عنوان مقاله [English]
نویسنده [English]چکیده [English]
Introduction: Corn is an important plant because of its high grain and dry matter yield and nutritional value. This performance is possible with high level of inputs, while evidences suggest that excessive use of fertilizers reduce soil fertility and increase environmental pollution.On the other hand conventional soil manipulation methods are frequently led to soil degradation and erosion as well as loss of organic matter compared to conservation practices. The aim of this study was to investigate the effect of tillage management and fertilizer application on the yield and nutrient uptake of N, P and K in maize.
Materials and Methods: Two-year field experiment was conducted in Mashhad (north-east of Iran) during 2014-2015 and 2015-2016 growing seasons. The main plot factors of three tillage systems including minimum tillage (disk and furrower) and conventional tillage (moldboard plow + disk and furrower) and intensive tillage (two perpendicular moldboard plows + two disks and furrower). The sub factor was three fertilizer application rates including unfertilized control, 200 and 400 kg ha-1 urea fertilizer. Dry matter and grain yields were measured at the full ripening. Nitrogen and phosphorus uptake, utilization and use efficiency was calculated based on standard methods.
Results & Discussion: The main effects of the year, and nitrogen and the interaction effects of tillage by nitrogen and year by nitrogen on grain yield were significant. In the first year and in the minimum tillage, the highest grain yield of 8009.2 kg ha-1 was obtained which was not significantly different with the yield of same tillage in the second year. The results of this study showed that the highest corn grain yield of 8910.1 kg ha-1 was achieved when 400 kg ha-1 N and minimum tillage was applied which was significantly different from grain yield in the intensive and conventional tillage at the same level of N. In the first year and with minimum tillage, the highest nitrogen yield of 29.4 kg kg-1 was obtained, which was not significantly different with that of the second year. Also in the second year and in intensive and conventional tillage methods lower nitrogen productivity was obtained compared to the first year. Overall the highest nitrogen productivity of 35.2 kg kg-1 was obtained in the unfertilized control with minimum tillage which was not significantly different from that of intensive tillage but from conventional tillage.
Conclusion: Minimum tillage had more beneficial effects on enhancement of grain and dry matter yield and nutrient productivity of maize, in some cases even higher than conventional tillage. Therefore, it can be concluded that minimum tillage was able to improve the uptake of essential nutrients (P and N) and to increase the use efficiency of these nutrients. It can be inferred that in arid and semi-arid regions the application of conservation tillage may improve maize yield by enhancing nutrient productivity.
Keywords: Tillage, Productivity, Nitrogen, Yield, Phosphorus.