EFFECTS OF DIFFERENT CROPPING SYSTEMS AND OF A SOIL CONDITIONER (VAMA) ON SOME SOIL PHYSICAL PROPERTIES AND ON GROWTH OF TOMATOES

Abstract

Soil physical condition resulting from different cropping systems was examined on a number of New Brunswick soils and compared with that of the adjoining soils which had been under continuous grass.Continuous cropping to potatoes reduced the percentage of water-stable aggregates and porosity. Other effects of continuous cultivation were a reduction in soil organic matter content, available water capacity and cation exchange capacity.VAMA (soil conditioner) increased the percentage of water-stable aggregates and the porosity of the cultivated soils. On the continuous-grass soils these properties were not affected. Other effects of VAMA were an increase in cation exchange capacity and a reduction in available water capacity on all soils.Yields of tomatoes in the greenhouse were lower on the soils which had been cropped continuously to potatoes than on the corresponding soils which had been under continuous grass. VAMA increased yields of tomatoes on the continuous-potato soils. The increase in yield due to VAMA was directly related to increase in percentage of water-stable aggregates and total pore space.