Interpretation of site-treatment effects on growth and N uptake of winter barley in relation to quality, particularly %N in barley for malting

Abstract

Measurements were made of crop and ear dry matter production and of the uptake of nitrogen and its distribution to the ear in winter barley crops grown with no nitrogen fertiliser or with standard amounts at sites in England and Northern Ireland between 1988 and 1990 in order to develop a better understanding of the site and seasonal variation in the nitrogen percentages in grain for malting.

Crops without nitrogen fertiliser were grown as a guide to the background levels of N available to the crop from non-fertiliser sources in the soil. Large differences in grain yield occurred between sites and years in both these and standardly-fertilised crops. Responses to applied nitrogen were greater where the yields of unfertilised crops were small. Differences in yield were largely attributable to differences in numbers of grain m2 which resulted from differences in the numbers of ears per m2. Differences also occurred between sites and seasons in the nitrogen percentages of the harvested grain, but the responses to applied N were much smaller than for yield.

Large differences occurred in post-anthesis dry matter growth, both in the ears and the whole crop, and in nitrogen uptake. These did not explain the observed large site and season differences in the nitrogen concentrations of grain, indicating that the latter was influenced more by pre-anthesis growth and nitrogen uptake. There was evidence that N and dry matter accumulation are closely coupled in developing ears of barley when nitrogen supplies are not excessive.

The results obtained in this project were re-analysed in a later project, which is reported as Project Report No 119.