Effect Of N,P,K Fertilizer On Growth And Physiological Characteristics Of Taro

Taro is a kind of important special local vegetable that can earn foreign exchange. But the research about fertilization and mineral nutrition absorption and distribution in taro is rare. The phenomenon of applying fertilizer blindly exists on production, which influence yield and quality very much, and decrease the benefit of taro production. For this reason, this paper studied the effect of nitrogen, phosphorus and potassium on taro's growth and development, yield, quality, absorption and distribution of nutrition element. The material is "laiyang taro". With the design of double orthogonal regression, we studied the effect of N and K fertilizer. Four treatments (0Kg/667m2, 7.5 Kg/667m2, 15 Kg/667m2, 22.5 Kg/667m2) were applied to study the effect of P on taro growth. In the meantime, we also studied the morphological and physiological characteristics changes of taro. Analyzed by computer, we determined the optimizations of taro fertilizer, and offered the scientific theoretical foundation for applying fertilizer rationally in taro. The main results were as follows:1. N, P, K affected taro's growth. In a certain range, plant growth increased when the quantity of fertilizer increased. But if the quantity were too much, the growth would decrease.2. N, P, K affected Physiological characteristics of taro. If usage of N, P and K is reasonable, taro's electrolytic leakage and mlondiadehyde content reduced, the damage of film is little. If using excessive or too little fertilizer, superoxide dismutase activity, catalase activity of taro leaves improved, peroxide activity decreased, proline content and content of soluble sugar increased.3. N, P, K affected the taro's ability of utilizing nutrition. It also affected the absorption and distribution of mineral nutrition. When usage of N, P and K is reasonable, its root system activity improved, NR activity increased. The absorption amount of N, P, K, Ca, Mg, Fe, Mn, Cu and Zn is increased too. The amount which distributed to rhizome was also augmented ,which helped to improve economic coefficient. 4. N, P, K affected taro's photosynthesis ability. When the ratio of N and K is reasonable, chlorophyll content and photosynthetic rate are high. The period of high light effect is long. Photosynthetic rate in later period of corm vigorous growth stage deceased slowly and photosynthetic matter accumulated more.5.N, P and K affected the yield and quality of taro. If the proportion of N and K is reasonable, content of starch, protein, soluble sugar, rough protein, rough fat and rough fibre are high. K had more influence than N, and N, K had district mutual effect. In this experiment, if usage of N and K are below 17.45kg/667m2,50.50kg/667m2, yield would increase with the increase of fertilizer. But if used too much fertilizer, yield would decrease. The fertilizer plan of highest yield is N 13.64kg/667m2,K2O 54.65kg/667m2. If usage of N and K are below 19.21kg/667m2,48.20kg/667m2, quality would increase with the increase of fertilizer. If used too much fertilizer, quality would decrease. The fertilizer plan of highest quality is N 13.64kg/667m2, K2O 54.65kg/667m2. In this experiment, the optimal usage of P is 15Kg/667m2, yield could reach 2649kg/667m2.