The influence of soil heterogeneity on the growth and yield of successive crops

Abstract

1. The interaction of physical conditions of the soil and the establishment of plant together with its subsequent growth and yield have been studied for wheat and swedes on a variable piece of land, maintained as a uniformity trial.2. Ploughing draught was taken as a criterion of the physical condition of the soil and various simple measurements on the crop were made from time to time during growth.3. The establishment of wheat showed substantial negative correlations with ploughing draught but the correlations between ploughing draught and the performance of the plant diminished as growth progressed. This was shown to be the result of the overwhelming importance of the spacing factor operating beneficially on plots where the plant was abnormally poor. The effect of this factor is traced step by step.4. Swedes differing from wheat in almost every detail of cultivation and growth, cycle showed no correlation between soil conditions and germination or between the various growth stages and physical soil conditions. The highest significant correlation was between the number of roots per plot after singling and ploughing draught and an explanation of this is given.5. There was a significant but only moderate correlation between the yields of the two crops.