Clovers in Canterbury pastures

Abstract

Cropping and cultivation under warm and moist conditions leads to a rapid depletion of the organic matter in the soil. In the cropping-areas of Canterbury the depletion of organic matter is of major importance, often responsible for the poor establishment of pastures and the low carrying-capacity of them as well as low yields of crops. Nitrogen is made available in the soil for grass-growth from at least two important sources : (a) the organic matter-this does not increase the nitrogen-content of the soil unless it be from leguminous crops ; and (b) direct from growing legumes. The available nitrogen encourages vigorous grass-growth, and this when fed off adds to the organic matter in the soil, and the fertility of the soil is built up. Calculations of the amount of nitrogen added to the soil by clovers in pastures have been made, and the amount varies with the clover and the soil conditions. There is naturally a limit to the improvement that can be made in the fertility by these means, but on some of the cropping lands of Canterbury that limit is worth aiming at. The general benefits of clovers in pastures are well recognized, and the majority of the mixtures sown contain clovers; but how many on the cropping lands of Canterbury are satisfied with the amount of clover that comes from the sowings, particularly in the first few years in the life of a pasture ?