Nitrogen and hydrogel combination in oat grains productivity

Hydroretentors in the soil can facilitate the maintenance of moisture and contribute to the efficiency of nitrogen use to the development of oat grains. The objective of the study is to verify if there is an efficiency increase of nitrogen use in oat grains productivity by the use of hydrogel and, if the hypothesis is confirmed, to define the optimal combination of N-fertilizer with the biopolymer in high succession systems and reduced N-residual release. The study was conducted in 2014 and 2015, in a randomized block design with four replicates in a 4 x 4 factorial, for hydrogel doses (0, 30, 60 and 120 kg ha-1), added in the furrow with the seed and N-fertilizer doses (0, 30, 60 and 120 kg ha-1), applied at the stage of 4th leaf expanded, respectively. The use of different doses of the hydroabsorbent biopolymer associated to the nitrogen fertilization in the cover influenced positively the productivity of oat grains, regardless of year and succession system. The adjusted dose of hydrogel and nitrogen at the maximum grain productivity in the soy/oat system is around 65 and 80 kg ha-1, respectively, and in the corn/oats system, 60 and 100 kg ha-1 respectively, regardless of the cultivation year.