Links between yield, protein and responses to nitrogen

Four years of barley field trials in northern NSW have produced some answers regarding the links between yield, protein and likelihood of a response to nitrogen.

Schooner responded to fertiliser nitrogen in 17 out of the 31 trials conducted from 1987 to 1990.

Analysis of this mountain of data showed that grain protein levels in the zero fertiliser treatments were a good guide to the likelihood of a response to nitrogen. Below 11 per cent protein, a yield boost was very likely. But when protein levels fell below 10 per cent there were usually large yield losses from inadequate nitrogen.

The findings indicate that with consistent production of malting barley yield is being lost due to nitrogen deficiency.

Semi-dwarf varieties

Semi-dwarf lines, based on a mutant gene, now dominate European barleys. The gene is associated with stiff straw, high tillering capacity and good yield potential. The variety Triumph, which has excellent malting quality, has the mutant gene and has been widely used as a parent. Its disadvantage is relatively late maturity, as found in Onslow (WA), Franklin (Tasmania), Ulandra (NSW) and Skiff (SA), which have been recommended only for longer season, high rainfall areas of southern Australia. However, in northern and central western NSW, Skiff has proven of wider adaptability, and has found a place as a high-yielding feed grain variety. It has done particularly well in the northern areas following evaluation.

Researchers say that provided earlier maturity can be combined with the semi-dwarf trait, this type of barley with its excellent agronomic characteristics, grain holding ability, yield and quality potential could become the dominant type for Australian conditions.