Interactions between fungicide, plant growth regulator, nitrogen fertiliser applications, foliar disease and yield of winter barley

Abstract

SUMMARYLeaf size and foliar disease in winter barley increased with increasing total amounts of nitrogen applied to the crop: flag leaf areas increased at an average of 10% per 35 kg N ha‐1 Nitrogen top dressing applied in mid‐March (G.S. 31) resulted in larger leaves, more foliar disease, more straw, delayed ear emergence, fewer grains ear‐1 and less grain yield than nitrogen applied in mid‐April (G.S. 31). Application of chlormequat at G.S. 30 gave a variable response, but overall it increased fertile stems m‐2 and crop yield and decreased crop height but had no significant effect on straw yield. Fungicide treatments suppressed foliar disease and improved yield. Yield responses were greater when plant growth regulator and mid‐March nitrogen had been applied at sites where more disease prevailed than with April‐applied nitrogen. In one of the field experiments, on cv. Sonja, delaying the main nitrogen application until April, without fungicide treatment, gave a similar yield to that provided by nitrogen in March with two or three fungicide sprays.

Fungicide and nitrogen applications in relation to the improvement of disease control and yield in winter barley

“…Experiments on winter barley in south-west England since 1981 (Jordan et ai, 1985;Jordan & Stinchcombe, 1986a, 1986b, 1988, characterized and quantified the effects and interactions of three major input variables in winter barley production. They also showed that postponing the main N dressing until mid-April can reduce both the risk from fungal diseases and the need for fungicide sprays to maintain yield and quality.…”

Agronomic response of six-row barley cultivars to supplemental fertilization and late-season fungicide treatments

“…found positive yield responses of barley cultivars to Tilt application independent of resistance or susceptibility to net blotch. Johnston and Macleod (1987) found Jordan and Stinchcombe (1986) reported an increase. Floret fertility may be affected by treatments that affect assimilation (Fischer and Stockman 1980).…”

“…En outre, ses effets sur la hauteur de la paille, sur le nombre de talles viables de la hauteur de la paille, du nombre de talles viables par mbtre carre et de grains par 6pi, mais la teneur en protdine du grain n'a 6t6 augment6e qu'une seule ann6e (1988 Jordan and Stinchcombe (1986) and Zebarth and Sheard (1991) found that increased Nfertilization increased the severity of foliar diseases because of lush vegetative growth.…”

Effects of winter barley cultivar mixtures on lodging

“…Lodging of cereal crops may be reduced by various means such as plant growth regulators or by breeding. In winter barley, however, effects of growth regulators depend to a great extent on favourable environmental conditions (Jordan & Stinchcombe, 1986). Adding a resistant component to a lodging-susceptible cultivar might be an inexpensive and more reliable way to reduce lodging.…”