The efficiency of nitrogen stabilizer at different soil temperatures on the physiological development and productivity of maize (Zea mays L.)

D. Rácz¹, B. Gila², É. Horváth¹, Á. Illés¹ and A. Széles¹

¹University of Debrecen, Faculty of Agriculture and Food Sciences and Environmental Management, Institute of Land Use, Technology and Regional Development, Böszörményi út 138, H-4032 Debrecen, Hungary
²University of Debrecen, Faculty of Science and Technology, Department of Molecular Biotechnology and Microbiology, Egyetem tér 1, H-4032 Debrecen, Hungary
*Correspondence: racz.dalma@agr.unideb.hu

Abstract:

Nitrogen (N) stabilizer containing nitrapyrin inhibitor is responsible for slowing the activity of Nitrosomonas sp. bacteria down which oxidize ammonium to nitrite ions, thus, N-loss resulting from nitrate leaching can be reduced. Although prior studies have shown its effectiveness in the pre-sowing application in maize, considering that it disturbs the activity of Nitrosomonas bacteria which is the most intense between 25 °C and 30 °C, soil temperature may significantly influence the efficiency of nitrapyrin. Besides, nitrapyrin aims to enhance N-use efficiency in high N-demanding plants, such as maize, which demands N at the most during stalk elongation, which lays down the reason for its subsequent application. This study focuses on the efficiency of nitrapyrin at different soil temperatures and its impacts on the physiological development and productivity of maize. In a laboratory test, 10 °C, 15 °C, 20 °C, and 25 °C temperature soils were treated with nitrapyrin and change of nitrate content was monitored to observe the nitrification dynamic. Results show that as the soil temperature elevated, the inhibition efficiency increased. In a field experiment with maize, nitrapyrin was applied in 13 °C and 25 °C temperature soil. Results suggest the later treatment enhanced N-use efficiency, as, during the high N-demanding growth stage, more N-forms were available in the soil. This resulted in significantly higher relative chlorophyll concentration in the leaves and laboratory leaf analysis confirmed the prevention of N deficiency. Results of further measurements on parameters indicating biomass production such as root mass, stalk diameter, ear size, 1,000-kernel weight indicate that the nitrapyrin application should be timed later.

Key words:

corn, nitrapyrin, nitrification inhibitor, nitrogen use, Nitrosomonas

Effect of nitrogen rate and forecrop on nitrogen use efficiency in winter wheat (Triticum aestivum)

L. Litke*, Z. Gaile and A. Ruža

Latvia University of Life Sciences and Technologies, Institute of Soil and Plant Sciences
2 Liela street, LV-3001 Jelgava, Latvia
*Correspondence: linda.litke@llu.lv

Abstract:

Application of plant nutrient is one of the most important measures increasing grain yield and yield quality. Excessive application of nitrogen fertilizers leads to nitrogen leaching and it affects the quality of groundwater and surface water. The objective of this research was to evaluate the effect of nitrogen fertilizer rate on nitrogen use efficiency in winter wheat after two forecrops. The experiment was conducted at the Research and Study farm ‘Pēterlauki’ of Latvia University of Life Sciences and Technologies (56° 30.658’ N and 23° 41.580’ E) in four growing seasons: 2014/2015, 2015/2016, 2016/2017 and 2017/2018. Researched factors were crop rotation (wheat/wheat and oilseed rape (Brassica napus ssp. oleifera/wheat) and five nitrogen fertilizer rates (kg ha^-1): N0 or control, N60, N120(90+30), N180(90+60+30) and N240(120+60+60). Nitrogen fertilizer affected winter wheat grain yield significantly (P < 0.001) and average grain yield increased significantly (P < 0.049) until nitrogen rate N180. But analyzing it after each forecrop separately, yield increased significantly (P < 0.05) until N120 after both forecrops. Nitrogen fertilizer affected nitrogen use efficiency (NUE), nitrogen uptake efficiency (NUpE), nitrogen utilization efficiency (NUtE) and protein content significantly (P < 0.001). When increasing nitrogen fertilizer rate NUE, NUpE and NUtE decreased, and higher results were observed at the lowest nitrogen rates. Increased nitrogen fertilizer rate also increased crude protein content in grain, and for bread baking suitable grain was obtained only with the highest N rate: N 240. Forecrop did not affect winter wheat grain yield, however, it affected NUtE (P < 0.01), NUE (P < 0.001) and nitrogen harvesting index (P < 0.001) significantly; higher results were observed when wheat was grown after wheat.

Key words: