Biofloc technology is a modern-day high-density fish culture system employing heterotrophic conversion of nitrogenous waste into useful flocs for water quality control and improved welfare. However, optimization of the stocking density for the target species during seed rearing is the key to a successful farming operation. The study evaluated the effect of different stocking density on the growth, feed utilization, digestive physiology and economics in a biofloc-based seed rearing of butter catfish, O. bimaculatus. Advanced fry (1.21 ± 0.08 g) was reared in a zero-water exchange biofloc system for 90 days at stocking densities of 0.5 g/L(T1), 1.0 g/L(T2), 1.5 g/L(T3) and 2.0 g/L(T4). The observed water quality indicates a reduction in DO and pH in T4, while the total ammonia nitrogen and nitrite levels remained low in T1. Among the groups, highest weight gain was noticed in the lowest stocking density (0.5 g/L) (p < 0.05), which coincides with a better feed conversion ratio. Similarly, the digestive enzyme (protease, amylase, and lipase) secretion was higher in T1. Profitability assessment describes the possibility of low profit in T4, in the case where the fish’s sale price is based on harvested size. T1 showed higher individual growth and higher profit. Overall, a low stocking density of 0.5 g/Lis optimum for augmenting growth, feed utilization, physiological function and economic performance of O. bimaculatus. The study provides direction for a low-stocking oriented ecological and economically sustainable method of seed production of butter catfish in a biofloc system.

Under changing climate, identification and diversification of cropping systems having higher stress resilience and adaptability for fragile mountain ecosystems of Eastern Himalayan Region (EHR) are paramount. Lesser known and underutilized crop like buckwheat (BW) with year-round cultivation potential and having higher stress tolerance to prevailing stresses (low pH, low moisture) could be a crop of choice for abating malnutrition among hill inhabitants. Proper time of sowing of the crop is between mid-September and mid-December seemingly essential for better grain yield to the tune of 15.0–18.0 q ha−1, and the crop is found suitable to be grown all through the year for higher green biomass (12.6–38.4 q ha−1). Enhanced exudation of low-molecular-weight organic acids (LMWOA) like oxalic acid by buckwheat increased the solubilization of fixed forms of free phosphorus (P) to the extent of 35.0 to 50.0 micro gram per plant in ideal acid soil of the region (P) in acid soil. In addition, relatively increased resilience to moisture stress with improved stress physiological attributes adds more potentiality for enhancing cropping intensity of hill slopes of EHR. Few genotypes namely IC377275 (18.97q ha−1), IC26591 (17.1 qt ha−1), IC14890 (16.32q ha−1), and Himapriya (15.27q ha−1) are emerging as high-yielding types for productive cultivation in acid soils. Studies on the combined effects of acid soil and moisture stress would aid in novel crop improvement of buckwheat in EHR.

Soil moisture stress in lentil (Lens culinaris L.) cultivated in rice (Oryza sativa L.) fallows of Tripura (50 m above msl), India, is one of the issues related to low productivity. Effects of foliar feeding of lentil with urea and potassium chloride KCI @ 2% each, singly or in combination either at 50% flowering, 50% podding or both at 50% flowering + 50% pod formation stages under moisture stress condition were investigated. The key physiological parameters viz. chlorophyll a, chlorophyll b, total chlorophyll content, leaf relative water content (LRWC), excised leaf water loss (ELWL) and yield attributes of lentil were measured. There were significant plessthan0.05) increases in chlorophyll a, chlorophyll b and total chlorophyll content at 50% flowering and 50% pod formation stage in plants treated either with 2% KCl alone or in combination with 2% urea as compared to those under control and 2% urea alone. Further, LRWC and ELWL were the highest (83%) and lowest (0.7%) under combined application of two agro chemicals, respectively. Significant (plessthan 0.05) increases in plant height, number of branches per plant, numbers of pods per plant and biomass as well as seed yield were also observed with combined foliar application of agrochemicals in comparison to those under control. The highest LRWC and lowest ELWL were recorded in case of foliar spray at 50% flowering + 50% pod formation as compared to either 50% flowering or 50% pod formation stage alone. Foliar application of both agro-chemicals mitigates the terminal moisture stresses especially in underutilized rice-fallow lands for successful cultivation of rabi crops like lentil.

Rice straw is globally abundant agricultural by-product and faces significant waste management challenges. Insect bioconversion offers a promising valorisation strategy, transforming waste into valuable protein for animal feed applications. This study investigated the effects of four different rice straw pre-treatment methods—chemical (C), biological (B), biochemical (BC), and a control (N)—on substrate nutritional composition, black soldier fly, BSF (Hermetia illucens) larval growth, and the resulting larval nutritional profile employing a completely randomized. Derived results demonstrate that biochemical pre-treatment significantly enhanced crude protein (9.11 ± 0.32%) and crude lipid (2.08 ± 0.02%) content in the treated straw (p ≤ 0.05). While the control (N) exhibited higher lignin and hemicellulose levels, BC maximized cellulose content (44.4 ± 0.26%). Larvae reared on BC-treated straw demonstrated superior growth performance, exhibiting significantly higher crude protein (43.60 ± 0.27%) and lipid (9.75 ± 0.03%) levels (p ≤ 0.05), along with improved survival, waste reduction index, and feed conversion efficiency. These findings highlight the efficacy of biochemical pre-treatment in enhancing rice straw as a substrate for BSF larval production, offering a sustainable solution for both agricultural waste management and high-quality protein production for aquatic animal feed.