Assessment of the Biological IMPACT of Introducing Mustard into a Typical CROP Rotation on the Northwestern Plains of NSW.

ASSESSMENT OF THE BIOLOGICAL IMPACT OF INTRODUCING MUSTARD INTO A TYPICAL CROP ROTATION ON THE NORTHWESTERN PLAINS OF NSW

 

Makhdum Azam Ashrafi (Student ID 440626309), School of Life and Environmental Sciences, Faculty of Science, The University of Sydney

Supervised by

Dr. Helen Bramley, Prof. Richard Trethowan, Associate Prof. Michael Kertesz ABSTRACT:

The aim of this study is to examine the impact of mustard (which has allelopathic effects) in rotation with wheat and chickpea on crop productivity, soil and stubble borne diseases, soil nutrition and moisture as well as microbial communities. The outcome will be identification of sustainable and profitable solutions for farmers in northwestern NSW, Australia.

Different rotation combinations of wheat, mustard and chickpea were sown on a deep vertisols soil over 4 years. A range of crop growth, phenological, physiological and yield parameters were measured, along with incidence of disease (above and below ground) and nodulation of chickpea.

At 30 and 45 days after sowing, chickpea did not show much variation in number of plants, nodes, tillers and leaves, canopy cover %, number and weight of nodule in different rotational treatments, but during later development, chickpea was more productive (yield and biomass) where mustard and wheat were present in the rotation. This was associated with less ascochyta blight and sclerotinia rot incidences and highest canopy cover %, NDVI, number of plants, plant heights and number and weight of nodules at anthesis. Wheat was infected by yellow leaf spot within one month of sowing in continuous cultivation of wheat (2 or 3 years) and was adversely impacted after three consecutive years of mustard cultivation, both of which reduced growth and productivity as indicated by the lowest number of effective tiller, NDVI, canopy cover % and yield.

Because glucosinolates released from mustard tissue impede the growth of soil microbes, they may also impede the growth of beneficial organisms like mycorrhizae. Therefore, more research is needed to examine the colonization of mycorrhizae on crop roots.