The Effect of Nitrogen Rates on the Physiological Characteristics of Some Vegetable Crops

Samarkand State University, Samarkand, Uzbekistan

^* Corresponding author: moxigul_usmonova@samdu.uz

Abstract

As a key macronutrient, nitrogen significantly affects plant physiological processes, growth and yield. Physiological performance and yield potential of tomato and sweet pepper are markedly influenced by nitrogen rates. The effect of nitric fertilization on physiological property of varieties and hybrids of tomato (Solanum lycopersicum L.) and sweet pepper (Capsicum annuum L.) grown in the field and green house conditions is studied under Uzbekistan. A field experiment using sweet pepper (Capsicum annuum L.) was conducted in 2025 at the Oqtepa-Beshariq farm (Bulung‘ur district, Samarkand region, Uzbekistan). In Uzbekistan, the stability in vegetable production has become a matter of national concern since vegetable crops, particularly tomatoes and sweet peppers, are the backbone to global food security and export. Five rates of N were compared to identify the optimum physiological trade-off point between chlorophyll synthesis, transpiration and vegetative production. The results indicated that 150 kg N ha^-1 increased the plant height and pigment content significantly while, increased nitrogen induced physiological stress and reduced pigment.