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Not AvailableSalt-induced soil degradation is a serious threat to global agriculture which is responsible for diminished productivity of agro-ecosystems. Irrigation with poor quality water and indiscriminate use of chemical fertilizers to increase crop productivity creates salt accumulation in soil profile thereby reducing crop sustainability. High concentration of salts in soil inhibits plant growth due to low osmotic potential of the soil solution, ion toxicity and imbalance reduces nutrient uptake, crop yields. Low productivity of saline soils is not only due to salt toxicity or excess amounts of soluble salts but also lack of available mineral nutrients especially nitrogen, phosphorus, potassium and soil organic matter. Hence, sustainable management of salt-affected soils are paramount importance to meet the demands of food grain production for an ever-rising population in the world. Recently, municipal solid waste has gained importance as an organic amendment for restoring soil fertility and finally contributing to productivity of salt-affected soils. This paper compares extant waste generation, their properties and standards pertinent to municipal solid waste in different countries and explores the unique recent history in some countries that shows high environmental regard and rapid changes and also suggests policy experiencing from high environmental regard and rapid changes from other countries, so that policy makers can propose new or revise current municipal solid waste standards for salt affected soils. Municipal solid waste compost improves soil biological, physical and chemical properties because of high soil organic matter and lower concentration of pollutants. Therefore, the use of municipal solid waste in salt-affected soils could be an alternative to costly chemical amendments as well as reduce the reliance on chemical fertilizers for increasing productivity of salt-affected soil. The municipal solid wastes significantly improve crop yields. However, further long-term experimental investigations are needed to re-validate the application of municipal solid waste compost in improving physical, chemical and biological properties and to step up organic fertilization use in a wide range of both saline and sodic soils. In future, research should be directed to address these issues globally to minimise ecological disturbances and to set environmental standards, and evaluate the feasibility of the policies in different countries and their impact on socio-economic conditions of local people.Not Availabl

Quantitative mapping of soil salinity using the DUALEM-21S instrument and EM inversion software

To generate baseline data for the purpose of monitoring the efficacy of remediation of a degraded landscape, we demonstrate a method for 3-dimensional mapping of electrical conductivity of saturated soil paste extract (ECe) across a study field in central Haryana, India. This is achieved by establishing a linear relationship between calculated true electrical conductivity (σ) and laboratory measured ECe at various depths (0–0.3, 0.3–0.6, 0.6–0.9, and 0.9–1.2 m). We estimate σ by inverting DUALEM-21S apparent electrical conductivity (ECa) data using a quasi-3-dimensional inversion algorithm (EM4Soil-V302). The best linear relationship (ECe = −11.814 + 0.043 × σ) was achieved using full solution (FS), S1 inversion algorithm, and a damping factor (λ) of 0.6 that had a large coefficient of determination (R2 = 0.84). A cross-validation technique was used to validate the model, and given the high accuracy (RMSE = 8.31 dS m−1), small bias (mean error = −0.0628 dS m−1), large R2 = 0.82, and Lin's concordance (0.93), between measured and predicted ECe, we were well able to predict the ECe distribution at all the four depths. However, the predictions made in the topsoil (0–0.3 m) at a few locations were poor due to limited data availability in areas where ECa changed rapidly. In this regard, improvements in prediction can be achieved by collection of ECa in more closely spaced transects, particularly in areas where ECa varies over short spatial scales. Also, equivalent results can be achieved using smaller combinations of ECa data (i.e., DAULEM-1S, DUALEM-2S), although with some loss in precision, bias, and concordance

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Not AvailableWater and labour scarcity besides increasing cost of cultivation in transplanted puddle rice (TPR) warrants to develop and adopt input use efficient and cost effective direct seeded rice (DSR) method of cultivation. Though DSR saves substantial amount of irrigation but there are contradictory observations on yield realization. Therefore, a two year field study was undertaken with the aim to develop efficient irrigation strategy for maximizing tilled DSR yield with minimum irrigation input. Total 08 irrigation strategies, based on 03 soil matric potential (SMP) levels (−15, −30 and −45 kPa) and their combinations based on crop growth stages, were evaluated for fine grain aromatic (Basmati) rice variety ‘CSR30’. Responses of respective irrigation strategies were evaluated on crop water use and its components, biometric parameters and yield attributes and yield of DSR. Performance of DSR was also compared with standard TPR practice. Soil profile moisture content ranged from 32 to 39, 27–39 and 22–39% in−15,−30 and−45 kPa irrigation regimes, respectively. Irrigation input in DSR method of cultivation varied between 709–1541mm as compared to 1807mm of TPR. With different irrigation strategies, DSR grain yield and irrigation water productivity (IWP) varied from 1.72 to 2.89 Mg/ha and 0.19–0.24 kg/m3, respectively. Irrigation threshold −15 kPa at all stages in DSR produced the highest yield and crop water productivity (CWP; 0.48 kg/m3), but with lowest IWP. Irrigations at or below −30 kPa during initial phase (< 90 DAS) and at−15 kPa during remaining period produced comparable yield with significantly higher IWP. Though TPR registered lower IWP (0.18 kg/m3) as compared to the best DSR treatment but recorded about 11% higher grain yield with significantly higher crop water productivity (0.58 kg/m3) than DSR. Water balance studies revealed better utilization of precipitation in DSR due to irrigations at more negative SMP. Overall, study suggests irrigation scheduling at <−30 kPa during initial phase and−15 kPa during the remaining crop season proved to be the optimum irrigation threshold for maximizing DSR yield with limited irrigation input.Not Availabl

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Not AvailableSalinity affects phosphorus (P) fractionation and its availability in soil and thereby crop growth as well as yields. Therefore understanding of P transformation and availability in soil with use of different sources of P is crucial to adopt appropriate P management practices for improving productivity of saline soils. A field experiment comprising of four treatments replicated thrice was conducted for three consecutive years during 2012–15. Treatments consisted of control (Ct), recommended dose of N-P-K fertilizers at 60-30-30 kg ha−1 (RDF-100%), municipal solid waste compost at 16 Mg ha−1 (MSWC-16) and MSWC at 8 Mg ha−1 +RDF-50% (MSWC- 8 +RDF-50%) laid out in randomized complete block design. Among different phosphorous fractions across the years; saloid-P (S-P), iron-P (Fe-P), calcium-P (Ca-P) and occluded-P (Occ-P) increased markedly after 2012–13 with continuous increase in subsequent years in all treatments compared to Ct. However, MSWC-8 +RDF-50% produced significant increase in all P fractions, including Olsen-P, total-P (Pt) and inorganic-P (Pi), except S-P as compared to RDF-100%. Whereas, all P fractions progressively declined in Ct from 2012–13 to 2015, indicating continuous removal by mustard (Brassica juncea) and pearl millet (Pennisetumglaucum). MSWC-8 +RDF-50% also recorded 16 and 22% higher organic-P (Po) and alkaline phosphatase activity (ALPA), respectively during 2015 over 2012–13 in corresponding treatment. Soil organic carbon (SOC) increased with RDF-100% over Ct across the years as well as within year; however, the highest SOC (5.7 g kg−1) was observed with MSWC- 8 +RDF-50%. Mean soil salinity (electrical conductivity; EC) decreased by 38 and 25% with MSWC-8 +RDF- 50% and MSWC-16, respectively relative to Ct (4.8 dSm−1). Relatively better P availability and lower soil EC with MSWC-8 +RDF-50% and resulted significantly higher mean (of three year) grain yield of mustard (2.38 Mg ha−1) and pearl millet (2.44 Mg ha−1) over RDF-100%. Nevertheless, RDF-100% produced 11 and 15% higher mean grain yield of mustard and pearl millet, respectively than Ct. MSWC-8 +RDF-50% also resulted in higher P uptake by grain of both crops as compared to RDF-100%. Our results highlighted that integrated use of organic amendment (MSWC-8) and mineral fertilizers (RDF-50%) is beneficial option for improving P availability and crop yields under saline conditions.Not Availabl

Effects of municipal solid waste compost, rice-straw compost and mineral fertilisers on biological and chemical properties of a saline soil and yields in a mustard–pearl millet cropping system

We investigated the effects of organic amendments, municipal solid waste compost (MSWC) and rice-straw compost (RSC) with and without mineral fertilisers on biological and chemical properties of a saline soil. Field experiments were conducted for two consecutive years during 2012–14. In the first year, application of 8tha–1 of MSWC+50% of the recommended dose of fertilisers (RDF) resulted in higher microbial biomass carbon (MBC), enzyme activities, soil organic carbon (SOC), available nitrogen (N), phosphorus (P) and potassium (K) than 7tha–1 of RSC+50% RDF, after mustard (Brassica juncea) and pearl millet (Pennisetum glaucum) harvests. Combined use of 8tha–1 of MSWC+50% RDF resulted in 47% and 54% more MBC than the unfertilised control after mustard and pearl millet harvests, respectively. Dehydrogenase activity was significantly higher with 100% RDF than the control after 2 years of the cropping cycle. Among organic amendments, MSWC was superior to RSC in terms of MBC, and activities of dehydrogenase, alkaline phosphatase and urease. SOC was significantly increased under MSWC+50% RDF compared with 100% RDF alone. Significant build-up of soil fertility in terms of available N, P and K was observed with RSC+50% RDF compared with the control. During the second year of the cropping system, soil treated with RSC+50% RDF had 14%, 17% and 9% higher N, P and K than soil treated with 100% RDF, after pearl millet harvest. The magnitude of change in soil electrical conductivity and pH was low during 2012–13; however, soil salinity decreased by 55% and 48% with MSWC+50% RDF and RSC+50% RDF, respectively, relative to the control at 120 days of pearl millet growth in 2013–14. Application of MSWC +50% RDF produced 2.5 and 2.70tha–1 of mustard and pearl millet, and increased grain yield by 19% and 15%, respectively, compared with 100% RDF. Integrated use organic amendments and mineral fertiliser is recommended for promoting biological and chemical properties of saline soil in a mustard–pearl millet cropping system.</jats:p

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Not AvailableSalt-induced soil degradation is a serious threat to global agriculture which is responsible for diminished productivity of agro-ecosystems. Irrigation with poor quality water and indiscriminate use of chemical fertilizers to increase crop productivity creates salt accumulation in soil profile thereby reducing crop sustainability. High concentration of salts in soil inhibits plant growth due to low osmotic potential of the soil solution, ion toxicity and imbalance reduces nutrient uptake, crop yields. Low productivity of saline soils is not only due to salt toxicity or excess amounts of soluble salts but also lack of available mineral nutrients especially nitrogen, phosphorus, potassium and soil organic matter. Hence, sustainable management of salt-affected soils are paramount importance to meet the demands of food grain production for an ever-rising population in the world. Recently, municipal solid waste has gained importance as an organic amendment for restoring soil fertility and finally contributing to productivity of salt-affected soils. This paper compares extant waste generation, their properties and standards pertinent to municipal solid waste in different countries and explores the unique recent history in some countries that shows high environmental regard and rapid changes and also suggests policy experiencing from high environmental regard and rapid changes from other countries, so that policy makers can propose new or revise current municipal solid waste standards for salt affected soils. Municipal solid waste compost improves soil biological, physical and chemical properties because of high soil organic matter and lower concentration of pollutants. Therefore, the use of municipal solid waste in salt-affected soils could be an alternative to costly chemical amendments as well as reduce the reliance on chemical fertilizers for increasing productivity of salt-affected soil. The municipal solid wastes significantly improve crop yields. However, further long-term experimental investigations are needed to re-validate the application of municipal solid waste compost in improving physical, chemical and biological properties and to step up organic fertilization use in a wide range of both saline and sodic soils. In future, research should be directed to address these issues globally to minimise ecological disturbances and to set environmental standards, and evaluate the feasibility of the policies in different countries and their impact on socio-economic conditions of local people.Not Availabl

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