Soil water and crop water use with crop rotations and cultural practices

Abstract

AbstractLimited and erratic precipitation in arid and semiarid regions can affect soil water storage, water use, and dryland crop performance. Our objective was to examine soil water content, crop yield, and water‐use efficiency (WUE) with crop rotations and cultural practices for 6 yr in the northern Great Plains. Crop rotations were durum wheat (or durum) (Triticum turgidum L.)−durum−canola (Brassica napus L.)−pea (Pisum sativum L.) (DDCP), durum−durum−flax (Linum usitatissimum L.)−pea (DDFP), durum−canola−durum−pea (DCDP), and durum−flax−durum−pea (DFDP). A continuous durum (CD) was also included for comparison. Cultural practices were traditional (a combination of conventional tillage, recommended seeding rate, broadcast N fertilization, and reduced stubble height) and improved (a combination of no‐tillage, increased seeding rate, banded N fertilization, and increased stubble height) practices. Pre‐plant and postharvest soil water contents at the 0‐ to 122‐cm depth were 19−39 mm lower with DDFP than other crop rotations. Pre‐plant soil water was 21−39 mm greater in the improved than the traditional cultural practice in 3 out of 6 yr. Annualized grain yield was 207−370 kg ha−1 lower with DDFP than CD and DCDP. Overall water use and WUE (yield/water use) for the rotation system were not affected by treatments, but varied for each crop as the growing season precipitation (GSP) increased. Pre‐plant and postharvest soil water, water use, grain yield, and WUE for each crop in the rotation varied with treatments and years. Alternate‐year rotations and CD can enhance dryland soil water storage and crop yield compared to stacked rotations.