Pages: 26-33
Published Date:
[ Abstract ]
Abstract: Nitrogen is one of the essential elements required for plant growth and has tremendous mobility and waste. Some cover crops with developed root system, as the nitrogen receiver plants, can make nitrogen available to the subsequent plant and increase its use efficiency. For this purpose, this research was performed during the crop year 92-93 at the Agricultural Research Station of Islamic Azad University of Karaj in the Mahdasht area. This study was carried out using factorial experiment in the form of a randomized complete block design with 4 replications.The experiment treatments consisted of two varieties of Brassica family, called Perko and Buko, were used as pre planting plants. The placement of 3 levels of nitrogen (N0, N150, N300) Kg per hectare, provided from urea source (given the nitrogen use efficiency in Karaj) in two different depths of 0-30 and 30-60 cm. The maize (703 single cross) cultivation was performed after pre-planting plants cultivation. The highest performance of maize dry matter was appertained to the highest level of applied nitrogen (300 Kg / ha). The lowest economic performance of maize grain as well as the lowest amount of nitrogen uptake of maize grain, the lowest crop efficiency in using nitrogen, the lowest efficiency in nitrogen uptake (Recovery ), pertained to the pre-planting plant (Perko) at a depth of 30 cm. The physiological efficiency of nitrogen use was reduced with increase in levels of nitrogen. The highest nitrogen productivity efficiency was obtained through cultivation of Perko and Buko without nitrogen consumption. The greatest amount of nitrogen uptake is observed when two cover crops namely Perko and Buko gave more nitrogen to the maize in the depth of 60 cm in the highest amount of nitrogen use (300kg / ha).
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