Soil type influences the relative yields of different cereals and crop legumes in the Western Australian wheatbelt

Abstract

Crop choice depends on the relative yields of different species, and will vary according to soil type and seasonal conditions. Crop legumes are a relatively new component of agriculture in southern Australia, especially on the drier fringe of the agricultural areas. In this study wheat, barley, field peas and narrow-leafed lupin were compared at Merredin, Western Australia (mean annual rainfall 310 mm) from 1984 to 1986 on a red brown earth, a solonised brown soil, a solodic soil and, in 1984 and 1985, on an acid earthy sand. Oats, cereal rye and triticale were included in 1984, and chickpeas in 1984 and 1986.

Highest mean seed yields were produced on the red brown earth and solonised brown soil, although the red brown earth produced very low yields in a dry season. Lowest yields were produced on the earthy sand. Triticale, oats and cereal rye yielded less seed than wheat or barley on all soils except the earthy sand where triticale yielded more than wheat. Legumes yielded less seed than cereals, although the yield for peas was close to that for wheat on the red brown earth. Peas yielded more than lupins or chickpeas on all soils. Lupin yield was closest to pea yield on the solodic soil and earthy sand. A separate series of experiments comparing peas and lupins in different seasonal conditions but on similar soils showed that lupins yielded more than peas when growing season rainfall was high. Peas are the most suitable crop legume for the Merredin area on all fine-textured soils. Lupins remain the choice on coarse-textured soils until pea stubbles can be managed to minimise erosion. In wetter areas lupins are a better choice on coarse-textured soils.