Exploring the Possibility of Discharge of Nitrogen from the Lower Part of the Soil by two Between-crops Plant of Perko and Buko in order to better Use and Prevent the Waste of Nitrogen

Abstract

Since the nitrogen is one of the essential elements of plant with high mobility and tremendous waste, some cover crops with improved root system probably can prevent leaching of this element. This study was done in Agricultural Research Station of Islamic Azad University of Karaj located in Mahdasht area during the crop year 2013-2014. This study was done by using factorial experiment in a randomized complete block design with two cultivars of Brassica family of Perko and Buko, 3 levels of nitrogen (N0, N150, N300) Kg per ha, from urea source (due to nitrogen use efficiency in Karaj) at two different depth of 0-30 and 30-60 cm of soil. The research results showed that the triple interaction of in-depth plant at nitrogen on root fresh weight, root dry weight, the percentage of nitrogen in depth of 30 cm, 60 cm depth of soil nitrogen, at probability level of 1% and the percentage of organic carbon (P <0.05) among the studied plants is significant. The comparisons showed that Buko at the highest amount of applied nitrogen in the soil (300 kg N ha) left less nitrogen in the soil. The lowest amount of nitrogen leaching was for a depth of 30 cm and at 150 kg of nitrogen per hectare which belonged to Perko. By using high levels of nitrogen in the soil the waste and leaching of this element was tremendous. Therefore, Perko root fresh weight and root dry weight at 150 kg nitrogen per hectare were the highest at 30 cm depth of soil. Control plants had low root dry weight yield and aerial dry weight yield. Buko root length at a 60 cm depth of soil was higher than Perko so that at this depth of soil Buko was capable than Perko in preventing the nitrogen waste. Buko at high levels of nitrogen had higher nitrogen percentage in root and aerial organ. The protein amount of aerial organ increased with enhancement of nitrogen absorption to plant organs. Buko had more protein than Perko. Buko total dry weight was more than Perko.