Micronutrients or trace elements are an essential part of crop nutrition. They are as important as the better-known macronutrients nitrogen, phosphorus and potassium. This was a key message on the southern tour of the MPCN II Roadshow in August 2016.
Scott and Jillian Vaessen farm at Tabbita in southern NSW. Their property was the first stop in the southern leg of the Roadshow. Scott conducts annual soil tests to gauge soil nutrient status. Soil phosphorus levels have been an issue in the past. But recent tests show his soils are very low in zinc and copper.
Nigel Wilhelm from SARDI explained there are over 16 essential nutrients for crops. These include micronutrients such as manganese, zinc, copper, and boron. Tissue tests are more reliable for detecting micronutrient deficiencies than soil testing. They are also useful for clarifying visual crop symptoms. Many visual symptoms of deficiency resemble diseases.
Signs of zinc deficiency appear early in the season in cereals. Affected plants will have two pale stripes running the length of young leaves. Address this by applying a zinc foliar spray at the two-leaf stage. In a known zinc-deficient paddock, apply a seed dressing with added zinc before sowing.
Scott’s cropping enterprises face many complex production challenges. But he believes developments in plant genetics will help overcome them. Breeding can improve things like tolerance to frost and heat stress. Growers could choose plant cultivars to suit seasonal outlook, soil nutrient, and moisture levels.
Scott sees precision agriculture as remaining an important tool for cropping. He uses yield and precision soil mapping to create paddock zones. This enables him to improve fertiliser use efficiency. Scott is using these technologies to work towards achieving even crop yields across paddocks.
More detail on Scott Vaessen’s cropping system: MPCN SCOTT VAESSEN Case Study