Effect of exogenous application of Boron and Zinc with or without added urea on the yield and nutrient assimilation of cotton

Abstract

A two year’s field trial was conducted to investigate the impact of foliar by applied boron (B) and zinc (Zn) with or without added urea on plant nutrient content and seed cotton yield. The experimental site was situated at Central cotton Research Institute, Multan during the years 2008 and 2009. Treatments, laid out in RCBD with four replications, consisted of untreated check and foliar sprays of B0.1%, Zn0.2%, B0.1%+Zn0.2%, B0.1%+urea2%, Zn0.2%+urea2% & B0.1%+Zn0.2%+urea2% . In foliar application the whole quantity was split into three equal doses and applied at day 30, 45 and 60 after planting. The basal dose of fertilizers was 150kg N, 50kg P2O5 and 50kg K2O ha-1 in the form of urea, TSP and SOP, respectively. The whole quantity of P, K and 1/3rd  N fertilizers was applied at planting whereas the remaining N was applied at first flower and peak flowering phases. cotton cv. CIM-534 was used as test crop. Results revealed that plant nutrient (N, B, Zn) content, fruit production per unit area, dry biomass production, boll number plant-1, boll weight and seed cotton yield increased while fruit shedding decreased with all the treatments over control. The values of N, B, and Zn in leaves ranged from 40.2-55.3, 50.0-58.6 µg g-1 at 24 and 40.5-58.4, 50.2-65.5 µg g-1 at 72 hours, respectively. However, the maximum effects were observed where B, Zn and urea were applied in combined form. Application of B0.1%+Zn0.2%+urea2% increased fruiting positions by 18.4%, intact fruit by 81.4%, boll number plant-1 by 27.8%, boll weight by 6.9% and seed cotton yield by 27.8% over control plots. Thus addition of urea @ 2% in nutrient spray solution may be added to improve nutrient assimilation and seed cotton yield.