Full Length Research Paper

Cumulative effects of white clover residues on the changes in soil properties, nutrient uptake, growth and yield of maize crop in the sub-humid hilly region of Azad Jammu and Kashmir, Pakistan

M. Kaleem Abbasi* Azhar Mushtaq and Majid Mahmood Tahir

Department of Soil and Environmental Sciences, University of Azad Jammu and Kashmir, Faculty of Agriculture, Rawalakot Azad Jammu and Kashmir Pakistan.

*Corresponding author. E-mail: kaleemabbasi@yahoo.com. Tel: +92 (0) 58710 42688. Fax: +92 (0) 58710 42826.

Accepted 6 May, 2009

White clover grows naturally all over the Himalayan regions including the hilly areas of the state of Azad Jammu and Kashmir (AJK), Pakistan. This study was conducted to investigate the effects of white clover residues alone or in combination with phosphorus (P) fertilizer on maize (Zea mays L.) yield, nutrient uptake and soil properties in the hilly area of AJK. Local ecotype of white clover was established over three years in the research farm and thereafter maize was grown in the same field. The treatments were: T₁ = control without amendments; T₂ = white clover; T₃ = white clover + P₂O₅ at the rate of 50 kg ha^-1, and T₄ = white clover + P₂O₅ at the rate of 100 kg ha^–1. Results indicated that white clover residues alone or in combination with P significantly increased average plant height, dry matter yield, 1000–grain weight and grain yield. Maize dry matter yield in the control plots was 4150 kg ha^-1 which increased significantly to 8697, 9271 and 9879 kg ha^-1 in T₂, T₃ and T₄, respectively. Similarly, the grain yield in T₂, T₃ and T₄ was 5236, 6232, 8696 kg ha^-1 as compared to 3400 kg ha^-1 in the control plots. Addition of white clover residues and P fertilizer reduced the number of days required for tasseling and silking by 4–13 days over control. Residues also increased the NPK concentration in plant shoot causing significantly higher total uptake of NPK in maize. Averaged across treatments, the uptake of NPK by maize was 31, 8 and 53 kg ha^–1 as compared to 9.8, 1.2 and 12.2 kg ha^–1 in the control treatment. The residual effects of white clover on soil properties indicated a significant increase in saturation percentage (17–23%) and electrical conductivity (10–20%) whereas pH decreased by 23 units. Furthermore, organic carbon (C), total N, available P, K and CEC were higher in plots that received white clover alone or in combination with P than the control. White clover residues seemed to be valuable N source for biomass and grain production in hill farming system and their continuous use as soil amendment would enhance crop productivity and improve crop quality and soil fertility.

Key words: N uptake, pasture, plant residues, residual effects, soil nutrients.