The influence of different nitrogen forms and application time on winter wheat

Nitrogen is a key element in the plant's mineral nutrition, which determines the fertility and quality of agricultural crops, but the excess of nitrogen has a negative impact on the environment. To determine the influence of nitrogen forms and winter wheat development on the nitrogen, photosynthetic parameters and productivity of plant nutrition. Analysis of soil done using standard methods acts: P2O5 and K2O — A-L, pH of soil -potentiometer, mineral nitrogen (N-NO3 + N-NH4) - tintometer, total carbon - dry burning. Assimilation area of leaf - gage of WinDias, index of chlorophyll -spectrophotometer, level of nitrogen - method ofKjeldahl. The research was carried out at the Experimental Station of Aleksandras Stulginskis University during 2015-2016 on medium textured loamy carbonaceous leached soil -Calc(ar)i-Epihypogleyic Luvisols. The soil of the experimental field was the following: pHKCl 6.8-7.2; phosphorus (P2Os) - 423-429 mg kg"1; potassium (K20) -157-163 mg kg-1; humus - 2.47-2.82%. The researchers explored the winter wheat crop (Triticum aestivum L.) variety 'Skagen' fertilized with amide (N-NH2), ammonium (N-NH4) and nitrate (N-NO3) forms of nitrogen fertilizers in different tillering stages (BBCH 21-29). 7 days after winter wheat was fertilized, the level of mineral nitrogen in the soil was on average 23.9% higher using ammonium-nitrate nitrogen form fertilizers than using amide nitrogen form ones. The index of chlorophyll and the area of leaves were essentially higher when ammonium-nitrate and amide forms of nitrogen fertilizers were used. The biggest effect on the index of chlorophyll and the area of leaves was achieved 16 days after the start of vegetation when plants were fertilized with ammonium-nitrate fertilizers. Plants fertilized with ammonium-nitrate fertilizers gave the biggest yield 4 days after the start of vegetationVytauto Didžiojo universitetasŽemės ūkio akademij