Effects of fine-particle amendments on the soil moisture characteristics of a gravelly sandy loam and on crop yields

Abstract

SummaryPulverized fuel ash and fiuidized combustor ash were used to modify the availablewater capacity and moisture characteristics of a gravelly sandy loam soil in a study of the effects of fine-particle amendments on crop yield. Intimate incorporation of the ashes into the top-soil at rates of up to 502 t/ha increased the available water retained in the surface 0·3 m of soil by 40–80 %. The increase was mainly water held at potentials of between –0·05 bar and – 1 bar.Two sugar-beet crops followed by broad beans, salad onions and cabbage were grown in the amended soil. With the highest rate of ash addition yield of the onions was increased by over 30% and of the cabbages by 14%. No improvement in sugar-beet or broad-bean yields resulted from the treatment. Poor growth of the second sugar-beet crop was attributed to a reduced aeration effect but it is suggested that the failure of the increased available water to improve yield consistently in this and a previous experiment was in part caused by rapid evaporative losses from the amended soil.