Evaluation of Drip-Irrigated Cotton Grown under Different Plant Population Densities and Two Irrigation Regimes

Abstract

Modification of plant population density and irrigation regime may impact seed cotton and lint yield, fiber quality, photosynthesis, and nitrogen uptake, especially in areas with severe water shortages and limited water resources. Furthermore, it reduces seeds and other agricultural practices costs without sacrificing yield. Field experiments examining the impact of plant population and irrigation regime on cotton growth, cotton yield parameters, fiber quality, leaf area, and chlorophyll content of cotton leaves were conducted in the city of Aleppo, northern Syria, in 2004 and 2005. Plant populations of 74,000, 57,000, 48,000, 41,000, and 33,500 plants ha−1 and two drip irrigation regimes [one planting row/one irrigation line (one/one) and two planting rows/one irrigation line (two/one)] were tested. Cotton was planted in April 2004 and 2005 at the Agricultural Research Center in northern Syria on a Chromoxerertic Rhodoxeralf soil. Cotton was irrigated when soil moisture in the specified active root depth was 80% of the field capacity as indicated by the neutron probe. Before all plots were hand-picked each year, a 20-lint sample was collected per plot and sent to the Cotton Research Administration Laboratory for fiber quality analysis. Seed cotton yields were lowest with populations of 33,500 plants ha−1 compared to the other tested population densities. However, the other plant densities did not much influence seed cotton yield, fiber quality, leaf area, and leaf chlorophyll content. Water savings for different plant densities grown under the one/one irrigation regime ranged between 11.2 and 38.3% of irrigation water relative to two/one irrigation regime. Reducing population densities up to 41,000 plants ha−1 and adapting a one/one irrigation regime appear to be viable cost-saving options.