NUTRIENT BALANCES AS AFFECTED BY INTEGRATED NUTRIENT AND CROP RESIDUE MANAGEMENT IN COTTON-WHEAT SYSTEM IN ARIDISOLS. I. NITROGEN

Abstract

A five-year cotton–wheat rotation field experiment was conducted on two alkaline-calcareous soils, i.e., Awagat (coarse loamy) and Shahpur (fine silty), to investigate the impact of integrated nutrient and crop residue management on soil and crop productivity. Apparent nitrogen (N) balances were developed. Minimum five-year mean yield (Mg ha⁻¹), obtained with Farmers’ Fertilizer Use (FFU) treatment was: cotton – Awagat, 2.19; Shahpur, 2.45; wheat – Awagat, 3.03; Shahpur, 3.94. With Balance Nutrient Management (BNM), yields increased (P ≤ 0.05) for cotton, 24% in Awagat and 18% in Shahpur soil; and wheat, 37% in Awagat and 24% in Shahpur soil. Maximum crop yields were obtained with Integrated Nutrient Management (INM), i.e., 3–5% higher than with BNM. Crop residue recycling increased the yields further, cotton by 2−7% and wheat by 2–10%. All nutrient management treatments, except for FFU without crop residue recycling, resulted in positive apparent N balances. INM improved SOM and NO₃-N, contents.

Keywords:

• cotton-wheat rotation
• crop productivity
• nutrient management
• crop residue
• N uptake
• apparent N balances
• soil organic matter

ACKNOWLEDGMENTS

Financial support for this multi-year field-cum-laboratory investigation was provided by the Ministry of Science & Technology, Government of Pakistan, Islamabad, through the Pak-Kazakh Joint Research Fund Project. The authors are indebted to the Central Cotton Research Institute, Multan and the Pak-German Institute for Cooperative Agriculture, Multan for invaluable support in this challenging field research endeavor. We are also grateful to M. Inayat Khan and M. Asif Ghumman for guidance and support in experimental design and the statistical work and to M. Tauseef Tabassum and Zulfqar Ali for assistance in analytical work.