Tillage and Nitrogen Fertilization Impact on Irrigated Corn Yields, and Soil Chemical and Physical Properties Under Semiarid Climate.

Abstract

This study evaluated the effects of tillage (deep tillage (DT), conventional tillage (CT), minimum tillage (MT) and no-till (NT)), and nitrogen (N) rates (0 (N0), 200 (N200), 250 (N250), and 300 (N300) kg ha -1 ) on: i) corn growth and yields, ii) some soil chemical properties (total soil carbon, nitrogen, and available nutrient stocks), and iii) selected soil physical properties (bulk density, total porosity, and infiltration) under semiarid climate. Total carbon (Corg), total nitrogen (TN), nitrate, available phosphorus (AP), exchangeable potassium (K), bulk density (b), penetration resistance (PR) and soil infiltration rates were measured. No-till had significantly higher Corg (9%) but lower TN (5%) as compared to CT. Deep tillage decreased b (2 to 5%) and PR (35 to 60%) compared to other tillage practices. The highest level of N had higher Corg (20%), TN (30%) and nitrate (35%) compared to the control treatment. The Highest N rate under DT has higher harvest index than those of CT, MT, and NT treatments. The nitrogen rate of 240 kg ha -1 produced near maximum yields (~90%) in DT and CT than the 260 kg ha -1 N -MT treatment and the 270 kg ha -1 N-NT treatment.