Soil mapping in modern high-density apple orchards

Abstract

The use of EM38 soil mapping prior to planting has potential to provide significant benefit to the apple industry through informing soil amelioration work to improve soil homogeneity across orchard blocks. Reducing soil variability increases the chances of growing a uniform block of trees, which is essential for optimal productivity and efficient labour-use. This project aimed to determine a) if there is a relationship between soil zones defined by EM38 mapping, and productivity in apple orchard blocks, and b) if a relationship does exist, investigate whether productivity might be improved by conducting EM38 mapping prior to planting. EM38 soil maps, soil samples and tree productivity maps were collected and analysed from two high-density orchard blocks in the Stanthorpe region of Queensland. The results showed existence of a broad relationship between EM38 mapping zones and areas of high and low productivity in both blocks. Further data investigation and discussions with growers, suggested that use of the EM38 soil maps, together with grower knowledge of the site history, would have likely led to improved soil amelioration work prior to planting and changes to block design. This may have resulted in reduced variability in productivity and therefore greater profitability. It was concluded that EM38 soil mapping could be a cost-effective technology for guiding decision making at the point of site preparation and has significant potential to add value to orchard businesses. The combination of EM38 soil mapping with yield, and Normalized Difference Vegetation Index mapping technologies will likely provide greatest value in the future, particularly in the preparation of apple orchards for the use of robotics