Response of New Cotton Variety (Rassafa) to Nitrogen Fertilizer and Partial Rootzone Drying Drip Irrigation

Abstract

Introduction: Due to the water shortage and dry Mediterranean condition, determination of water and nitrogen (N) fertilizer requirements is a major challenge for crop production and environment protection. A field experiment was carried out for two consecutive years (2014 and 2015) to evaluate the response of a new cotton variety (cv. Rassafa) to N-fertilizer and drip irrigation. Explanation: Treatments consisted of five different N-rates (0, 50, 100, 150, and 200 kg N ha-1), and three irrigation modes: full irrigation (FI), fixed partial rootzone drying irrigation (FPRD80), and alternate partial rootzone drying irrigation (APRD80). They received 100, 80, and 80% of the seasonal water use, respectively. Cotton was irrigated when soil moisture in the specified active root depth was 80% of the field capacity as designated by the neutron probe. Results: Results indicated that seed cotton yield (SCY), dry matter (DM), and water productivity (WP) could be optimized at an average N-rate of 140 kg N ha-1, for the tested cotton cultivar, whatever the irrigation mode used. In contrast to APRD80 mode, the findings showed that both FI and FPRD80 modes exhibited a consistence over years, but with an obvious preference of FI in SCY, DM, and WP.