Tuber Yield and Leaf Concentration Of Nitrogen and Sulfur In Potato Cultivated In Sandy Soil As Affected By Management Of The Entec 26 Nitrogen Fertilizer.

To improve the use efficiency of the N by crops, the nitrogen sidedressing fertilization and use of the fertilizer with nitrification inhibitor has been used to increase the availability time of the N in the sandy soils. The objective of this study was to evaluate the Entec 26 nitrogen fertilizer management on potato cultivated in sandy soil. Tree experiments were carried out an experimental field, with four blocks in a randomized block design, was cultivated with potato var. Ágata in the southeastern São Paulo State, Brazil (at São Manuel, and Avaré). It was compared nitrogen and sulfur leaf concentration, yield of total and commercial tuber class of potato (diameter > 23 mm) among two rates (120 e 160 kg ha^-1) of Entec 26, nitrogen fertilizer with nitrification inhibitor. The N application was divided in 40 kg N ha^-1 at planting and the remainder N (80 e 120 kg ha^-1) was sidedressed at the hilling time. In addition, replications with no N application were used as control treatment. The N sidedressed treatments increased N concentration in leaves, and S concentration was not affected by treatments. The nitrogen sidedressing fertilization treatment increased the yield of total and commercial tuber class of potato.

Key words: Solanum tuberosum, management, yield, nutrition.