Fertilization and Soil Ploughing Practices under Changing Physical Environment Lead to Soil Organic Carbon Dynamics under Conservation Agriculture in Rice-Wheat Cropping System: A Scoping Review

Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the loss of soil-organic-carbon (SOC), which further enhances soil fertility. Different fractions of SOC pools react to the alterations in management practices and indicate changes in SOC dynamics as compared to total C in the soil. Higher SOC levels in soil have been observed in case of reduced/no-till (NT) practices than conventional tillage (CT). However, between CT and zero tillage/NT, total SOC stocks diminished with an increase in soil depth, which demonstrated that the benefits of SOC are more pronounced in the topsoil under NT. Soil aggregation provides physical protection to C associated with different-sized particles, thus, the improvement in soil aggregation through CA is an effective way to mitigate soil C loss. Along with less soil disturbance, residual management, suitable crop rotation, rational application of manures and fertilizers, and integrated nutrient management have been found to be effective in not only improving soil C stock but also enhancing the soil health and productivity. Thus, CA can be considered as a potential method in the build-up of SOC of soil in rice-wheat system.

Evaluation and Comparison of DTPA Extractanting Methods for Available Cationic Micronutrients in Non-acidic Soils of Andhra Pradesh,India

The research work was carried out to compare and evaluate the extractability of cationic micronutrients(Zn,Cu,Fe and Mn)using widely employed diethylene triamine pentaacetic acid(DTPA)-triethanolamine(TEA)-CaCl2 method with that of multinutrient extractant(ammonium bicarbonate(AB)-DTPA)in Inceptisols,Alfisols and Entisols in the erstwhile united Andhra Pradesh.The percent variation of extraction of Zn was higher in soils with DTPA-TEA-CaCl2 over AB-DTPA method in all the soil orders(types)in the range of 35.3% to 46.2%.AB-DTPA extracted high amounts of Cu to an extent of 10%-21% in Entisols and Alfisls,respectively.In Inceptisols both extracatants extracted equal amounts of Cu.AB-DTPA extracted high amounts of Fe 13% and 18% in Alfisols and Entisols compared to that of DTPA-TEA-CaCl2 method and DTPA-TEA-CaCl2 method was good extract for Fe in Inceptisols and even for Mn in Alfisols.The amounts of micronutrient contents extracted were found to be highly and significantly correlated with soil properties like electrical conductivity(EC)and organic carbon(OC).The individual micronutrient contents of Zn,Cu and Fe extracted by DTPA-TEA-CaCl2 methods were found to be highly correlated with that of AB-DTPA extractant.However,such correlation was not observed for Mn extraction when all soils were grouped.

Microbial Solubilization of Phosphorus from Nano Rock Phosphate

Phosphorus （P） is a major growth-limiting nutrient, and unlike the case of nitrogen （N）, there is no large atmospheric source that can be made biologically available. Moreover, P governs crucial role in plant as it stimulates root development and growth, gives plant rapid and vigorous start leading to better tillering and essential for many metabolic processes for seed formation. Soil microbes play very important role in bio-weathering and biodegradation. The microorganisms produce low molecular mass organic acids, which attack the phosphate structure and transform phosphorus from non-utilizable to the utilizable for the plants form. The test of the relative efficiency of isolated strains is carried out by selecting the microorganisms that are capable of producing a halo/clear zone on a plate owing to the production of organic acids into the surrounding medium. It is a well-known fact that as the particle size of rock phosphate decreases, the microbe mediated solubilization of rock phosphate increases in soil. In the present investigation, microbial solubilization of nano rock phosphate （〈 100 nm） particles was studied. Experimental results revealed that Pseudomonas striata solubilized 11.45% of the total P after 24 h of incubation from nano rock phosphate particles while 28.95% and 21.19% of the total P was solubilized by Aspergillus niger （black pigmented） and Aspergillus niger （green pigmented）, respectively. It was also observed that Aspergillus niger has the higher ability to dissolve Udaipur rock phosphate than Pseudomonas striata.

Bio-Fortification of Oats Fodder through Zinc Enrichment to Reduce Animal Malnutrition

The availability of poor quality fodders for livestock feeding is a major hurdle for the dairy industry in South Asia. Thelow content of Zn in fodders, leads to its malnutrition in animals. In fodders, Zn facilitates protein synthesis, gene expressions,energy production and involves in various metabolic activities of plants, animals and humans. To achieve these objectives,multi-location field trials were conducted on enrichment of oats fodder with Zn through bio-fortification. The experiment consists ofeight different treatment combinations for enrichment of oats fodder with Zn including control, soil and soil plus foliar application ofZn at different stages of plant growth. The results of the study reported that soil application of Zn at the rate of 25 kg/ha and soil +foliar application of Zn at 0.5% at 60 days after sowing (DAS) (jointing stage), 90 DAS (booting stage) and both 60 DAS and 90DAS showed improvement in plant growth parameters. The results further reported that foliar application of Zn at the rate of 0.5% at60 DAS, 90 DAS, both 60 DAS and 90 DAS reported significant increase in biomass yield and fodder quality. Integrated applicationof Zn at 25 kg/ha in soil along with foliar Zn at the rate of 0.5% at 60 DAS and 90 DAS showed maximum Zn enrichment, greenfodder yield, dry fodder yield, plant height, and Zn accumulation in oats fodder as compared to other treatments of Zn application.These treatments of Zn application through integrated mode also reported significant improvement in fodder quality with maximumcrude protein (CP) and crude protein yield (CPY) while neutral detergent fiber (NDF), acid detergent fiber (ADF), ash content andorganic matter showed a non-significant effect. Thus, the results of experimental study concluded that soil and foliar application ofZn at 25 kg/ha and 0.5% Zn, respectively, at 60 DAS and 90 DAS enhanced the growth, yield and quality of oats fodder which willcertainly improve livestock production through bio-fortification.

Soil Test Based Fertilizer Prescriptions through Inductive cum Targeted Yield Model for Sesamum on Alfisol

Studies on Soil Test Crop Response Based Integrated Plant Nutrition System(STCR-IPNS)were conducted for three years adopting the Inductive cum Targeted Yield Model,on alfisols of Unified Andhra Pradesh,Southern India during summer 2016-2018 in order to develop fertilizer prescriptions through IPNS for the desired yield targets of Sesamum under field conditions.The bases for making the fertilizer prescriptions viz.nutrient requirement(NR),contribution of nutrients from soil(Cs),fertilizer(Cf)and vermicompost(CVC)were computed using the field experimental data.Making use of these basic parameters,the fertilizer prescription equations were developed under NPK alone and under IPNS for the desired yield targets of Sesamum for a range of soil test values.The quantity of fertilizers contributed by the application of vermicompost was assessed.Nutrient requirement to produce 100 kg of sesame seed was worked out to be 10.20 kg N,3.90 kg P2O5 and 5.22 kg K2O.In the present investigation,the requirement of N was higher which is followed by K2O and P2O5.The requirement of N was 2.62 times higher than P and 1.95 times higher than K.The percent contribution of N,P and K was 12.25,15.75 and 6.00 from soils,41.68,22.85 and 59.97 from fertilizer and 9.87,6.74 and 18.65 from organic manures,respectively.Thus the Inductive cum Targeted Yield Model used to develop fertilizer prescription equations provides a strong basis for soil fertility maintenance consistent with high productivity and efficient nutrient management in farming for sustainable and enduring agriculture.

Utilization of Nano Rock Phosphate by Maize （Zea mays L.） Crop in a Vertisol of Central India

An attempt was made in the present investigation to utilize the vast deposit of rock phosphate （RP） of India by preparing nano RP using modem tool of nano-science and nano-technology for field application to maize crop （Zea mays L.）. To evaluate the efficacy of different nano RP, a field experiment was conducted during kharif season （June to September） of 2012 at India Institute of Soil Science （IISS）, Bhopal, taking maize as a test crop. The experiment consisted of five treatments （control, NK （100%）, NPK （100%）, NK （I00%） ＋ 60 kg P205） as nano RP through Udaipur nano RP （34% P205） and Udaipur nano RP （31% P205） were tested in randomized block design with four replications. The results showed that the shelling percentage, 1,000 grain weight, grain and stover yield, etc., were significantly higher in the maize plant treated with Udaipur nano RP （34% P205） as compared to the control, which was being at par with single super phosphate （SSP） treated plants. The total P content and its uptake were higher （0.65% and 40.29 kg/ha） in SSP treated plant, which was closely followed by Udaipur nano RP 34% （0.63% and 38.29 kg/ha） over the control （0.60% and 27.82 kg/ha）. The SSP treated plants had significantly highest apparent P recovery （47.98%） which was comparable to Udaipur nano RP （34% P205）, where as the Udaipur nano RP （31% P205） had the lowest. The additional N and K uptake by the plant was also observed with application of P sources, which were ranged from 16.5 kg/ha to 37.2 kg/ha and 27.9 kg/ha to 64.7 kg/ha under different P treatments. These results showed that crop utilization of P from nano RP was at par with that of P from SSP while yield response to P from nano RP was marginally lower than to P from SSP but serve as a cheaper source.

Effect of Copper Oxide Nano Particle on Seed Germination of Selected Crops

Nano particles are finding their way into the environment through deliberate and accidental actions, ecotoxicological properties and the risks of these nano particles have yet not been fully characterized. In this present investigation, experiments were carried out to know the effect of Cu oxide-nano particles （〈 50 nm） on germination and growth of seeds of soybean and chickpea. In both the crops, germination was not checked up to 2,000 ppm Cu （applied through Cu oxide-nano particles）, but the root growth was prevented above 500 ppm Cu. With increasing concentration of NPs, the elongation of the roots was severely inhibited as compared to that in control. In many cases root necrosis was occurred. Massive adsorption of Cu oxide-nano particles into the root system was responsible for the toxicity. A parallel experiment was also carried out to know the effect of copper sulphate solution on seed germination, above 200 ppm Cu, it restricted the germination of seeds, because of high salinity.

Total and Extractable Manganese and Iron in Some Cultivated Acid Soils of India:Status,Distribution and Relationship with Some Soil Properties

A total of 400 surface soil （0-15 cm） samples were collected from cultivated soils representing four soil series, namely, Hariharapur, Debatoli, Rajpora and Neeleswaram in Orissa, Jharkhand, Himachal Pradesh and Kerala states of India, respectively, and were analyzed to measure the contents of total and extractable Mn and Fe, to establish the relationship among total and extractable Mn and Fe and soil properties, and to characterize the spatial distribution pattern of Mn and Fe in some cultivated acid soils of India. The contents of total as well as extractable Mn and Fe varied widely with extractants and soil series. However, the amounts of Mn or Fe extracted by diethylene triamine penta-acetic acid （DTPA）, Mehlich 1, Mehlich 3, 0.1 mol L-1 HC1 and ammonium bicarbonate DTPA （ABDTPA） were significantly correlated with each other （P 〈 0.01）. Based on the DTPA-extractable contents and the critical limits （2 mg Mn kg-1 soil and 4.5 mg Fe kg-1 soil） published in the literature, Mn and Fe deficiencies were observed in 7% 23% and 1%-3% of the soil samples, respectively. The content of soil organic carbon （SOC） had greater influence on total and DTPA-extractable Fe than did soil pH. Geostatistical analysis revealed that total and DTPA-extractable Mn and Fe contents in the acid soils were influenced by soil pH, SOC content, and exchangeable cations like potassium, calcium and magnesium. Spatial distribution maps of total and DTPA-extractable Mn and Fe in soil indicated different distribution patterns.

Assessment of long-term climate variability and its impact on the decadal growth of horticultural crops in central India

Background:The impact of climate change on horticultural production is of utmost concern worldwide.One such vulnerable region of horticultural importance is the Madhya Pradesh state in the central part of India.It is crucial to analyse the long-term trend in climatic variations and its effect on horticultural crop production.Therefore,this study focuses on detecting trends in mean annual precipitation and temperature of 115 years for the 15 districts covering all the regions of the state as well as projections of all the Representative Concentration Pathway(RCP)climatic scenarios for 2050 and 2080 of Madhya Pradesh state.The decadal(2010–2020)insight into the area and production of horticultural crops is undertaken which will help forecasting the future growth trend.For a better insight,case study on four horticultural crops is undertaken to assess their decadal growth trend vis-à-vis climate parameters in these 15 districts.Results:The Mann–Kendall test for 1901–2016 and Sen’s slope indicated a non-significant change in long-term trend for precipitation except for increasing change in Khargone and decreasing change in Rewa districts.Signifi-cant increasing trend of average temperature is obtained for Hoshangabad,Jabalpur,Sagar and Rewa districts.The Sen’s slope indicated an increase of 0.005 to 0.009℃for maximum temperature and 0.005 to 0.012℃for minimum temperature annually.The projections of all the RCP climate scenarios for the years 2050 and 2080 indicated non-significant variation in precipitation but an increase in maximum(1.4 to 4.1℃)and minimum(1.45 to 4.65℃)annual temperatures.An increasing trend in area and production for horticultural crops is also observed in central India for the study period.There is yield increase in all the crops selected in case study except for potato,which recorded a decreased yield between the years 2010–2015.Conclusion:The Mann–Kendall test and projections indicate towards climate change with a temperature rise.Though the decadal study indicates an increasing trend in horticultural crops,the districts identified to be affected by climate change need to have a plan to lessen the horticultural loss in the state.This study contributes to understand-ing the future climate change trends and its impact on horticultural crop production to formulate various adaptation strategies.

Assessment of ecosystem services of rice farms in eastern India

Background:Rice is a major cereal crop and staple food of eastern India,and most farmers depend solely on rice for their livelihood.Rice farming provides both tangible and non-tangible benefits to ecosystems which need to be maintained and enhanced.These benefits are provided through ecosystem services(ES)that include both marketable and non-marketable.Methods:In this study,the rice farms in eastern India were valued by quantifying the economic value of the services under conventional method of rice cultivation and the gap of ecosystem services value and farm income per unit area were assessed.A stratified random sampling technique was used in this study for selection of agro-climatic zones,districts,blocks,gram panchayat,and study units(households).Soil sampling was also performed for assessing the regulating services(biocontrol of pests,carbon flow,soil erosion,nitrogen fixation),provisioning services(food and by-products),and supporting services(soil fertility,hydrological flow,nutrient cycling,and soil formation).Results:The results indicated that the total economic value of ecosystem services ranged from US$1238 to 1688 ha−1 year−1.The marketed(primary production)and non-marketed ecosystem services values ranged from 66–89 to 11–34%of the total,respectively.Valuation of some of the ecosystem services such as cultural services,biodiversity,and gas regulation,which may play a significant role in total ecosystem services,has not been made due to non-availability of data and appropriate methodology for rice ecosystem.Different values of parameters can explain the variability in ecosystem services among the agro-climatic zones in eastern India.Clustering of locations based on variability of ecosystem services helps in identifying intervention points for sustaining and improving ecosystem services,while permitting sustainable agro-ecological intensification.The highest total economic gap between ES value and farm income was found in the north central plateau zone(US$1063 ha−1 year−1)and the lowest in the north western plateau zone(US$670 ha−1 year−1).Conclusion:We suggest various measures to reduce the economic gap,including payments for ecosystem services for rice farming for sustainability of the ecosystem and agricultural development,while ensuring reliable farm income.

Microbial Populations,Activity and Gene Abundance in Tropical Vertisols Under Intensive Chemical Farming

There are increasing concerns on the environmental impacts of intensive chemical agriculture. The effect of high agrochemical inputs used in intensive chemical farming was assessed on soil microbiological, molecular and biochemical properties in tropical Vertisols in India. Farm field sites under normal cultivation of arable crops using high inputs of fertilizers and pesticides in chili （Capsicum annum L., 5.0× dose for fertilizers and 1.5× dose for pesticides over normal inputs） and black gram （Vigna mungo L. Hepper, 2.2× dose for fertilizers and 2.3× dose for pesticides over normal inputs） were compared with adjacent sites using normal recommended doses. Organic carbon and basal respiration showed no response to high inputs of fertilizers and pesticides in soils of both crops. Labile carbon decreased by 10% in chili soils and increased by 24% in black gram soils under high input farming system. The proportion of soil labile carbon as a fraction of soil organic carbon was unaffected by high inputs. The labile carbon mineralization coefficient （qMLc） increased by 50.0% in chili soils, indicating that the soil microorganisms were under stress due to high agochemical inputs, whereas qMLc decreased by 36.4% in black gram soils. Copiotrophs increased due to high inputs in soils of both chili （63.1%） and black gram （47.1%）. Oligotrophs increased by 10.8% in black gram soils but not in chili soils. The abundance of amoA gene reduced by 39.3% in chili soils due to high inputs and increased significantly by 110.8% in black gram soils. β-Glucosidase also increased by 27.2% and 325.0%, respectively. Acid phosphatase activity reduced by 29.2% due to high inputs in chili soils and increased by 105.0% in black gram soils. The use of high agrochemical inputs thus had adverse consequences on biological health in chili but not in black gram soils. In soils cultivated with black gram, the moderating effect of cultivating legumes and their beneficial effect on soil health were evident from the increase in soil labile carbon, lower qMLc, higher amoA gene and enzyme activities. Overall results showed that cultivation of legumes permits intensive chemical farming without deteriorating soil biological health.