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Nutrient management plays a key role in the productivity and sustainability of land resources. Balanced application of mineral nutrition to the crops not only helps to realise increased yields but also to prevent land degradation. Cashew is generally grown as a rainfed crop in tropical regions with limited attention on nutrient management. Making an informed decision on the scientific aspects of the nutrient application in terms of the right amount, time and place of application are important for the growers. The mobile apps come handy in this direction because the farmers can themselves find out nutrient management schedule as per the field conditions. A mobile app for nutrient management in cashew was developed which takes care of varied field situations of farmers and was demonstrated in the farmer’s fields under participatory research mode. The app helped farmers to devise their own site-specific nutrient management. The field implementation for the site-specific nutrient management with the help of a mobile app showed improvement in soil and leaf nutrient status as well as the raw cashewnut yield. The yield improvement was in the range of 58 to 67% and the BC ratio was increased by 9 to 47% compared to the initial status. The mobile app DCR-Cashew Nutrient Manager was useful to empower the farmers, and field implementation was beneficial to improve the productivity, income and ecosystem sustainability by improving the nutrient balance in the soil.

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

To assess the effect of planting density and irrigation in cashew (Anacardium occidentale L.) during its critical growth stages such as flowering and fruit set on, growth, yield, water-use efficiency and farm income, a field experiment was initiated in a split-plot design in 2011 at Puttur, Karnataka, India. The main plot consisted of three planting densities namely, 5 × 4 m, 6 × 4 m and 10 × 5 m. The irrigation treatments were imposed in subplots as, irrigation at 60% cumulative pan evaporation (CPE), at 40% CPE, at 20% CPE, irrigation once in 15 days, soil and water conservation technique, and control (without any irrigation or soil water conservation technique). The results indicated that the growth, raw cashew nut yield and net income during 5th and 6th year of plantation of cashew increased with increase in planting density per unit area. The average increase in nut yield under high density planting ranged from 75 to 81% compared to normal density planting. Irrigation using drip system from December to March at 20% CPE and 40% CPE was beneficial to increase the nut yield by 53.5% and 34.1% compared to control. The yield increase under soil and water conservation practice was 12.9%, and 59.7% under irrigation once in 15 days. The increased planting density was beneficial to increase the net income and benefit–cost ratio. The deficit irrigation practices were useful to increase the water-use efficiency in cashew. Widely spaced trees showed increased water-use efficiency compared to high-density planting. Overall, the study demonstrated the usefulness of increased planting density and appropriate irrigation practices to increase yield and net income from cashew orchards.

Fruit tree crops are an essential part of the food production systems and are key to achieve food and nutrition security. Genetic improvement of fruit trees by conventional breeding has been slow due to the long juvenile phase. Advancements in genomics and molecular biology have paved the way for devising novel genetic improvement tools like genome editing, which can accelerate the breeding of these perennial crops to a great extent. In this article, advancements in genomics of fruit trees covering genome sequencing, transcriptome sequencing, genome editing technologies (GET), CRISPR-Cas system based genome editing, potential applications of CRISPR-Cas9 in fruit tree crops improvement, the factors influencing the CRISPR-Cas editing efficiency and the challenges for CRISPR-Cas9 applications in fruit tree crops improvement are reviewed. Besides, base editing, a recently emerging more precise editing system, and the future perspectives of genome editing in the improvement of fruit and nut crops are covered.

The development of salinity affects 7% of the world’s land surface, acting as a major constraint to crop productivity. This study attempted to use the co-evolving endophytes of peanut to alleviate salinity stress and enhance the yield of peanut. Diverse and different tissue colonizing endophytes were isolated from peanut and screened in vitro by seed germination bioassay imposing gradients of salinity, with two cultivars TG37A (susceptible) and GG2 (moderately resistant), in potted conditions using saline irrigation water. Finally, nine endophytes capable of producing IAA and ACC-deaminase, promoting root growth and yield in potted conditions were selected for further evaluation in field conditions. They were evaluated with saline water (1.5–2.0 dS/m) in saline soil with susceptible cultivar TG37A. Simultaneously, three endophytes (Bacillus firmus J22N; Bacillus tequilensis SEN15N; and Bacillus sp. REN51N) were evaluated with two cultivars, GG2 and TG37A, during rainy and post-rainy seasons with elevated salinity. The application of endophytes like Bacillus firmus J22N and Bacillus sp. REN51N enhanced the pod and haulm yield of peanuts by 14–19% across cultivars, salinity, and seasons. In addition, there was significant modulation in parameters like relative water content; production of enzymes like superoxide dismutase (SOD), glutathione reductase (GR), catalase (CAT), ascorbate peroxidase (APX), lipid peroxidase (POD), and H2O2 content in leaf; and uptake of potassium. The activities of the enzymes involved in scavenging reactive oxygen species (ROS) increased with salinity, and further increased with endophytes like Bacillus firmus J22N, Bacillus tequilensis SEN15N, and Bacillus sp. REN51N. There was an enhanced accumulation of proline, reduced level of phenol and H2O2, and enhanced uptake of potassium with the inoculation of endophytes. This improved scavenging capacity of plants by endophytic modulation of ROS scavengers, uptake of K, production of ACC deaminase and IAA, root and biomass growth, modulation in relative water content, and enhanced accumulation of osmoprotectant might be the reasons of alleviation of salinity stress. Endophytes could have alleviated salinity stress in peanuts, indicating the mechanisms and potential of peanuts at the field level. These endophytes could be applied to bring agricultural sustainability to salinity-affected areas in the future. Furthermore, few genera viz. Kocuria, Brevundimonas, Agrococcus, Dietzia, and Kytococcus were observed in peanut tissue for the first time.

Sub-optimal productivity in cashew is common in tropical India due to inadequate attention on plant nutrient management. Identifying the nutrient constraints, its diagnosis and management are important for maximizing production in a sustainable manner. We established nutrient diagnostic norms for cashew that shall be useful for quick diagnosis of the nutrient requirement of cashew for devising rapid nutrient management schedule to improve the productivity. The optimal leaf nutrient status in cashew for nitrogen, phosphorus, potassium, calcium, magnesium and sulfur ranged from 2.23 to 2.82, 0.13 to 0.18, 0.91 to 1.47, 0.92 to 1.39, 0.46 to 0.70 and 0.75 to 1.14% respectively. The optimal leaf status for micronutrients such as iron, manganese, zinc, copper, boron and molybdenum ranged as 285 to 398, 200 to 409, 54 to 74, 47 to 60, 22 to 46 and 3.0 to 4.4 mg kg−1. The regional survey on soil and leaf nutrient status of cashew in prominent cashew growing areas along coastal India revealed the nutrient constraints causing lower productivity levels. The cashew growing soils in India were predominantly deficient in nitrogen, potassium, calcium, magnesium, zinc and copper. The study indicated the ill effects of neglect of fertilizer and manure application in cashew on soil organic carbon, nitrogen and potassium, which adversely affected the nutrient uptake by cashew as evident from the leaf nutrient status. The study also highlighted the need to pay attention to soil ameliorants to correct soil acidity to make available calcium, magnesium and micronutrients such as zinc, copper and manganese.

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.

This study aimed at identification of abrupt change points (CPs) and detection of gradual trends in 34-year (1980–2013) annual rainfall at nine stations of an Indian arid region. The CPs were determined by five tests and their significance was examined by two tests. Furthermore, trends were tested by three tests and their magnitudes were quantified by two tests. Novelty of the study lies in investigating significance of trends sequentially over years by applying Mann–Kendall (M–K) test. The identified CPs were similar for standard normal homogeneity test and cumulative deviations test at most stations. In contrast, Pettitt and Bayesian tests detected CP in years 2002 and 2005 at six and three stations, respectively, and their significance was verified. Results of sequential M–K test did not match with other tests' results. The mean annual rainfall after CP (350–627 mm) increased by 14–80% of the amount before CP (306–444 mm) with 7–42% reduction in coefficient of variation. The box–whisker plots supported these findings. Results of trend tests indicated statistically significant trends at Anjar, Bhachau, Mandvi and Rapar. Trend magnitudes by linear regression prior to CP (−6.2 to 7.1 mm year−1) showed an overall increase after CP (4.7–40.8 mm year−1) with negative trend at one station. Sen's slope test, showing good harmony with linear regression, revealed that trend magnitudes after CP were 2–10 times higher than that for 34-year period at six stations. Results of M–K test applied for sequential periods emphasized that rainfall trends are becoming stronger over time. This finding suggests that significance level of increasing rainfall trends may further increase in future. Finally, findings of this study are useful for planners and decision makers for developing policies to meet the challenges of the heightened rainfall in study area. Also, the approach used here may be adopted in other parts of the globe.

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.

SUMMARYThe benefits of reduced and zero-tillage systems have been presented as reducing runoff, enhancing water retention and preventing soil erosion. There is also general agreement that the practice can conserve and enhance soil organic carbon (C) levels to some extent. However, their applicability in mitigating climate change has been debated extensively, especially when the whole profile of C in the soil is considered, along with a reported risk of enhanced nitrous oxide (N2O) emissions. The current paper presents a meta-analysis of existing literature to ascertain the climate change mitigation opportunities offered by minimizing tillage operations. Research suggests zero tillage is effective in sequestering C in both soil surface and sub-soil layers in tropical and temperate conditions. The C sequestration rate in tropical soils can be about five times higher than in temperate soils. In tropical soils, C accumulation is generally correlated with the duration of tillage. Reduced N2O emissions under long-term zero tillage have been reported in the literature but significant variability exists in the N2O flux information. Long-term, location-specific studies are needed urgently to determine the precise role of zero tillage in driving N2O fluxes. Considering the wide variety of crops utilized in zero-tillage studies, for example maize, barley, soybean and winter wheat, only soybean has been reported to show an increase in yield with zero tillage (7·7% over 10 years). In several cases yield reductions have been recorded e.g. c. 1–8% over 10 years under winter wheat and barley, respectively, suggesting zero tillage does not bring appreciable changes in yield but that the difference between the two approaches may be small. A key question that remains to be answered is: are any potential reductions in yield acceptable in the quest to mitigate climate change, given the importance of global food security?

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.

Soil tillage practices have a profound influence on the physical properties of soil and the greenhouse gas (GHG) balance. However there have been very few integrated studies on the emission of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) and soil biophysical and chemical characteristics under different soil management systems. We recorded a significantly higher net global warming potential under conventional tillage systems (26–31% higher than zero tillage systems). Crucially the 3-D soil pore network, imaged using X-ray Computed Tomography, modified by tillage played a significant role in the flux of CO2 and CH4. In contrast, N2O flux was determined mainly by microbial biomass carbon and soil moisture content. Our work indicates that zero tillage could play a significant role in minimising emissions of GHGs from soils and contribute to efforts to mitigate against climate change.

An experiment was conducted in micro-plots filled with sandy loam soil having 14% clay and 0.33% organic carbon to see the responses of halophytic grasses Sporobolus marginatus and Urochondra setulosa collected from the extreme saline-sodic Kachchh plains, Bhuj, Gujarat, India under alkalinity/salinity. Maximum photosynthetic rate was recorded in control treatment. Photosynthetic rate decreased at pH 9.0 + EC 20 dS/m (11.25 and 17.8 μmol CO2/m2/s) in S. marginatus and U. setulosa respectively, along with reduction in stomatal conductance and transpiration rate. In comparison to control, increased accumulation of total soluble sugars and proline may be due to increased osmotic adjustment for both halophytes. Similarly, at mixed stress of pH 9.0 with EC 20 dS/m, the epicuticular wax load increased in both S. marginatus and U. setulosa (24.0 and 40.0 mg/g). A positive correlation of stress was seen with Na+ and Cl‑ content while negative correlation with K+ content. Na+ content increased to about 3-7 fold at salinity level, EC 35 dS/m. Similarly, with treatment of mixed stress of pH 9.0 with saline level EC 20dS/m, 3-6 times increase in Na+ with decrease in K+ was observed in S. marginatus and U. setulosa respectively. These grass species maintained better gas exchange properties with higher osmolytes accumulations and balanced ionic relations under high stress conditions of salinity and alkalinity. These attributes might be providing physiological adaptable mechanisms for growth under salt affected environments.