The value of Indian mustard in cereal and legume crop sequences in northwest NSW

Abstract

Mustard is an annual oil seed crop that offers farmers greater flexibility compared to oil producing trees.This study examined the economic benefits of growing mustard in north-western NSW, where production is currently limited. The impact of mustard in crop sequences with wheat and chickpeas; the two most important grain crops in this region, was assessed. Yield and market quality of all three crops was examined and the economic consequences for biodiesel production and the manufacture of other industrial products determined. The Wheat-Chickpea-Wheat sequence increased wheat yield by 12.6% and the Wheat-Chickpea-Chickpea sequence increased chickpea grain protein percentage by 9.9%. The wheat yield in the Wheat-Mustard-Wheat-Wheat sequence was 10% higher than continuous wheat, although this sequence produced 5% lower grain protein. High mustard grain yield and high grain protein concentration were observed in the Wheat-Chickpea-Chickpea-Mustard crop sequence compared to continuous mustard. However, the highest seed oil yield was produced in the continuous mustard sequence. The sequences Wheat-Chickpea-Mustard-Mustard and Wheat-Wheat-Mustard-Mustard produced the highest mustard glucosinolates; an important compound for industrial processes. Mustard used significantly more soil moisture than wheat or chickpea, however the levels of soil sulphur and phosphorous after harvest were much higher after mustard. This was offset by generally lower levels of soil N and soil carbon compared to wheat and chickpea. The Wheat-Chickpea-Chickpea-Mustard sequence used more of the available phosphorous, nitrogen and sulphur than other mustard crop sequences and made better use of the higher residual soil moisture retained in the soil after chickpea. The primary economic and environmental benefit to the grain-grower was enhanced yield of wheat following mustard. This research indicates that mustard production can be successfully expanded in a northern farming crop sequence.