Responses by wheat to lupin, soil amelioration and fertilizer treatments in a solodised solonetz soil

Abstract

Disruption of the junction of the A-B horizons of a yellow duplex soil did not affect moisture extraction or grain yield of wheat grown in the Southern Wimmera, and it is unlikely that this zone represents a serious impediment to root growth. However, improving soil fertility, either by growing lupins or by placing nitrogen and phosphorus in the A2 horizon, did increase yields. Following lupins in 1983, wheat yield increased from 4.3 to 55 t/ha in 1984,andfrom 3.1 to3.7 t/ha in 1985. This response was greater than that due to deep placement of nitrogen and phosphorus (0.3 t/ha in 1984,0.4 t/ha in 1985), probably because of improved root growth as a result of less root disease. There were consistent responses to foliar applications of copper and interactions with other treatments; the greatest responses occurred in situations of improved nitrogen nutrition.