湖南省茶园土壤养分丰缺指标及配方施肥

Study on Nutrient Scale of Sufficiency or Deficiency in Tea Soils in Hunan Province and Fertilizing Recommendation

对湖南省３６个县（市）６７个茶场的１３６份茶园土样进行了肥力水平测定。结果表明：茶园土壤ｐＨ适宜，钾素较丰富。土壤有机质含量０～２０ｃｍ土层为（２．４±０．０９）％，２０～４０ｃｍ土层（１．６０±０．０６）％。８５％的土样０～２０ｃｍ土层有机质含量超过１．５％，３８％的土样超过２．５％；４９％的土样２０～４０ｃｍ土层的有机质含量超过１．５％。全氮含量０～２０ｃｍ土层为（０．１３３±０．００４）％，２０～４０ｃｍ土层为（０．１００±０．００３）％。碱解氮含量大于１００ｍｇ／ｋｇ土的土样占７６％，２０～４０ｃｍ占４５％。全磷含量低于０．１％的０～２０ｃｍ土层达５３％，２０～４０ｃｍ土层达６２％。速效磷含量低于１０ｍｇ／ｋｇ土的频率，两土层各为４６％和６５％，显示低磷土壤较多。代换性镁含量较低，茶园严重缺镁。依据调查结果，建立了茶园土壤主要养分与茶叶产量之间的数学模型，据此提出了茶园土壤养分的丰缺指标：产量在２２５０ｋｇ／ｈｍ２干茶的茶园土壤０～４０ｃｍ土层全磷（Ｐ２Ｏ５）含量＞０．１２％，碱解氮含量＞１４９ｍｇ／ｋｇ土，速效磷含量＞３２ｍｇ／ｋｇ土，速效钾含量＞１１０ｍｇ／ｋｇ土。通过试验，确定了４种主要土类适?

Fertility of 136 soil samples in 67 tea plantations from 36 counties of Hunan Province were tested. Results showed that the pH of the soils were generally suitable for tea. The average content of organic matter was (2.4±0.09)% for the 0-20 cm soil layer and (1.6±0.06)% for the 20-40 cm. Contents of organic matter in 85% samples of the 0-20 cm layer were over 1.5%, those in 38% samples of the same layer were over 2.5%, and those in 49% samples of the 20-40 cm layer were over 1.5%. The average content of total N was (0.133±0.004)% for the 0-20 cm layer and (0.100±0.003)% for the 20-40 cm layer. Samples with an available N content of over 100 mg/kg occupied 76% of the total samples of the 0-20 cm layer, and 45% of those of the 20-40 cm layer. Samples with a total P content of below 0.1% occupied 53% of the total samples of the 0-20 cm layer, and 62% of those of the 20-40 cm layer. Samples with an available P content of below 10 mg/kg occupied 46% of the total samples of the 0-20 cm layer, and 65% of those of the 20-40 cm layer, indicating the deficiency of P in many soils. The exchangeable Mg was so low that the soils were seriously deficient in Mg nutrition. Based on the investigation, a mathematical equation between the major nutrients in tea soils and the yield of tea was established and a scale of nutrient sufficiency or deficiency was proposed. In the 0-40 cm soil layer, the total P (P 2O 5), the available N, P and K should be maintaned above 0.12%, 149 mg/kg,32mg/kg and 110 mg/kg respectively to obtain the yield of 2 250 kg/hm 2 made tea. In addition, pot and field experiments in 4 types of tea soil were carried out to evaluate the effects of different nutrient (N, P, K) formula. The suitable nutrient ratio was 1∶1∶1 for red earth developed from granite and lime stone, and 2∶1∶1 for that developed from slate shale and quaternary red clay. A new special compound fertilizer for tea thereafter was developed according to the results on the nutrient ratios. Field and pot experiments and large scale demonstration indicated that the fertilizer was significantly effective in increasing yield, improving quality and increasing the economic benefit as compared with single urea of same price or nitrogen content.