The relationship between evapotranspiration and growth in the wheat crop

Abstract

In trials conducted in 1961 and 1962 at Wagga in southern New South Wales, to investigate the yield physiology of wheat, the variety Heron was grown under various cultural treatments. This paper deals with the relationship of evapotranspiration to crop growth.

Vegetative growth at a given date in the spring was influenced markedly by time of sowing and fertilizer application, and to a lesser extent by sowing rate. Large differences in vegetative growth caused relatively small differences in evapotranspiration rate when soil moisture was adequate. An increase in total dry weight of 100 g/m² in early October was associated with an increase in cumulative evapotranspiration up to that time of about 0.50 in.

It was concluded that although a reduced fertilizer application and reduced sowing rate (below 3b lb seed per acre) permitted higher soil moisture levels at flowering, this necessarily involved a considerable reduction in total dry weight at flowering. With delayed time of sowing, the post-flowering moisture status of the crop can be expected to deteriorate, primarily because of delayed flowering date.