Impacts of Nitrogen Sources and Rates on Soil Chemical Attributes and Potato Nutrition and Yield in a Subtropical Environment

Abstract

Abstract The nutritional status of the plants, soil chemical attributes prior to vine killing, and the classified yield of tubers may characterize soil-plant interactions with nitrogen (N) side-dressing for potato cultivars, indicating the most appropriate source and rate at sidedressing in subtropical environment. Two experiments with potato cultivars Agata and Atlantic were carried out with the aim of evaluating the effect of N sources (urea, ammonium sulfate and calcium nitrate) and rates (70, 140 and 210 kg ha− 1) on sidedressing, plus a zero-N control treatment, in the southern Brazil. Discrete variations on nutrients in diagnostic leaves and on soil chemical attributes in the Agata experiment were not reflected in the maximum average increase of 69.0% (14.2 Mg ha− 1) in total tuber yields obtained with 152 kg N ha− 1 as ammonium sulfate or calcium nitrate, which did not differ in AE’s. For the Atlantic cultivar, urea rates were practically inert in soil and plant attributes, and the ammonium sulfate rates acidified the soil and increased their Al3+ contents in the ridges, reduced Ca and Mg foliar concentrations and did not increase marketable tuber yields. Calcium nitrate increased foliar N, Ca and Mg concentrations, increasing marketable tuber yields by 26.6% (7.3 Mg ha− 1) with 116.7% higher AE than other N sources. In subtropical acidic inceptisols with potentially available Al3+, 153 kg N ha− 1 as ammonium sulfate or calcium nitrate for cultivar Agata and 152 kg N ha− 1 as calcium nitrate for cultivar Atlantic are the best options for sidedressing fertilization.