Effects Of Coupling Water And Fertilizer On Physiological Characteristics, Water And Fertilizer Absorption Of Broccoli Under Drip Irrigation

The objective of this project was to explore the effective way of fertilizer and water coupling utilization under the condition of drip irrigation. The test material for studying is broccoli ―Zhongqing No.9‖. Three Water levels, i.e. 1500、1200、900 m3/hm2 and four fertilizer levels, i.e. F1(N = 392.75 kg/hm2, P2O5 = 109.51 kg/hm2, K2 O = 286.26 kg/hm2)、F2(N = 314.2 kg/hm2, P2O5 = 87.61 kg/hm2, K2 O = 229.01 kg/hm2)、F3(N = 274.93 kg/hm2, P2O5 = 76.66 kg/hm2, K2 O = 200.38 kg/hm2)、F4(N = 235.65 kg/hm2, P2O5 = 65.71kg/hm2, K2 O = 171.76 kg/hm2) treatments were carried out. To determine the effects of water and fertilizer coupling under drip irrigation on quality, the following paprameters were measured: dry matter and nutrient accumulation, soil nutrition content, the key enzyme activity. The main results as follows:1. The effect of fertilizer treatments on chlorophyll content and water potential exhibited the order of F2>F1>F3>F4 at the same irrigation level, while the order of chlorophyll content and water potential in the treatment of irrigation was W1>W2>W3 at the same fertilization level. The PFP of NPK and the harvest index are W2>W1>W3. The chlorophyll content and water potential in W2F2 were higher.2. The amount of irrigation and fertilizer has remarkable effects on the contents of nitrate, soluble proteins and free amino acids(FAA) in broccoli. The contents of soluble proteins and FAA climb up and then decline with the reduction of fertilizer in the condition of the same irrigation. In the same fertilization, the minimum contents of soluble proteins and FAA is in the treatment scheme W3. The soluble proteins and free amino acids in W2F2 were higher.3. Advisable coupling of water and fertilizer is beneficial to the increments of dry matter accumulation and nutrients. At the harvest times, the dry matter accumulation of ball-flower is 29.95% of the plant reaching the peak in the treatment of W2F2. The accumulations of N and P are 66.02kg/hm2 and 77.62kg/hm2, which are maximum. And the accumulation of K gets its maximum in the treatment of W3F1.4. Soil total N content decreased with the increasing of soil depth in all the treatments. At the same fertilization level, soil total N content decreased with the decreasing of watering. However, at the same watering level, soil total N content showed the trend of firstly rising then falling down. Water W2 and fertilizer F2 treatment is beneficial to the transformation of available p in soil, can make better benefits. Soil available potassium content climb up and then decline with the reduction of fertilizer in the condition of the same irrigation. W2F2 treatment can effectively improve the soil nutrient content, reduce the deep soil leaching.5. Soil urease and invertase activity peaked in bulking stage, soil phosphatase activity along with the growth period of advance gradually reduce. 0-20 cm soil layer of soil enzyme activity is greater than 20-40 cm soil. Soil enzyme activity, under the condition of same fertilizer were characterized by W2>W1>W3; The same conditions of irrigation water, soil enzyme activity are characterized by F1>F2>F3>F4. The highest soil enzyme activity is the treatment of W2F2.Medium water and fertilization amount treatment, that is total irrigation volume is 1200 m3/hm2,fertilization amount: N 314.2 kg/hm2, P2O5 87.61 kg/hm2, K2 O 229.01 kg/hm2 are the appropriate irrigation and fertilization scheme for broccoli grows in HEXI area of Gansu province.