Effect of varying fertilization treatment on the content and distribution of trace elements in harvested crops

The content and distribution of Fe, Mn, Zn and Cu in harvested crops under different long-term fertilization schemes were analyzed. Data from 18 years of continuous field trials in aquic-brown soils in a suburb of Shenyang, Northeast China were used in the study. Based on the study, the order of the trace elements in the harvested crops in relation to content is as follows: Fe> Mn, Zn>Cu. The content of the trace elements in maize is higher than that in soybean. There are extreme differences in the content of trace elements among different fertilization treatments, generally occurring in the order of NPK+M>NPK>M>CK. There is a significant correlation between trace element content and grain yield/stalk yield.R² regression trends of Fe, Mn, Zn and Cu contents in maize harvests and stalks yield are 0.99, 0.94, 0.92 and 0.87 respectively. R² regression trends of Fe and Mn content in soybean harvests and stalks yield are all 0.97, while that of Zn and Cu content in soybean harvests and grain yield are 1.00 and 0.97 respectively. The distribution of trace elements varies with fertilization treatment. In maize, trace elements are mainly concentrated in stalks, whereas they are concentrated in grains for soybean. Nutrient cycling like straw re-use is therefore an effective strategy for sustainable agro-ecosystem. Extensive and intensive application of nutrients recycling like plowing straw into the soil should therefore be supported.