Nitrogen efficiency in wheat yield through the biopolymer hydrogel

<div><p>ABSTRACT Nitrogen use efficiency in wheat biomass and grain yields can be favored by the biopolymer hydrogel. The objective of the study was to analyze the use of the biopolymer hydrogel applied to the seed in the optimization of fertilizer-N on wheat biomass and grain yields, under different conditions of agricultural year and succession systems of high and reduced release of residual-N. In the study, two experiments were conducted, with different farming systems, soybean/wheat and maize/wheat, one to quantify the biomass yield rate and the other to determine grain yield. The experiments were conducted in the years 2014 and 2015, in a randomized block design with four replicates in a 4 x 4 factorial scheme, corresponding to hydrogel doses (0, 30, 60 and 120 kg ha-1) added in the groove along with the seed and N fertilizer rates (0, 30, 60 and 120 kg ha-1), applied as top-dressing. It is possible to improve the fertilizer-N efficiency by wheat using the biopolymer hydrogel for the production of biomass and grains. The highest wheat yield per kilogram of N supplied is obtained with 30 and 60 kg ha-1 of hydrogel, regardless of the year and succession system.</p></div

Simulation of wheat biomass yield by thermal time, rainfall and nitrogen

<div><p>ABSTRACT Wheat biomass yield focused on the production of quality silage is dependent on rainfall, temperature and nitrogen (N). The objective of the study was to validate the use of rainfall, thermal time and N as potential variables for the composition of the multiple linear regression model and simulation of wheat biomass yield for silage production under N supply conditions during the cycle, in the systems of succession. The study was conducted in 2012, 2013 and 2014, in randomized blocks with four replicates in 4 x 3 factorial, for N-fertilizer doses (0, 30, 60, 120 kg ha-1) and forms of N supply [single application (100%) in the stage V3 (third expanded leaf); split application (70%/30%) in the stages V3/V6 (third and sixth expanded leaves); split application (70%/30%) in the stages V3/E (third expanded leaf and beginning of grain filling)], respectively, in the systems soybean/wheat and maize/wheat. Rainfall and N are potential variables in the composition of the multiple linear regression model. Multiple linear regression models are efficient in the simulation of wheat biomass yield for silage under the N supply conditions during the cycle in the succession systems.</p></div

Single and split nitrogen dose in wheat yield indicators

<div><p>ABSTRACT Single or split nitrogen (N) supply can maximize the expression of wheat yield indicators. The objective of the study was to evaluate the greater N use efficiency on wheat yield indicators by the single and split N supply under favorable and unfavorable year conditions to the crop in succession system of high and reduced residual N release. The study was conducted in 2014 and 2015, in a randomized complete block design with four replicates in a 4 x 3 factorial, for N-fertilizer doses (0, 30, 60, 120 kg ha-1) and supply forms [full dose (100%) in the phenological stage V3 (third expanded leaf); split dose (70 and 30%) in the phenological stages V3/V6 (third and sixth expanded leaves, respectively) and; split dose (70 and 30%) in the phenological stages V3/R1 (third expanded leaf and early grain filling)], respectively, in soybean/wheat and maize/wheat cultivation systems. The highest N use efficiency for wheat yield was obtained with the single dose supply in favorable year of temperature and rainfall and with the split dose in the V3/V6 stages in unfavorable year, regardless of the succession system of high and reduced residual N release.</p></div