Planting date and plant density effects on maize growth, yield and water use efficiency

Abstract

Weather conditions in the southwestern United States are variable and influence crop growing periods with late spring and early fall frosts which significantly impact cropping seasons. With the development of new maize hybrids, grain yield, evapotranspiration, and water use efficiency can be substantially impacted by planting density and planting date. Thus, the optimum plant density and planting date for maximum grain yield must be determined for local conditions. Field experiments were conducted at NMSU Agricultural Science Center in Farmington to evaluate six plant densities (54,700; 64,600; 74,600, 88,000; 101,700; and 120,100 pph) under seven planting dates (from April 23 to June 5 in 2019 and from April 21 to June 10 in 2020) to determine the planting window and the optimum density. Plots were sprinkler irrigated and crop management was similar across all planting dates during the two growing seasons. The results showed that crop height and leaf area index varied with plant density and planting date. Grain yield also varied with plant density and planting date. The highest grain yield (16.8 Mg ha−1) was observed under the density 101,700 pph which showed statistically similar yield as the density 88,000 pph and the first planting trended to provide the best grain yield in 2019. In 2020, the highest grain yield (17Mg ha−1) was obtained under the density 88,000 pph on May 18 planting date. Plant density 88,000 pph was revealed as the optimum density that maximized grain yield and WUE and maize planting after May 25 is not recommended.