Research On The Effects Of Cbbf On Watermelon Growing And Its Soil Environment

The application of controlled-release BB fertilizer (CBBF) which was a kind of environment-protecting fertilizer met the requirements of the sustainable development of agriculture. Studies showed that nutrient release of CBBF was accordant with plant uptake of nutrients, contributing to increasing crop yields, improving crop quality and enhancing nutrient use efficiency.Two types of CBBF used in this study were manufactured by Shandong Kingenta Engineering Co., Ltd. By studying the CBBF release features in different media and watermelon field trials, systematically studied the laws of nutrient release and its effect on the watermelon, initially identified the superiority of CBBF on watermelon, and provided a theoretical basis and technical parameters for the future research and application of CBBF on watermelon. Main results were summarized as follows:1. CBBF showed similar nutrient release patterns, but different release rate in water and soil. The accumulative nutrient release curves of nitrogen (N), phosphorous (P) and potassium (K) in water all showed curve of"S"and could be divided into three stages---slow release period, peak period, and decreased period. The characteristic equations of nitrogen release in different CBBF were identical, and the R2 numerical value of regression equation overtopped 0.98, it indicated that estimation of quasi-conjunction of polynomial function was preferable and regression equation could reflect the nutrient release characteristic of CBBF perfectly.2. Effects of CBBF on plant growth and development of watermelon: The main vine length, leaf number, leaf length, leaf width and leaf area of CRF1 were significantly higher than other treatments; the contents of nitrate in the leaves of CBBF were remarkably lower than the CCF treatment, while the content of chlorophyll were higher than the CCF treatment. The nitrogen utilization of CRF1,CRF2 and CRF3 could be increased by 38.13%, 27.79% and 37.08% of CCF.3. Effects of CBBF on yield of watermelon: The yield variation of single plant was: CRF1> CRF2> CRF3> CCF> CK, and the differences among these treatment were significant; the yield of CRF1, CRF2, and CRF3 can be increased by 20.18%, 8.69% and 3.94% respectively; In addition, the economic coefficient and fertilizer productivity of CRF1, CRF2, and CRF3 were also higher than CCF, in which the fertilizer productivity was 2.14 times, 1.86 times and 1.22 times of CCF respectively.4. Effects of CBBF on quality of watermelon fruit: The vitamin C content of CRF1, CRF2, and CRF3 could be improved by 65.10%,48.74% and 56.92% of CCF; the center ,edge soluble sugar content and sugar-acid ratio of CRF3 were remarkably higher than other treatments, The secondary CRF1 and CRF2 were also larger than the CCF; The ratio of the center sugar/edge sugar of CRF3 was the smallest, so its edible rate was higher compared with other treatments, the difference between CRF1 and CRF2 was not significant, which were less than CCF; the content of fruits nitrate of CRF1, CRF2 and CRF3 were significantly lower than the CCF.5. Effects of CBBF on characters of physics and chemistry of soil:The content of alkali-nitrogen of CRF1 was the highest, while the contents of soil available phosphorus and available potassium of CRF3 were the highest; compared to the CCF, the available N, P, K of three CBBF treatments had the release properties of lagging behind, which basically reached the peak of its nutrient release when the watermelon was in the expanding period, whose release character was something similar to the nutrient requirements of watermelon at different growing stages; the content of NH4+-N, NO3--N, inorganic phosphorus and K+ in the surface runoff of CBBF were clearly lower than CCF, which significantly reduced the loss of nutrient and the potential pollution of surface water and groundwater due to fertilizer application.6. Effects of CBBF on enzyme activity in soil: The phosphatase activity of the fertilization treatments were lower than CK, indicating that fertilization on soil could inhibit the phosphatase activity; the activities of soil unease, catalase and sucrose of CRF1, CRF2 and CRF3 reached a maximum when the watermelon was in the expanding period, and they were all greater than the CCF. The enzyme activity of CRF1 was the highest, while the difference between CRF2 and CRF3 was not significant. The results showed that the effects of CRF1 on soil enzyme activities were the greatest.