TITLE:
Plant Nutrient Status during Boll Development and Seed Cotton Yield as Affected by Foliar Application of Different Sources of Potassium
AUTHORS:
Nirmal Kaur Sekhon, Chandra Bhushan Singh
KEYWORDS:
Cotton; Foliar Fertilizers; Boll Development; Potassium; Nitrogen
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.7,
July
11,
2013
ABSTRACT: Bt cotton
hybrids require large supply of metabolites to support their greater boll load
and commonly suffer from premature leaf senescence. A field
experiment was conducted to study the nutritional status of Bt cotton leaves
during boll development stage and to evaluate the most profitable source of
foliar fertilizers. Treatments included basal application of 0 and 60 kg·K2O·ha-1 as muriate of potash (MOP) in main plots and foliar spray treatments
viz: 4 & 6 sprays of 2% potassium nitrate (Multi-K, 13-00-45), 4 & 6 sprays of NPK Blend (Polyfed, 19-19-19), 4 sprays of MOP, 4
sprays of MOP + urea (to supply same amount of N & K as in potassium
nitrate) and unsprayed control in sub
plots. The results revealed that only N and K contents of premature senesced
leaves were below the sufficiency range for cotton sufficient
levels of P, Fe, Mn, Zn and Cu were observed. Though the concentrations of N
and K in both the petiole and leaf blade initially improved with foliar spray,
N content declined below the unsprayed control at later stages. Basal
application of MOP increased seed cotton yield by 19%. Four foliar sprays of
KNO3, NPK, MOP and MOP + urea recorded yield increase in seed cotton
yield of 22.8%, 22.4%, 18.5% and 24.5%, respectively
over unsprayed control. Six sprays of KNO3 and NPK had no yield
advantage over four sprays and rather proved economically less viable.