| In this study,3 experimental methods--the positioning survey,culture test and field experiment were combined to explore that in strongly acidic tea garden soils which had high selenium background, how to improve the effectiveness of selenium. Firstly, GPS positioning survey was used to monitor the the status of Jiangsu Province tea gardens, including soils acidification,the content of full selenium and the content of effective selenium.The results confirmed that the tea gardens’ soils in Yixing City, Jiangsu Provincewidespread full of Se.According to the pH valuesof Jiangsu Province in 2013,20 tea gardens’soils were measured, the results showed that tea garden soil acidification remains a serious phenomenon.All of the 20 Tea plantations’ soil pH values were lower than the optimum pH of 5.5 the growth of tea, wherein pH value of nine tea gardens soilswas less than 4.5 which belonged to highly acidic soils of tea, accounting for nearly half of the 45%.There were three tea plantation soil pH even lower than 4.0, the acidification phenomenon need to improve immediately.According to the analysed Jiangsu Province typical soil pH trends the decade from 2003 to 2013,and the annual mean soil pH on behalf of tea comparison showed that Jiangsu Province tea garden soil pH mean value lower than 4.5, which belonged to strongly acidic soil.2003-2011 years, the average pH value of the soil in Jiangsu Province tea gardens showed a declining trend, but from 2011 to 2013 showed an increasing trend.In the background of strongly acidic soils of high selenium tea, through the cultivation experiment to explore the effects of different phosphorus-containing materials to improve the chemical effectiveness of selenium in soil.The test material selected seven kinds of phosphorus-containing materials, namely,calcium magnesium phosphate, superphosphate, crab meal, bone meal, rock phosphate,Ca(H2PO4)2,K2HPO4.The Impacts of theseseven treatments on the effective selenium content of the soil were not identical.The low dosage, medium dosageof calcium magnesium phosphate fertilizer has little effect of increasing the effective selenium content on strongly acidic soils of high selenium.However, the higher dosage would cause the soil effective selenium content significantly increased.But the amount of materials was too large, it would reduce soil selenium content.SSP was only effective at high dosage of materials to increase soil effective selenium content.Different amounts of crab treatment were highly significant increases differences of soil selenium content, low dosage worked best.The every amount of bone treatment effectedwell on the soil, the amount of control effect reached 6 made the best.However if it connected with the actual production, overall costs and other factors, the amount of 1 could meet the requirements.Rock phosphate and bone meal had the similar effect, each dosage effectswere good, and higher dosage was better than the low dosage, but the low dosage treatments made the effective selenium contentincreased a lot, the combination of the economic cost, low dosage can achieve the desired effect.Ca(H2PO4)2 made the effects well,but high-volume dasage was bad than low-dosage effect and the difference was not significant. The 1 amount of K2HPO4 treatments made the results the best.In this study, a series of field experiments were carried out to investigate the effects of 6 different adjustment measures on the quality of highly acidic Se-rich soil for tea gardens. The 6 adjustment measures include calcium magnesium phosphate, superphosphate and calcium magnesium phosphate mixed with bio-organic fertilizer, each one has two dosages. Results showed that treatments in different kinds and dosage of phosphoric fertilizer all improved the content of available selenium. The efficiency using high-volume treatments, including calcium magnesium phosphate high volume, calcium magnesium phosphate mixed with bio-organic fertilizer high volume and superphosphate high dosage, was better than that of the normal dosage for 3 corresponding treatments. Moreover, at the same dosage, the calcium magnesium phosphate mixed with bio-organic fertilizer works more effectively. In addition, enhancement achieved by 6 kinds of treatments revealed a very significant level (P<0.01). The result made a great sense on improving the effectiveness of selenium and provided a theoretical basis as well as technical supports to the development of Se-rich tea industry in Jiangsu Province. |
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