Effects Of Nitrogen Application And Cutting Frequency On Yield And Quality Of Water Spinach

The forage and fodder are matter foundation of animal husbandry development. Without enough supply of forage, it will not have high quality, yield and efficiency of livestock production development. Water spinach (Ipomoea aquatica Forsk.) has great potential in forage production in agriculture region of South China due to its tolerance of high temperature and moisture, great adaptability, good regrowth characteristic and fine feed quality.A field experiment for studying effects of nitrogen application and cutting frequency on rule of growth, forage yield and quality of water spinach(Ipomoea aquatica Forsk.) was carried out in order to find out practical methods for high yield, quality and efficiency of water spinach in agriculture region of Nanjing.The results indicated that, plant height, leaf number and shoot number grew fast from July to September. The forage and dry matter yield significant positive correlated with plant height, leaf number and shoot number.Nitrogen application could significantly increase the plant height, shoot number, leaf number, chlorophyll content, yield and forage quality. With increasing nitrogen application rate, the stubble of the plant height, shoot number, leaf number, chlorophyll content tended to rise in the main. Forage production and the average crude protein content increased with increasing nitrogen application rate, However, there were not significant (p>0.05) between277.2and415.8kg/hm2nitrogen application rate.The total digestible dry matter yield when applicated nitrogen rate at415.8kg/hm2was significantly higher than the total nitrogen277.2kg/hm2processing at cutting five times in the whole growth period (April7,2008-October22),but not significant difference at cutting four times.The results showed that forage yield of aftergrass increased with increasing nitrogen application rate, but declined with increasing cutting frequency. However, difference of forage yield of aftergrass was not significant (p>0.05) between277.2and415.8kg/hm2nitrogen application rate. The forage yield positively correlated with plant height and leaf numbers, and positively correlated with shoot numbes under cutting4times. Moreover, crude protein content of the forage increased with increasing nitrogen application rate, but declined with increasing cutting frequency. In vitro dry matter digestibility of aftergrass increased with increasing nitrogen application rate in34.6～277.2kg/hm2, and with increasing cutting frequency.Nevertheless,the change of acid detergent fiber content was contrary to In vitro dry matter digestibility.