Effects Of Nitrogen Fertilizer Level And Morphology On Yield, Quality And Silage Quality Of Italian Ryegrass

In the south of China, natural grass withered in winter and spring which causes a serious shortage of forage. Planted ryegrass can effectively increase the forage yield. The ryegrass silage can also balance the supply of high quality forage. The experiment applied Italian ryegrass with different levels and forms of nitrogen fertilizer to investigate the effect of nitrogen fertilizer on yield, nutritive value and silage quality of Italian ryegrass, and then to determine the optimum amount and form of nitrogen fertilizer. It aims to provide a scientific basis for Italian ryegrass with high quality, high yield, sustainable production and utilization in southwest region of China. Test results were as follows:1. After applying 150kg/hm2,300kg/hm2 and 450kg/hm2 pure nitrogen to Italian ryegrass, with the increase of the amount of nitrogen, the yield was increased. The yield of 450kg/hm2 nitrogen fertilizer application block is 35% higher than 150kg/hm2 application block. Plant height and tiller number have a certain content of increase.2. The application of nitrogen can increase the nutritive value of Italian ryegrass. Within a certain range, the higher the amount of nitrogen fertilizer, the higher crude protein content, the better palatability, the lower neutral detergent fiber and acid detergent fiber content. But excessive nitrogen fertilizer results the decrease of carbohydrate content. This leads insufficient energy supply, and silage is not easy to succeed.3. There is a close relation between silage quality and raw material nutritive value of Italian ryegrass. The higher the nutritional quality of raw material, the higher the quality of silage. Silage sensory quality and V-Score of 300kg/hm2 nitrogen fertilizer application are highest. At the same time, the content of crude protein, neutral detergent fiber, acid detergent fiber, water soluble carbohydrate and crude fat achieve the best compared with other two nitrogen levels. But excessive nitrogen fertilizer lead the excessive content of ammonia and nitrate nitrogen which easy to cause livestock poisoning.4. The experiment sets three forms of nitrogen, amide nitrogen (urea), ammonia nitrogen (ammonium bicarbonate) and nitrate (nitrate fertilizer complex). All the three kinds of nitrogen have improvement on yield of Italian Ryegrass. Among them, amide nitrogen have the highest efficiency, followed by nitrate, and finally ammonia nitrogen.5.The form of nitrogen also have impact on nutritive value of Italian ryegrass. amide nitrogencan be better absorbed by Italian ryegrass. With the same amount of nitrogen fertilizer, the amide nitrogen contains a high crude protein (CP) level than ammonia nitrogen and nitrate, but the content of fiber in amide nitrogen is lowest while the water soluble carbohydrate content in amide nitrogen is only slightly lower than ammonia nitrogen and nitrate. Comprehensive comparison, under the same amount of nitrogen fertilizer, amide nitrogen can get a higher quality of Italian Ryegrass.6.The form of nitrogen also have significantly impact on silage quality of Italian ryegrass. From the V-Score, the silage with application amide nitrogen is superior. The application of ammonia nitrogen is good, because it results the increase of ammonia content in silage which impact silage quality. But the excessive application of nitrate results the increase of nitrate content in silage which can arrive the level of poison.