Trends in soil chemical fertility within the Herbert district

Herbert Cane Productivity Services Limited (HCPSL) has tested over 5000 soil samples from across the Herbert District since 2009. Individual soil nutrient levels were averaged each year and trends assessed. In general, there is a decline in soil fertility, although an increase in soil pH (1:5 soil to water) was observed, probably due to growers using lime as promoted by HCPSL’s amelioration extension program. However, downward trends in soil silicon (CaCl2) and phosphorus (H2SO4, BSES) levels were observed, with soils with low cation exchange capacity (sand and loam) approaching deficiency levels. There was a general trend of phosphorus mining of soils that have not received mill by-products. The results provide insights that will guide future soil fertility extension activities and research projects in the Herbert district.