Maize evapotranspiration and water-use efficiency in response to row spacing

Abstract

Reduced row spacing has shown to increase maize (Zea mays L.) yield; however there are conflicting results on whether narrow rows increases maize crop evapotranspiration and/or water use efficiency. This work analyzes the response of maize yield, crop evapotranspiration (ET) and water use efficiency to reduced row spacing under different water and N regimes. Maize crops were grown at Balcarce, Argentina, during two seasons. Treatments included two water regimes (rain-fed and irrigated), two rows spacing (35 and 70 cm) and two rates of N (i.e., 180 kg N ha−1 or nonfertilized). Soil water content was measured through the growing seasons using a neutron probe, grain yield and shoot dry matter were determined at physiological maturity. Grain yield response to narrow rows ranged from 0 to 23%; it was higher for water limited (i.e., rain-fed crops) and/or N deficient crops (i.e., nonfertilized crops) and lower for crops with high N fertilization and irrigation. Narrow rows consistently increased (8%) crop ET during the initial stages of crop growth; and N fertilization did not influence ET response to reduced row spacing during this period. Initial differences in ET between row spacing treatments were diluted as the season progressed, and seasonal crop ET was not influenced by row spacing. Reduced row spacing increased water use efficiency for grain production up to 17%; increments were larger in N deficient crops and/or with water limitations but were negligible in N fertilized and irrigated crops.