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Highly weathered laterite soils are a characteristic feature of humid tropics with undulating topography and high rainfall. The crop of cashew (Anacardium occidentale L.) has been cultivated in such landscapes, mainly to prevent further degradation due to the drought hardiness of cashew and requirement of very limited soil disturbances for its cultivation. Providing proper nutrient management is important for balancing the nutrient removal by tree crops especially in poor fertile soils. A study was initiated, after 5 years of application of inorganic fertilisers and organic amendments to cashew in a weathered tropical soil, to evaluate the effects of organic and inorganic sources of nutrients on soil aggregation and biochemical characteristics. The experiment consisted of 11 treatments as Farm Yard Manure (FYM) alone; FYM + biofertiliser consortia; FYM, rock phosphate and wood ash; poultry manure; In situ composting using recyclable cashew biomass and weeds; In situ composting using recyclable cashew biomass and weeds + green manuring; vermicomposting of recyclable cashew biomass; FYM + organic cakes + recyclable cashew biomass + biofertiliser consortia; recommended dose of nitrogen, phosphorus and potassium fertiliser (NPK fertiliser); recommended NPK fertiliser + FYM; and control without nutrient application. Soil samples were collected from surface 0–30 cm layer. The soil samples were fractionated into three aggregate sizes, i.e., >2 mm (large macroaggregates), 0.25–2 mm (small macroaggregates), 0.053 to 0.25 mm (microaggregates) and

Cashew apple pomace, a major byproduct of cashew plantations and processing units, has the potential to be used as a vital source of nutritive components. The present study aims in the utilization of this pomace powder as a biofortifying agent during the preparation of cereal based extrudates. Enrichment of cereal extrudates was done by supplementing rice flour with cashew apple pomace powder (CAPP) at a rate of 0–25 per cent and it was found to considerably improve their biochemical properties. The incorporation of CAPP as an ingredient in the cereal based extrudates had significantly increased their ash, starch, protein and overall mineral content excluding phosphorous and boron content. Incorporation of CAPP in the extrudates significantly improved the phenolic (4.00 mg gallic acid equivalents g−1), flavonoid (0.35 mg catechin equivalents g−1) and total antioxidant activities (5.34 mg ascorbic acid equivalents g−1), over the cereal based control group. The colour parameters viz. hue and chroma were also found to be high with the CAPP incorporated extrudates. The hydrophilic nature of the CAPP reduced the compactness of pores, cavity space and increased the pore wall thickness in the extrudates. Dearth in textural properties i.e., firmness, work of extrusion, cut force and other physical properties i.e., expansion ratio, bulk density and the specific length was observed as a result of an increase in the rate of CAPP incorporation in the feed flour. Sensory scoring using nine-point hedonic scale indicated that CAPP can be incorporated in the range of 5–15 per cent for the snack purpose while >20% incorporation could be done for fish, poultry and other animal feed extrudates.

Zero tillage management of agricultural soils has potential for enhancing soil carbon (C) storage and reducing greenhouse gas emissions. However, the mechanisms which control carbon (C) sequestration in soil in response to zero tillage are not well understood. The aim of this study was to investigate the links between zero tillage practices and the functioning of the soil microbial community with regards to C cycling, testing the hypothesis that zero tillage enhances biological functioning in soil with positive implications for C sequestration. Specifically, we determined microbial respiration rates, enzyme activities, carbon source utilization and the functional chemistry of the soil organic matter in temperate well drained soils that had been zero tilled for seven years against annually tilled soils. Zero tilled soils contained 9% more soil C, 30% higher microbial biomass C than tilled soil and an increased presence of aromatic functional groups indicating greater preservation of recalcitrant C. Greater CO2 emission and higher respirational quotients were observed from tilled soils compared to zero tilled soils while microbial biomass was 30% greater in zero tilled soils indicating a more efficient functioning of the microbial community under zero tillage practice. Furthermore, microbial enzyme activities of dehydrogenase, cellulase, xylanase, β-glucosidase, phenol oxidase and peroxidase were higher in zero tilled soils. Considering zero tillage enhanced both microbial functioning and C storage in soil, we suggest that it offers significant promise to improve soil health and support mitigation measures against climate change.

Soil aggregation is an important physical property that influences the physico-chemical and biological properties of soil. Soil disturbances such as tillage can have a significant effect on soil aggregation. This study sought to examine the effect of soil aggregate size on soil pore characteristics and the subsequent effect on emission of greenhouse gases (GHGs) for both sandy loam and clay loam soils. Columns of aggregates in the size ranges of 2–4 mm, 1–2 mm, 0.5–1 mm and 2 and CH 4 flux was significantly affected by size of aggregates. Clay loam soils emitted the most CO 2 from the small sized aggregates, whereas in sandy loam soils the larger aggregates produced the maximum CO 2 flux. Smaller aggregates produced higher CH 4 flux in both soil textures. No significant difference between aggregate sizes and soil textures was found for N 2 O fluxes. Soil pore characteristics such as porosity and pore size significantly affected fluxes of GHGs such as CO 2 and CH 4 . These results indicate that management practices such as tillage that heavily influence soil aggregation and pore characteristic development can have a direct impact on emission of greenhouse gases and subsequently have implications for global warming.