Influence of Tillage on Phenology and Carbohydrate Metabolism of Spring Wheat1

Abstract

AbstractNo‐tillage systems help reduce soil erosion, yet crop growth is often adversely affected by the presence of surface residue. The specific effects of no‐tillage systems on phenological events of spring wheat (Triticum aestivumL.) have been poorly characterized. A field study was conducted on a Palouse silt loam (fine‐silty, mixed, mesic Pachic Ultic Haploxeroll) during 1983 and 1984 to examine the growth and development of four spring wheat cultivars grown under conventional (fall plow and spring disk) and no‐tillage (direct drilling) tillage systems. Throughout the two growing seasons, leaf and tiller production, tiller abortion, and soil moisture were monitored while leaf area, leaf weight, and stem weight were determined at weekly intervals in 1983. The length of the second leaf on the main stem, rate of leaf production, and rate of tiller production were reduced in plants grown in no‐tillage compared with conventional tillage. Except for the cultivar ‘Waverly’, tiller production was reduced by no‐tillage but tiller abortion was not. More soil water was available throughout the season in the no‐tillage plots, yet the plants grown in no‐tillage tended to be smaller than conventionally grown plants. Total nonstructural carbohydrates in the lower stem‐crown area at 12 days after anthesis were not affected by tillage treatment, and all cultivars had used most of this stored carbohydrate by physiological maturity. Overall, these results indicated that stresses that occur early in seedling development under no‐tillage reduced early growth and the plants were unable to overcome these effects prior to maturity. However, cultivars differed in tolerance to these early stresses. Thus, it should be possible to develop spring wheat cultivars for growth under no‐tillage.