths (0–5, 5–15, 15–30, 30–60, 60–100 and 100–200 cm). The SIC in the study area ranged from 0.27 to 27.85 g kg−1 in 0–5 cm and 0.31 to 27.84 g kg−1 in 5–15 cm, respectively. The model could capture reasonable variability (R2 = 11–21%) while predicting SIC for different depths. The Lin's concordance correlation coefficient values ranged from 0.20 to 0.32, indicating poor relationship between the predicted and observed values. The values of prediction interval coverage probability (PICP) recorded 86.4–91.1% for SIC at different depths. Annual precipitation and precipitation seasonality were the most important covariates in soil below the 30 cm depth. The predicted SIC stocks were 10.3 ± 0.01, 81.6 ± 0.07 and 186.7 ± 0.13 Mg ha−1 at 0–15, 0–100 and 0–200 cm, depth, respectively. The uncertainty analysis suggests that there is room to improve the current spatial predictions of SIC. It is anticipated that this digital mapping of SIC will be useful for assessment of carbon cycle in arid regions. [ABSTRACT FROM AUTHOR]

Various faulty farming practices and low-performance cultivars selection are reducing crop yields, factor productivity, and soil fertility. Therefore, there is an urgent need to achieve better nutrient dynamics and sustainable production by selecting more nutrient-responsive cultivars using efficient nutrient management. The present experiment aimed to enhance crop productivity, seed quality, nutrient efficiency, and soil nutrient dynamics through efficient nutrient management under different lentil cultivars. The experiment was laid out in a split-plot design, assigning three cultivars (viz. Sapna, Garima, and HM-1) in the main plots and ten nutrient management practices in the sub-plots, replicating them thrice. Results revealed that cultivar HM-1 recorded significantly higher seed yield (1.59–1.61 Mg ha-1) and the uptake of N (67.2–67.6 kg ha-1), P (6.8–7.0 kg ha-1), K (13.8–13.9 kg ha-1), Zn (60.4–61.1 g ha-1), and Fe (162.5–165.2 g ha-1) in seed compared to Sapna and Garima. Also, the cultivar HM-1 was more efficient in terms of partial factor productivity for NPK (PFP; 24.27–24.59 kg kg-1), partial nutrient balance (PNB; 2.09–2.13 kg kg-1) and internal utilisation efficiency (IUE; 11.64–11.85 kg kg-1). The study showed that the lentil cultivar HM-1 could be successfully grown by substituting 50% RDN with organic manures, i.e., vermicompost, without compromising crop productivity and soil fertility, thereby sustaining soil-human-environment health. [ABSTRACT FROM AUTHOR]

Dill seeds (Anethumgraveolens L.) is the most valuable medicinal seed spice crop of Apiaceae. It bears small yellow flowers in the form of umbels. Being a cross-pollinated crop, floral visitors play vital role in pollination and seed sets. Hence, the present study was conducted at the ICAR-National Research Centre on Seed Spices, Ajmer (Rajasthan), India to discover the pollinator's community, foraging behaviour and abundance of most frequent pollinators and different modes of pollination on seed yield and quality of this seed spice crop. The insect visitors community of dill seeds was composed of 28 insect species belonging to 14 families of 6 orders. Most of floral visitors started their foraging activity at 8.00 h, reached peak activity between 12.00 and 14.00 h and their activity ceased at 18.00 h. Apisflorea,A.dorsata,A.mellifera, solitary bee, Halictus sp. and two unidentified species of Hymenoptera; Episyrphusbalteatus (DeGeer), Episyrphus sp., Eristalis sp and two other Musca species of Diptera were identified as potential and regular floral visitors of dill seeds. The highest seed yield of 1505.63 kg/ha was recorded in the treated plots provided with only 10% jaggery solution and was at par with the open pollination. A lower seed yield of 1432.5 kg/ha was recorded in plots pollinated only with A.mellifera inside insect cages. Open pollination with 10% jaggery solution spray increased the seed yield of dill seed crop by 57%, one-thousand seed test weight by 96% and the essential oil content by 27% over control plots. These results show that managed pollination is a much better way to enhance yields and quality of dill seed crop than other treatments including only honeybee-based pollination. [ABSTRACT FROM AUTHOR]

The degradation of agricultural land, both chemical and biological, is a big concern all over the world. Crop cultivation practices that are distinctive to each location have negative consequences for agricultural production. Therefore, there is an urgent need for better crop and soil management techniques. This experiment was conducted for 5 years (2016–2020) to identify the best crop establishment‐cum‐residue management (CERM) practices and suitable crops for succession after the rice harvest in rice‐fallow ecosystems of India. Experimentation was conducted in the split‐plot design and each treatment was replicated thrice, having CERM in main‐plot and post‐rainy season/winter crops in sub‐plot. All the CERM treatments had two variants, with crop residue (R+) and without crop residue (R−). Rice yields were markedly higher (19.1%–32.2%) in transplanted puddled rice with residue (TPR‐R+) over conventional‐till direct seeded rice (CTDSR) and zero‐till DSR (ZTDSR) treatments. However, TPR adversely impacted the performance of all the post‐rainy pulses/oilseed crops. Post‐rainy season crop yields under ZTDSR/CTDSR were 14.9%–45.8% higher leading to higher system productivity as compared to TPR. ZTDSR with residue retention showed higher soil aggregation. The practice of ZTDSR increased the soil dehydrogenase activity (46.2%), urease activity (29.8%), soil microbial biomass carbon (65.4), and fluorescein diacetate activity (9.0%) in the crop root zone with 3.3‐ and 4.47‐times higher earthworm population and earthworm biomass, respectively. The rice‐pulse system showed 1.74‐times more earthworm population over rice‐oilseed sequences. Total soil organic carbon (SOC) stock in ZTDSR was 21.8% higher over TPR in 0–45 cm soil profile. Thus, the adoption of ZTDSR practices and diversification of rice‐fallows with pulses crops is recommended for enhancing the crop productivity, increasing SOC stock, and improving soil biological properties in the rice‐fallow ecosystems of India. [ABSTRACT FROM AUTHOR]

In Paris Climate Agreement (COP 21) in December 2015, India committed to cut its carbon (C) emissions by 30–35% of its GDP (gross domestic product) and attain 40% of installed energy from renewables by 2030. In the Glasgow Climate Pact (COP 26), an agreement developed at COP26 of UNFCCC in November 2021, India committed to enhancing its renewable energy (RE) capacity to 500 GW and installing 50% of its power from renewable resources by 2030. It is projected that this will help India to reduce its C emissions by 1Bt, reduce emission intensity to the economy by 45% by 2030, and meet the goal of C neutral economy by 2070. Realization of these highly ambitious commitments made at COP26 can be determined by the nation's growth in REs after COP21. Therefore, this article reviews the overall development of renewable energies – solar, wind, biomass, hydrogen, and hydro – in India after COP21 by the end of December 2021. This review provides detailed information on various policies and roadmaps for each energy sector commitments. It identifies major technical and social challenges associated with the sustainability of these sectors. This review offers insights into how realistically ambitious plans India has for 'phasing down' the use of coal by 2050 and being a carbon-neutral economy by 2070. India achieved massive success through solar energy after COP21 and 80% of future investments are for solar energy. Comparatively, there has been the least investment in other REs such as bioenergy, water, and wind. • Review of renewable energy research, policies, and developments in India after COP21. • Maximum achievements of goals are based on the installed capacity of solar energy. • US$ 38–40 billion investment supports solar energy generation, storage, and distribution. • US$ 500 billion is needed for capacity building to achieve 450 GW by 2030. • Renewable energies from biomass, water, and wind are in their infancy. [ABSTRACT FROM AUTHOR]

A field experiment was conducted to study the effects of tillage and mulch on weed growth, soil moisture storage, productivity and profitability of upland rice during 2012-2013 at Lembucherra, India. Tillage treatments included CT-RI: conventional tillage with 100% residue incorporation and NT-RR: no-till with 100% residue retention. Mulches included rice straw (SM), Gliricidia (GM), brown manuring (BM) and none (NM). CT-RI registered the highest total weed density (89-168 weeds m−2) and biomass (9.6-183 g dry weight m−2) than those for the NT-RR (75-161 weed m−2 and 8-155 g dry weight m−2). In addition, NT-RR stored (122-172 mm) more soil moisture (0-40 cm soil depth) in comparison with that for the CT-RI treatment (110-161 mm) during crop growing season. Tillage treatments did not have the significant effect on yields. NT-RR reduced the cost of cultivation by 31.5% compared with that for the CT-RI. Thus, the net returns under NT-RR were more than those for the CT-RI. The BM recorded the lowest weed biomass and density as compared to that under other mulches. Therefore, cultivation of upland rice using NT along with BM mulching enhanced productivity and profitability of rice cultivation in India. [ABSTRACT FROM AUTHOR]

Groundwater and soil potassium deficiencies are present in northern India. Sugarcane is a vital crop in the Indian Punjab; it is grown on approximately 91,000 hectares with an average yield of 80 tonnes ha−1 and a sugar recovery rate of 9.59%. The role of potassium (K) fertilizer under both sufficient and deficient irrigation in ratoon sugarcane crops is not well documented. We conducted a split-plot ratoon cane experiment during 2020–2021 at the Gurdaspur Regional Research Station of Punjab Agricultural University, India, on K-deficient soils. Main treatments were fully irrigated (I1) and water stressed (I0) conditions, with sub-treatments reflecting K fertilizer application rates of 0 (M1), 67 (M2), 133 (M3), and 200 (M4) kg K ha−1. The ratoon sugarcane performance was assessed in terms of growth, productivity, sugar quality and incidence of key insect pests. At harvest, trends in the growth and yield parameters in I1 were improved over the I0 treatment, with cane height (+12.2%), diameter (+3.3%), number of internodes (+5.4%), biomass yield (+7.6%) and cane yield (+5.9%) all higher, although little significant difference was observed between treatments. Ratoon cane yield under irrigation was 57.1 tonnes ha−1; in water-stressed conditions, it was 54.7 tonnes ha−1. In terms of sugarcane quality parameters, measured 12 months after harvesting the initial seed crop, values of Brix (+3.6%), pol (+3.9%), commercial cane sugar percentage (+4.0%) and extractable sugar percentage (+2.8%) were all higher in the irrigated treatments than the water-stressed plot. Irrigated treatments also had a significantly lower incidence of two key insect pests: top borer (Scirpophaga excerptalis) was reduced by 18.5% and stalk borer (Chilo auricilius) by 21.7%. The M3 and M4 treatments resulted in the highest cane yield and lowest incidence of insect pests compared to other K-fertilizer treatments. Economic return on K-fertilizer application increased with increasing fertilizer dosage. Under the potassium-deficient water-stressed conditions of the region of north India, a fertilizer application rate of 133 kg K ha−1 is recommended to improve ratoon sugarcane growth, yield, and quality parameters and economic returns for sugarcane farmers. [ABSTRACT FROM AUTHOR]

• The rice (Oryza sativa)–rice system (RRS) is principal production system in Asia. • Loss of soil carbon and nitrogen pools is declining the productivity of RRS. • Intensive tillage and improper nutrient management are reasons of the loss of soil C and N. • RT/NT with INM and residue recycling can sequestrate C and N in paddy soils. • Cultivation RRS under CA with INM/IPNM and residue recycling could enhance productivity. The rice (Oryza sativa)–rice system (RRS) is the most important agricultural production system, and it provides staple food, income, employment, and livelihoods to millions of farmers in the Indian sub- continent, especially in the eastern and north eastern region (NER) of India. However, soil degradation, due to loss of soil carbon (C) and nitrogen (N) pools, is declining the productivity of RRS and threatening the region's food security. Intensive tillage along with improper residues and nutrient management practices are among the reasons of the loss of soil C and N pools and decline in rice productivity. Therefore, a 3-year (2013-15) field study was conducted to evaluate the effects of tillage, residues and nutrient management practices on productivity, soil C and N sequestration in RRS at the Indian Council of Agricultural Research (ICAR)-Research Complex for the North Eastern Hill (NEH) Region, Lembucherra (52 m, above sea level), Tripura, India. The experiment consisted of five combinations of tillage [conventional tillage (CT), reduced tillage (RT) and no-till (NT)], residue [30% rice residue incorporation (RI) and/or residue retention (RR)] and nutrient management practices [inorganic, organic (FYM-farmyard manure, GLM-green leaf manuring) and biofertilizers] in wet (WR) and dry season rice (DR). Results revealed that RT along with improved plant nutrient management (IPNM) comprising 25% N (20 kg N) through GLM + 60 kg N, 9 kg phosphorus (P), 17 kg potassium (K), 2 kg Boron (B) and 5 kg zinc (Zn) ha−1 through fertilizer + cellulose decomposition microorganism and RR in WR produced significantly higher grain yield (5.15 Mg ha−1) as compared to other treatments. However, the DR transplanted under CT + integrated nutrient management (INM) comprising 25% N through FYM and 75% N and remaining P and K (after deducting quantity supplied by FYM) through inorganic fertilizer + RI produced more grain (5.1–5.3 Mg ha−1), straw (7.0–7.2 Mg ha−1), root (1.3–1.4 Mg ha−1) and total biomass (13.4–13.9 Mg ha−1) yield than that of the farmers' practice (FP) and other treatment combinations, across the years. The highest system productivity of RRS was recorded under T 3 (RT + IPNM + RR in WR and CT + INM + RI in DR). Therefore, the highest biomass, C, and N were also recycled in the system through the same treatment combinations. Soil under T 3 had a lower bulk density (ρ b), the highest soil organic carbon (SOC)/N concentration, pool, accumulation, sequestration, C retention efficiency, soil microbial biomass C and dehydrogenase activities than other treatments. A total amount of 1.30 Mg C ha−1 was accumulated under soils of T 3 with the rate of SOC sequestration of 427.9 kg ha−1 yr−1 under RRS. Thus, adopting RRS under RT/NT with INM/IPNM and effective residue recycling is recommended for enhancing the system productivity, C and N sequestration in paddy soils of the NER of India. [ABSTRACT FROM AUTHOR]

Carbon (C) is a key product of forests, but not widely studied for available C stock, and biomass of tree species in typical forest ecosystems of India. Therefore, it is useful to estimate C stock at national and regional levels for establishing forest-based policies and developing roadmap for long-term plans and strategies to reduce the rate of increase of atmospheric carbon dioxide (CO 2). Hence, present investigation was conducted to assess C storage and CO 2 fluxes in tropical dry deciduous forest ecosystems of Jhumpa and Kairu in the southern Haryana, India. The C stock of trees in above ground biomass (AGB) was calculated by assuming the C content at 50% of the total biomass. Concentration of C in composite samples of shoots and roots of shrubs and herbs was estimated by the ash method. Soil C storage was determined on the basis of C concentration and soil bulk density up to 60 cm depth. The AGB of trees ranged from 33.1 to 75.8 Mg ha−1; the belowground biomass from 9.0 to 18.5 Mg ha−1 and total plant C storage from 24.3 to 53.9 Mg C ha−1. The total biomass of shrubs was 16.2 Mg ha−1 for the Salvadora oleoides forest at Jhumpa compared with 8.4 Mg ha−1 for the Acacia senegal-Acacia tortilis forest at Kairu. Net primary productivity of various components of trees in these forest ecosystems ranged from 8.1 to 9.6 Mg ha−1 y−1 and net flux of C from 4.6 to 5.8 Mg C ha−1 y−1. The annual litter fall in two forest ecosystems ranged from 3356 to 4498 Kg ha−1. S. oleoides contributed 50.0% and 47.3% towards the above ground and below ground C pools corresponding to the 17.9 Mg C ha−1and 4.1 Mg C ha−1, respectively. S. oleoides played a dominant role in biomass production and C assimilation in S. oleoides-A. tortilis forest at Jhumpa, while Prosopis juliflora and A. senegal were the highest contributors in A. senegal-A. tortilis forest at Kairu because of a high girth class and high density of trees, respectively. The cumulative soil organic carbon (SOC) stock up to 60 cm depth was more in A. senegal-A. tortilis forest at Kairu (16.3 Mg C ha−1) than that in the SO-AT forest at Jhumpa (12.9 Mg C ha−1). The results of this study revealed that S. oleoides and P. juliflora are key species as they sequester more C under a range of disturbances. Carbon sequestration potential of the studied forest ecosystems was 3.55 to 4.35 Mg C ha−1 y−1 which indicates a high C sequestration potential of these ecosystems. • We assessed C sequestration potential in tropical dry deciduous forest ecosystems. • Net primary productivity of trees ranged from 8.1 to 9.6 Mg ha−1 yr−1. • Trees sequester significant amount of carbon both in the soil and the plant biomass. • Forests in arid regions provide valuable ecosystem services. [ABSTRACT FROM AUTHOR]

Identification of the appropriate tillage production system having lower energy use and carbon-emission, and better crop productivity is becoming increasingly important to maintain the environmental sustainability. In the present study, a comprehensive system analysis was performed for four consecutive years (2016–2019) in three major agroecosystems of eastern India: eastern Indo-Gangetic plain, coastal agroecosystem and hill & plateau region. Six rice-based production systems with different levels of farm mechanization viz. , a) fully mechanized tillage, b) partly mechanized tillage and c) traditional tillage were considered in the analysis. The main aim was to assess the energy flow and carbon-balance of diverse tillage production systems. Among the different sources of total input energy, chemical fertilizer accounted for the highest energy used in partly mechanized tillage (44%) and mechanized tillage (38%) followed by diesel, irrigation water, plant protection chemical, seed and electricity. Seed, human, animal energy and farmyard manure accounted for 21, 20, 16 and 16%, respectively, of the total energy input in traditional tillage. Maximum energy input (52161 MJ ha−1) was noted in mechanized tillage and minimum with traditional tillage (16879 MJ ha−1). Cropping systems followed in eastern Indo-Gangetic plain were more energy-intensive (50908 MJ ha−1) compared to coastal-ecosystem (27459 MJ ha−1). On an average, the total energy output in mechanized tillage (395245 MJ ha−1) were 0.3 and 2.4 times higher over partly mechanized and traditional tillage, respectively. Overall, the present results indicated that partly mechanized tillage and coastal agroecosystem were the most energy-efficient with an energy ratio of 8.88 and 9.81, respectively. Mechanized tillage was 0.24 and 1.66 times more carbon-intensive in comparison to partly mechanized and traditional tillage system. Mechanized tillage had higher carbon efficiency (3.75), carbon-sustainability index (2.75), carbon-footprint in spatial scales (4342 kg CO 2 eq. ha−1), but had 34% less carbon-footprint in yield scales compared to traditional tillage. Mechanized tillage showed 22 and 73% higher system productivity compared to partly mechanized and traditional tillage, respectively. Partly mechanized tillage had a 23% lower cultivation cost than mechanized tillage. Thus, the present study suggests that partly mechanize tillage was the most appropriate energy and carbon-efficient production system in eastern India. [Display omitted] • Energy and carbon budgets of diverse tillage systems in eastern India was analysed. • Partly mechanized tillage and coastal agroecosystems were the most energy-efficient. • Mechanized production system was 24 and 56% more energy-intensive than others. • Human energy profitability was increased by 5.48 times in mechanized tillage system. • Mechanized tillage had 0.23–1.61 times more carbon footprint in spatial scale. [ABSTRACT FROM AUTHOR]

There is an urgent need for identification of the eco-friendly/cleaner production system that is more productive and profitable; efficient user of energy, water, and carbon-based inputs, and also environmentally safer. The four years study was conducted from 2016 to 2019, where the dominant rice-wheat cropping system is practiced extensively after 'Green Revolution'. The objectives of the experiment were to evaluate: (1) energy budgeting, (2) carbon auditing, (3) production and economic efficiency of diverse cropping systems for upland rainfed as well as irrigated ecosystems of eastern India. Tillage and cropping system treatments were laid out according to a completely randomized block design and replicated thrice. Ten cropping sequences were comprised of: T1) a farmers' practice of transplanted rice-wheat-mungbean, T2) conventional till-direct seeded rice (CTDSR)-wheat-mungbean, T3) soybean-maize, T4) CTDSR-mustard-urdbean, T5) foxtail millet-lentil-fallow, T6) pearl millet-chickpea-fallow, T7) finger millet- toria -fallow, T8) sorghum (grain)-chickpea-fallow, T9) maize cob–pigeon pea, and T10) sorghum (fodder)-mustard-urdbean. Energy contributions of different inputs were 42–55, 12–21, 8–18, and 4–12% for fertilizers, diesel, labour, and electricity, respectively. The amount of indirect (fertilizer, chemicals, and machinery) and direct (diesel and electricity) non-renewable energy inputs were 40–60 and 18–26%, respectively. Indirect renewable energy input (seed and crop residues) was 1–7% as compared to 15–24% of direct-renewable energy (human labour and irrigation water). The maximum energy input was recorded for T1 (53511 MJ ha−1). The maximum biomass production (40.2 Mg ha−1) was recorded with T9, while the maximum benefit: cost ratio (3.64) was noted for T10 and T8. The highest specific energy (33.5 MJ kg−1) and energy productivity (0.92 kg MJ−1) were recorded in T8 treatment. Irrespective of cropping systems, retention of crop residues accounted for 28.6–58.5% of total carbon input. The carbon sustainability index was 5–7 times higher for the millet-based production system [T6 (9.32) and T8 (10.27)] compared to cereal-based systems [T1 (1.66) and T2 (1.21)]. Diversification of the rice-wheat system through climate-resilient millets-based production system reduced 84% energy consumption and 87% carbon footprint. The millet-based production system also helps in reducing the carbon input by 172% and improves the energy use efficiency by 61% compared to the cereal-based cropping system. Therefore, the study has an innovative idea to support the crop modelling, policymakers, government planners, researchers, and producers to achieve the sustainable development goals in Indo-Gangetic Plains and similar agro-climatic conditions of South Asia. Image 1 • Carbon-cum-energy efficient production system for the diverse agro-ecosystem of South Asia. • The millet-based system reduced 84% energy use & 87% carbon-footprint than the rice-wheat system. • Energy ratio in millet-based system increase 61% output and reduction 172% carbon -input. • The millet-based had 56 & 58% more nutrient & non-renewable energy efficiency. • The millet-based emerged as a viable alternative to the rice-wheat system. [ABSTRACT FROM AUTHOR]

Groundwater resources are alarmingly depleting due to over-exploitation and significant climate changes over time. Therefore, demarcation of groundwater potential zones is essential for addressing the needs of various industries in semi-arid area. Depleting groundwater resources, topography, aquifer features and climatic factors make it necessary to demarcate ground water potential zones in semiarid region of Rajasthan. The Analytical Hierarchy Process (AHP), Geographic Information System (GIS), and Multi Influence Factor (MIF) were used to determine the groundwater potential zones (GWPZs) in the semi-arid region of Jaipur, located in western Rajasthan. In present study, ten influential factors were employed i.e., geomorphology, land use/land cover (LULC), drainage density, rainfall, topographic wetness index (TWI), soil texture, slope, roughness, topographic position index (TPI) and curvature. In AHP technique, the pairwise comparison matrix was generated, and weightages were given to each thematic layer while for MIF, a proposed score for each layer was computed from the aggregate weight of major and minor effects. The GWPZ map generated by AHP technique was categorised into three parts: high, moderate and poor potential zones, covering 13%, 50.7% and 36.3% of the district. While, the GWPZ map produced with the MIF technique was also divided into the same poor, moderate, and high categories, encompassing 35.3, 44.1, and 20.6% of the district, respectively. The results of AHP and MIF techniques were then cross-validated with well depth data obtained from CGWB report, 2019-20. The receiver operating characteristics (ROC) were plotted and the findings shows that the Area under the Curve (AUC) was 79% and 76% for AHP and MIF, respectively which is considered as moderate to high in predictive precision. The study would be helpful in locating drilling sites for groundwater exploration and developing sustainable groundwater and land use policies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)