| Phyllostachys praecox belongs to Phyllostachys of Bambusoideae (Gramineae). Since 1980s, researchers have been exploring on its cultivation technique and summarized an intensive cultivation technique taking surplus fertilizing and winter mulching as the core. Such technique has already been conducted to gain bamboo early shooting, output increase and good economic benefits. But heavy chemical fertilizing and continues winter mulching have also caused serious soil problems. However, few studies are concerned with soil nutrient movement and water pollution in bamboo growing regions so far. By field investigation and position experiments, this thesis made a study on the relationship between Phyllostachys praecox's cultivation technique and water pollution around its growing regions.The main results were as follows:1) To make clear the condition of water pollution around the growing regions, water samples were collected from drainage canals and nearby rivers in main Phyllostachys praecox growing Regions of Zhejiang province. They were then analyzed and compared with water samples from water systems near natural forests. Results showed: Total nitrogen (TN) concentrations in the former two were 11.618mg·L-1and 6.253 mg·L-1 respectively, which were 32.0 and 17.2 times of the latter respectively. Total phosphorus concentration in the former two were 0.252 mg·L-1 and 0.095 mg·L-1 respectively, which were 10.1 and 3.8 times of the latter respectively. Soluble carbon (DOC) concentration in the former two were 24.80 and 16.55 mg·L-1 respectively, which were 5.02 and 3.35 times of the latter restively. Taking TN concentration as an indicator, surface water quality around the growing Regions was lessⅤclass. Its Fluoride, Chloride, and Sulphate concentrations were obviously higher than those in water samples from water systems near natural forests, though still under the national quality standard for surface water. It was also polluted by DOC and phosphorus.2) To discuss the inference on dynamics of nearby river water quality by scale cultivation, 3 water quality detection sections were set both in growing and non-growing regions. Leaching water was collected and analyzed once every two months from May 2006 to May 2007. It turned out that water quality in growing regions was significantly worse. All main water quality indexes were higher in growing regions than in non-growing regions. Total nitrogen, nitrate nitrogen, ammonia nitrogen, and organic nitrogen contents were lower in dry season than in flood season, yet total phosphorus, soluble carbon, chlorides and sulfate content were opposite. Total nitrogen concentration in water samples from growing regions was 3.15 times of that from non-growing regions, reaching 4.237mg·L-1. Nitrate-nitrogen concentration in the former reached 2.006 mg·L-1, that was 5.07 times of the latter. Ammonia nitrogen concentration in the former was 0.072 mg·L-1, which was 0.66 times higher than the latter. Total phosphorus concentration in the former was 2.39 times of the latter, which was up to 0.047 mg·L-1. Soluble carbon concentration in the former was 17.78mg·L-1, which was 2.87 times higher than the latter. Organic nitrogen and chlorides concentration were 23.003mg·L-1 and 25.751mg·L-1 respectively,which were 6.96 and 3.23 times of the latter respectively. Chloride concentration was 0.527 mg·L-1 in growing regions, while none was detected in non-growing regions.3)To reveal characteristics of nutrients in leaching water under different fertilizer levels, the location experiment was arranged in Phyllostachys praecox stands. Leaching water was collected and analyzed from May to October in 2007. Results demonstrated that there was a significant linear relation between the amount of leaching water and the precipitation. The concentrations of different forms of nitrogen raised consequently with the fertilizer applied increasing, so did the load of leaching loss. All the nutrients in leaching water gradually decreased from May to September, but rose significantly in October. So did the amount of leaching water. By practicing reducing, conventional, overabundance fertilization, the amount of nitrogen leaching loss was 18.495 kg·hm–2,37.318 kg·hm–2 and 59.821 kg·hm–2 respectively, accounting for 4.22%, 4.25% and 4.54% of total fertilizer applied respectively. The amount of phosphorus leaching loss was 1.944 kg·hm–2,2.355 kg·hm–2 and 3.017 kg·hm–2, accounting for 1.07%,0.65% and 0.56% of total fertilizer applied respectively. There was no significant difference of DOC concentration or its leaching amount in Phyllostachys praecox stands among each treatment, or in among each treatment. The average DOC amount was 41.760 mg·kg-1, and its leaching amount was 51.787～55.688 kg·hm–2, which is 72.1% of that without fertilizer. The Fluoride leaching amount of was 0.930～1.050 kg·hm–2.4)An experiment was carried out in 2007 in Lin'an in Zhejiang, to study roles of buffer strips(BS) in reducing nitrogen(N),phosphorus(P) and dissolved organic carbon(DOC) in leachate from intensivism management of Phyllostachys praecox. Results showed that Treatment BS significantly reduced N, P and DOC in leachate water. On 30 cm and 60 cm, the total net N intercepted of 38.500 kg·hm-2 and 30.800 kg·hm-2,accounting for 79.3% and 82.7% in leachate water, the total net P intercepted of 7.900 kg·hm-2 and 2.000 kg·hm-2,accounting for 87.8% and 83.3% in leachate water, the total net DOC intercepted of 59.200 kg·hm-2 and 27.800 kg·hm-2,accounting for 67.7% and 69.0% in leachate water. |
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