Neem is known for its medicinal values and is a hardy plant that can grow in a wide variety of environmental conditions. However, productivity is impacted by unfavourable weather conditions due to different geographical locations. The present study was conducted to study the influence of prevailing weather conditions on certain physiological parameters deciding the reproductive ability of neem trees. The study was conducted in two different locations at different agro-climatic regions of Tamil Nadu, India. Gas exchange parameters like photosynthetic rate, stomatal conductance, transpiration rate and leaf temperature and relative water content during pre-flowering, flowering and post-flowering stages were measured and correlated with temperature, relative humidity, precipitation and wind speed observed from the corresponding location. In both locations, the neem trees recorded significantly higher values for these physiological parameters during the pre-flowering and fruiting stages compared to the flowering stage. The trees with higher Diameter and breast height (DBH) showed higher values for gas exchange parameters compared to the trees with lower DBH.

Application of highly sustainable and productive inputs is required to increase food production in order to feed the growing world population while using the same amount of land. Thus, in its very first attempt, the Tamil Nadu Agricultural University (TNAU), Coimbatore, Tamil Nadu, has produced water soluble fertilisers (WSF) named as TNAU-Water Soluble Fertilizers (TNAU-WSF), and it is necessary to optimise on various crops. One of the most essential vegetables in Indian cuisine is the small onion, which has a high demand but a low productivity. The use of TNAU-WSF was initiated to improve small onion crop productivity and quality. Eight treatments were incorporated in a field experiment that was set up using a Randomised Block Design (RBD), including soil test-based applications (STB) of 75%, 100%, and 125% NPK ha-1 as TNAU-WSF, with and without sulphur (S) and TNAU liquid multi micronutrient (TNAU LMM) and the absolute control. With small onion (CO 4), each treatment was replicated three times. Soil test based application at higher nutrient level (125% NPK) recorded higher nutrient availability, plant nutrient content and enhanced bulb quality (crude protein and total sugars) of small onion. The correlation study revealed that treatments with higher nutrient availability had a high impact on nutrient content and bulb quality of small onion.

To achieve sustainability in agricultural crop production, water-soluble fertilizers were produced around the world. With this view, Tamil Nadu Agricultural University, Coimbatore, has produced TNAU-Water Soluble Fertilizers (TNAU-WSF). The field experiment was carried out in the farmer’s field at Devarayapuram, Coimbatore, to assess the effect of newly synthesized TNAU-Water Soluble Fertilizers (TNAU-WSF) on nutrient uptake and nutrient use efficiencies of  small onions. The experiment was conducted in Randomized block design (RBD), which includes eight treatments of different nutrient levels of soil test based application from 125%, 100% and 75% NPK as TNAU-WSF with sulphur and TNAU Multi Micronutrient (TNAU-LMM). The results were obtained as the soil test based application of 125% NPK as TNAU-WSF with sulphur and TNAU-LMM recorded higher nutrient uptake (N, P, K, and micronutrients) and nutrient use efficiencies (agronomic efficiency and apparent nutrient use efficiency) compared to other nutrient levels (100% and 75%).