CONSERVATION TILLAGE PRACTICES OPTIMIZES ROOT DISTRIBUTION AND STRAWYIELD OF SPRING WHEAT AND FIELD PEA IN DRY AREAS

Abstract

The objective of this study was to evaluate the effect of conventional tillage with straw removed (T), no tillage with straw removed (NT), no tillage with straw retained on the soil surface (NTS) and conventional tillage with straw incorporated (TS) on soil moisture, root growth and straw yield under rain-fed conditions. Findings of this research show that NTS and to a lesser extent, TS decreased soil bulk density in the 0-10 cm soil depth by approximately 3.35% and 2.75% compared to T and NT in spring wheat and field pea plots respectively. No tillage with straw retained (NTS) had greater soil moisture content (0-30 cm) at jointing, anthesis and milking stages compared with NT and T treatments with average 18.57% and 29.67% increase (P < 0.05) in spring wheat and field pea respectively. Compared with T and NT, root length, root surface area, root diameter and root volume at 0-50 cm soil depth under straw treated soils, especially with no tillage were significantly increased. Root length, surface area and root diameter in the 0-80 cm differed among the treatments in the order of NTS > TS > NT > T at all the sampling stages in both crops. No tillage with straw retention had the greatest straw yield of 4897 kg ha-1 in spring wheat and 2759 kg ha-1 in field pea, representing a significant increase of 20.61% and 22.74% compared to NT and T respectively. These results suggest that NTS could enhance spring wheat and field pea yield and water uptake via stimulating root growth, and therefore a practical way to improve crop productivity.