Waterlogging as a Limitation to Wheat Yield in an Irrigated Clay Soil
Wheat production currently occupies a small proportion of the total irrigated area of south-east Australia. At average yield levels of about 2.6 t ha-1 it is not an economic alternative to rice or intensive vegetable crops also grown in the area. However as the availability of irrigation water becomes more constrained, wheat, at yield levels near those obtained under the best soil and water management conditions (about 8 t ha-1), would be economically competitive. This possibility, together with the greater yield per unit of water applied, compared with rice, indicates that increasing areas of wheat may be sown. However it is not yet completely understood why average yields of wheat are low. Circumstantial evidence suggests that it is associated with the poor internal drainage properties of the irrigated clay soils. This paper describes an experiment in which some of the processes occurring within the root zone were measured during an irrigation cycle. Having quantified root zone processes, it is intended to include them in a wheat growth and yield model that can be used as an aid in making decisions about optimum soil amelioration, water management and nutrient management of irrigated wheat.
KeywordsClay Porosity Maize Respiration Aeration
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