Investment

This investment is designed to collect and collate data from a range of different soil types under plus and minus K fertiliser treatments to validate K responsiveness, and look to ascertain if current critical K values re accurate across all soil types. The investment is also designed to demonstrate the value of tissue testing to diagnose K deficiency and validate best practice methodologies of application including banding of K which has been shown to provide benefits vs topdressing, foliar application & claying
The investment will utilise replicated test strips on a range of different soils and sites which have been identified as 'K responsive', through soil and plant tissue analysis. This is designed to validate the diagnosis methodology and demonstrate the value of tissue testing for K compared to soil testing. At each site crop response data will be compared between 'strips' where large amount of K fertiliser is applied to overcome K deficiency and untreated control strip, to validate K responsiveness and examine current critical levels in soil and plants. Responsive sites may also be utilised for future small plot, K rate trials to better inform critical values and rate response curves for the relevant soil types from which data could be utilised to update the Better Fertiliser Decisions for Cropping database which was established as part of a GRDC investment. Please note this investment does not extend to rate response/critical value trials.
Also proposed in the scope of work is the establishment of 1 or 2 sites to demonstrate the benefits of broadcasting, banding, and foliar K application methods, and including interactions with claying of sandy soils. Water repellent sandy soils are sometimes ameliorated with additions of clay (mainly to overcome water repellency), and some clays contain K and prevent K leaching. This investment is designed to help grain growers diagnose where K deficiency is limiting their productivity and profitability, and to enable the most cost-effective applications of K fertiliser where it is needed the most, and to avoid wasteful applications where K deficiency is unlikely.
Communication and extension of this work to grower and adviser audiences is also required as well as establishing baseline metrics to enable the evaluation of the investment and any emerging future investment opportunities.