Improving fertilizer recommendations for Nepalese farmers with the help of soil-testing mobile van

Smallholder farmers dominate agriculture in Nepal. These farmers have poor knowledge about agriculture and lack of support for soil management and integrated plant-nutrient systems. Focusing on the importance and need for soil-fertility management, a soil-testing mobile van program has recently been introduced in Nepal by Soil Management Directorate, Hariharbhawan. With the introduction of the mobile lab, famers can get their soil tested for nutrient deficiencies and fertilizer requirements at their doorsteps. Using mobile lab, spatial distributions of chemical properties, including pH, organic matter (OM), total nitrogen (N), available phosphorus (as P₂O₅), and available potassium (as K₂O) were examined in soil samples taken from the 0 to 15 cm depth from selected agricultural fields in eight different districts in the mid-hills and Terai regions of Nepal. Tests conducted on 1,479 soil samples in the soil-testing mobile van revealed the following: the mean soil OM ranged from 0.01 to 1.77%; total N content ranged from 0.01 to 0.08%; mean available P₂O₅ ranged from 16.47 to 197.82 kg ha^?1; and mean available K₂O ranged from 84.3 to 422.57 kg ha^?1. For each crop to be grown, farmers were provided with individual soil health reports and fertilizer recommendations (rate, amount, and type). This program not only allows scientists and farmers to work closely and share information but also serves as a model for the nation to successfully transfer technology for improving soil health and sustainability.     

Effect of dietary Sargassum wightii and its fucoidan-rich extract on growth,immunity, disease resistance and antimicrobial peptide gene expression in Labeo rohita

International Aquatic Research - This work aimed to appraise growth performance, immune responsiveness, bacterial disease resistance and mRNA expression of two antimicrobial peptides in Labeo...     

Dietary ascorbic acid requirement for growth of striped catfish,Pangasianodon hypophthalmus (Sauvage, 1878) juveniles

A sixty‐day feeding trial was conducted to determine the ascorbic acid (AA) requirement for growth of striped catfish, Pangasianodon hypophthalmus juveniles. Seven iso‐nitrogenous and iso‐energetic (370 g protein per kg and 19.6 MJ/kg) purified diets were prepared with different levels of ascorbic acid such as control (0), T₁ (17.5), T₂ (35), T₃ (70), T₄ (175), T₅ (350) and T₆ (700) mg ascorbic acid (L‐ascorbyl‐2‐polyphosphate) equivalent per kg diet. Fish with a mean body weight of 3.2–3.4 g were stocked (fifteen fish per tank) in triplicates following a completely randomized design. Each group was fed to satiation twice a day for 60 days. Significant differences were observed in growth, survival, body composition and metabolic enzymes activities with different dietary ascorbic acid levels. Maximum weight gain, specific growth rate (SGR) and protein efficiency ratio (PER) were found in fishes fed with 35 mg AA per kg diet, supported by best feed conversion. Fish fed a diet containing vitamin C had the highest activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) compared to those fed with vitamin C‐depleted diets. In this study, based on using broken‐line regression analysis, the dietary vitamin C requirement for growth of P. hypophthalmus juveniles was estimated to be in the range of 46–76 mg AA per kg, depending on the criterion used, growth and liver storage. Our results will be helpful for the formulation of cost‐effective ascorbic acid incorporated diets for striped catfish, P. hypophthalmus.     

Retrieval of rice crop growth variables using multi-temporal RISAT-1 remotely sensed data

Microwave remote sensing sensors have great potential due to their capability to operate in any weather condition for the wide range of agricultural applications. The rice crop variables such as leaf area index (LAI) and plant height (PH) were retrieved for the monitoring of crop growth to improve crop production. The interaction of rice crop variables with medium spatial resolution (25 m) Radar Imaging Satellite-1 (RISAT-1) data for Varanasi district, India, was examined. The multi-temporal dual polarization (HH- and HV-) images having frequency 5.35 GHz at C-band were investigated. Crop growth profile derived from the analysis of temporal backscattering (July–October, 2013) showed 3–4 dB difference throughout its growth cycle. The rice crop variables were retrieved by the inversion of polynomial models and showed higher values of coefficient of determination (R²) for HH-polarization in comparison to HV-polarization.     

Antixenosis and antibiosis mechanisms of resistance to pod borer, <Emphasis Type="Italic">Helicoverpa armigera</Emphasis> in wild relatives of chickpea, <Emphasis Type="Italic">Cicer arietinum</Emphasis>

The noctuid pod borer, Helicoverpa armigera is one of the most damaging pests of chickpea, Cicer arietinum. The levels of resistance to H. armigera in the cultivated chickpea are low to moderate, but the wild relatives of chickpea have exhibited high levels of resistance to this pest. To develop insect-resistant cultivars with durable resistance, it is important to understand the contribution of different components of resistance, and therefore, we studied antixenosis and antibiosis mechanisms of resistance to H. armigera in a diverse array of wild relatives of chickpea. The genotypes IG 70012, PI 599046, IG 70022, PI 599066, IG 70006, IG 70018 (C. bijugum), ICC 506EB, ICCL 86111 (cultivated chickpea), IG 72933, IG 72953 (C. reticulatum), IG 69979 (C. cuneatum) and IG 599076 (C. chrossanicum) exhibited non preference for oviposition by the females of H. armigera under multi-choice, dual-choice and no-choice cage conditions. Based on detached leaf assay, the genotypes IG 70012, IG 70022, IG 70018, IG 70006, PI 599046, PI 599066 (C. bijugum), IG 69979 (C. cuneatum), PI 568217, PI 599077 (C. judaicum) and ICCW 17148 (C. microphyllum) suffered significantly lower leaf damage, and lower larval weights indicating high levels of antibiosis than on the cultivated chickpea. Glandular and non-glandular trichomes showed negative correlation with oviposition, while the glandular trichomes showed a significant and negative correlation with leaf damage rating. Density of non-glandular trichomes was negatively correlated with larval survival. High performance liquid chromatography (HPLC) fingerprints of leaf surface exudates showed a negative correlation of oxalic acid with oviposition, but positive correlation with malic acid. Both oxalic acid and malic acid showed a significant negative correlation with larval survival. The wild relatives exhibiting low preference for oviposition and high levels of antibiosis can be used as sources of resistance to increase the levels and diversify the basis of resistance to H. armigera in cultivated chickpea.     

Streptomyces sp. RP1A-12 mediated control of peanut stem rot caused by Sclerotium rolfsii

Sclerotium rolfsii Sacc. is a destructive soilborne fungal pathogen with a wide host range that includes peanuts. Biological control offers an interesting alternative to fungicides for sustainable management of soilborne diseases. The current investigation is aimed at evaluating one potential biocontrol agent Streptomyces sp. RP1 A-12 for growth promotion and the management of peanut stem rot disease caused by S. rolfsii under field conditions. Preliminary studies conducted under in vitro and the greenhouse conditions showed promising results against the stem rot pathogen. Further in vitro and pot experiments conducted to assess Streptomyces sp. RP1 A-12 for its growth promoting abilities using whole organisms have shown an increase in seed germination, root and shoot length. Other parameters like nodule number and plant biomass were also significantly increased over control treatments indicating that the test bioagent possesses growth promoting abilities along with disease suppression capabilities. Subsequently field studies were carried out for two consecutive rainy seasons. The bioagent was applied as whole organism and partially purified crude metabolites. Results indicate the bioagent reduced stem rot disease incidence by 64–67% and 22–49% respectively in two field trials conducted with notable increase in yield. Partially purified Streptomyces sp. RP1 A-12 metabolites exhibited an even greater effect in reducing the incidence and severity of stem rot compared to the pathogen inoculated control.     

Response of baby corn genotypes to soil and foliar nitrogen application schedule

Responsive genotypes, timing and mode of nitrogen application are important for realizing potential yield of winter baby corn. Soil application of nitrogen is a common practice. Foliar application enhances absorption and utilization of nitrogen particularly after anthesis. We investigated combined approach in management of nitrogen for the first time including soil applications followed by foliar urea spray to enhance baby corn yield and profitability. To determine these, 2-year study conducted with three genotypes and six schedules of recommended dose of nitrogen (RDN). Growth characters, productivity traits, harvest period and yields recorded. Nitrogen content and uptake, protein content and harvest were determined. Genotype HM-4 produced 4.6% and 4.1% more cobs and corn weight over HQPM-1. Combined approach resulted higher yield attributes, yields, N uptake, protein harvest and monetary returns. RDN in 4 splits with more basal (B) dose increased cob and corn yield by 4.8% and 5.1% than 3 splits (50% B). Results suggest that HM-4 be grown using RDN 50% as B, 25% at knee height stage, 20% at tassel emergence followed by 5% foliar spray after first picking as urea solution (3%) for achieving higher yield and net returns. More studies needed under diverse conditions.     

Ethnobotanical studies of the dwindling aboriginal Jarawa tribe in Andaman Islands,India

World over the traditional knowledge has always formed the foundation for development of modern medicines as a result of scientific follow up of the traditional knowledge. Andaman archipelago represents one of the greatest emporia of ethno botanical wealth in India where aboriginal native tribes of ancient culture remain in their virginity and possess abundant ethnic knowledge. The Jarawas of Andaman Island are one such primitive and dwindling community. Jarawas inhabit the Jarawa Reserve located along the western parts of the South and Middle Andamans. A brief account of anthropology of the tribe is given. Results of ethnobotanical studies of Jarawa tribe have been enumerated which revealed interesting plants which can be further prioritized for scientific evaluation and Bioprospection for product development. The species like Alpinia manii, Amomum aculeatum, belonging to Zingiberaceae and Pseuduvaria prainii, Orophea katschallica of Annonaceae are shown to have effective insect and bee repellent properties. Such leads should be subjected to further scientific scrutiny for development of global level products having mosquito and other disease causing insect repellent properties. While this achieves the human welfare aspects, at the same time boosts the economy of the region. The Jarawas possess extensive knowledge of the plants of the surrounding forests and use them in their daily life for food, medicine, shelter, fibres, ornaments, bows and arrows and for many other needs. Such plants are enumerated with correct botanical names, family, Jarawa names, plant parts used along with details of use.     

Controlled-environment and field evaluation of heat stress induced genetic variability on translocation efficiency and grain filling traits in rice

Journal of Crop Science and Biotechnology - The grain filling of rice is gets weakened by heat stress due to reduced spike photosynthesis at high temperature stress. An alternate source of carbon...