Amelioration of Cotton Leaf Reddening with Boron and Zinc Application through Balanced Nutrient Management Practices

A field experiment was conducted to study the effect of nutrient management on growth, yield characters and leaf reddening in cotton (Gossypium hirsutum L.). Cotton variety Haridost wasstudied under 4 NPK treatments (000 NPK kg ha^-1, 120-0-0 kg N ha^-1, 120-70-0 kg N ha^-1, 120-70-40 kg NPK ha^-1 and 5 secondary and micronutrient (Control, 50, 3, 4 and 1.5 kg ha^-1 Mg, Fe, Zn and B, respectively) treatments. NPK @ 120-70-40 kg ha^-1 resulted maximum plant height, number of green leaves plant^-1, number of opened bolls plant^-1, seed index, and seed cotton yield ha^-1. Red leaves reduced when soil was fertilized with N, P and K @ 120-70-40 kg ha^-1; and plots without application of K (120-70-0 kg ha^-1) and PK (120-0-0 kg N ha^-1) increased number of red leaves. In case of micronutrients, Zn @ 4 kg and B @ 1.5 kg ha^-1 were highly effective to control reddening of leaves, respectively. Interactive effect of NP @ 120-70 kg ha^-1 × Zn @ 4 kg ha^-1 resulted in maximum reduction of red leaves. Regardless the application of N, P or K and their control, reddening of leaves was linearly affected by Zn and B. It is concluded that there was no direct effect of N, P, K, Mg and Fe on the reddening of cotton leaves but B and Zn application decreased number of red leaves. Plant growth improved markedly when essentially needed NPK was applied @ 120-70-40 NPK in combination with Zn and B @ 4 and 1.5 kg ha^-1, respectively.