Response of maize hybrids under limited irrigation capacities: Yield and yield components

Abstract

Grain yield of maize (Zea mays L.) in the semiarid Texas High Plains (THP) is greatly reduced when irrigation cannot meet peak water requirements. Drought‐tolerant hybrids may mitigate yield losses resulting from water deficits. We examined the effect of irrigation capacity (8.47 and 4.23 mm d–1) and planting rates (74,000 and 95,000 seeds ha–1) during three growing seasons (2016–2018) on grain yield and yield components of three maize hybrids, two of which were considered drought tolerant. Crop water deficits at the low irrigation level usually extended temporally from seventh leaf collar to dough stage. Mean grain yields varied from 5.2 Mg ha–1 under the low irrigation level to 19.9 Mg ha–1 at the high irrigation level. Hybrid did not influence grain yield and aboveground biomass in all 3 yr. Although kernel number and kernel mass were significantly influenced by hybrid across all years, this did not result in grain yield differences because greater kernel mass compensated for reduced kernel number. Harvest index did not significantly differ between conventional and drought‐tolerant hybrids. In 2016, grain yield was significantly influenced by plant density only at the low irrigation level, with 44% greater yields at the low plant density. For the patterns and level of water stress observed during these three growing seasons, the three hybrids performed similarly. Besides using hybrids well adapted to the region, mitigation of yield reductions under limited irrigation capacities in the THP can be achieved by concentrating irrigation on less land area and optimizing planting rates.

Response of maize hybrids under limited irrigation capacities: Crop water use

“…In addition, these hybrid × irrigation capacity treatment combinations were examined under seeding rates considered to be conservative (74,000 ha −1 ) and high density (95,000 ha −1 ) to evaluate interactions between water stress and plant density. Responses of grain yield, yield components, and water use efficiency to hybrids, imposed irrigation capacities, and plant densities are presented in detail in Schwartz et al (2022).…”

“…The neutron probe used in this study was previously calibrated in 2002 using methods described by Evett and Steiner (1995) with separate equations for the A, Bt, and Btk horizons. Crop evapotranspiration (ET a ) was estimated based on soil water balance evaluations from planting to harvest maturity, defined as attainment of a grain moisture content of approximately 250 g kg −1 , which occurred 8-18 d after black layer (see Schwartz et al, 2022). Soil water balance was obtained by summing the change in stored soil water (0-1.4 m) based on neutron probe measurements, accumulated precipitation, gross irrigation, runoff, and drainage fluxes using the methods presented by Schwartz et al (2020) to calculate drainage and runoff.…”

“…Responses of grain yield, yield components, and water use efficiency to hybrids, imposed irrigation capacities, and plant densities are presented in detail in Schwartz et al. (2022).…”