Evaluation of tillage effect on maize production using a modified least limiting water range approach

Abstract

AbstractThe objective of this research was to identify the mechanism of how tillage methods affect maize (Zea mays L.) production using a modified least limiting water range (LLWR) method. The LLWR is the range of soil water content within which the water and O2 are sufficiently supplied, the root growth is not restricted by penetration resistance, the root is fully contacted with the soil, and the crop is steadily hold by the soil. A 5‐yr field experiment was conducted with five treatments: no tillage, rotary tillage, conventional plow, subsoiling, and soil compaction after rotary tillage. Soil bulk density, water content, and penetration resistance were monitored annually. The soil water retention curve and penetration resistance curve were measured to determine the LLWR. Excessive soil looseness was included in the determination of the LLWR. The maize yield would be high and stable when the tillage treatment was under an optimal bulk density range with the highest LLWR. At this experimental site, the maize yield was high and stable with the relative yield of 98.3–100% when the bulk density was within 1.43–1.51 g cm–3 and the LLWR reached 0.07 g g–1 in the tillage treatments. The yield fluctuated with the relative yield of 86.3–100% when the LLWR was less than 0.035 g g–1 and the bulk density was not in the optimal range. The optimal bulk density range with high LLWR was a useful parameter for the evaluation of tillage methods.