The effect of new strategies of nitrogen application on nitrogen uptake and biomass production in potatoes (Solanum tuberosum) during growth

摘要

There is a high risk of nitrate leaching from the root zone in the weeks between planting and emergence of potato (Solarium tuberosum). The objective of the study was to test new techniques for nitrogen (N) application to potatoes at plant emergence and the efficiency of foliar applied urea during growth in order to reduce the demand of N fertiliser at the time of planting. Two types of split N application strategies, with only 40 kg N ha~(-1) band applied beneath the seed tubers at planting and 80 kg N ha~(-1) band applied at plant emergence or foliar applied after tuber initiation, were compared with the treatment of 120 kg N ha~(-1) band applied at planting. Results from the first of two experimental years showed that split application strategies resulted in slightly postponed plant development, but at final harvest there was no difference between treatments in terms of tuber yield and total N uptake. For all treatments about 50 kg N ha~(-1) were taken up by the crop in addition to the 120 kg N ha~(-1) applied. Recovery rates of the fertiliser applied in the crop at the growth stage of 20% plant senescence ranged between 62% and 70%. Thus, only 36% to 49% of the 170 kg N ha~(-1) taken up by the crop originated from the applied fertiliser. The largest ~(15)N recoveries of individual split doses were obtained if small rates of N were band applied at planting and when urea were foliar applied after tuber initiation.