湖南省柑橘园土壤硫素及施硫效应研究

Soil sulphur status and citrus sulphur application response

为了探明湖南省柑橘园土壤硫素含量丰缺程度和柑橘施硫效应,2000～2004年开展了柑橘园土壤硫素含量调查与田间试验研究.结果表明,湖南省柑橘园0-20cm土层有效硫含量平均为47.7 mg/gk,低于临界值的占9.9%、潜在缺硫的占17.3%.随着土层加深,有效硫含量逐渐增加、全硫含量依次减少.土壤有效硫的地区分布,0-20 cm土层,81.3%的调查县中有10.0%～75.0%的柑橘园存在缺硫和潜在缺硫.柑橘叶片全硫含量平均为2.32g/kg,有27.2%的柑橘园低于临界值.在有效硫含量不同的土壤中,柑橘连续4～5年施硫肥平均增产5.3%～30.0%,4个基点平均增产10.7%.连续施硫肥明显提高了柑橘叶片硫和氮含量,柑橘果皮中硫含量提高、氮含量降低,有利于果实品质的改善.施硫肥的增产优质效应表现为有效硫含量缺乏的土壤＞潜在缺乏土壤＞中等和丰富土壤;较长树龄＞较短树龄.随着施硫肥年数延长,施硫增产优质效应更加明显.

In order to investigate the status of soil S in citrus gardens in Hunan Province and citrus in response to S application, we carried out a survey of soil S in 81 citrus gardens, and conducted field experiments in 4 citrus gardens of Taoyuan county and Zhuzhou county of Hunan Province during 2000-2004. Results showed that for available S content at the surface 0-20 cm layer of citrus gardens soils, 9.9% was lower than critical level, and 17.3% was potentially deficiency （average 47.7 mg/kg）. Soil available S content increased gradually with increase in soil depth, whereas total S content decreased stepwise. Regarding the available S regional distribution, there were 10.0%-75.0% citrus gardens that soil available S in 0-20 cm soil layer was deficient or potentially deficient in 81.3 % of all the investigated counties. The citrus garden in which total S content of citrus leaves was lower than critical value accounted for 27.2% （average 2.32 g/kg）. Field experiments results showed that citrus yields increased by 5.3 %-30.0% after continuous S fertilization for 4-5 years. Continuous S fertilization evidently enhanced S and N content in citrus leaves and S content in citrus fruit skin, reduced N content in citrus fruit skin, consequently improved quality of fruit. The order of yield and quality response to S fertilization was as follows ： Available S deficient soil 〉 available S latent deficient soil 〉 available S medium and sufficient soil, and older tree - ages 〉 younger tree - ages. With the years of S fertilizer application extending, the yield and quality response of S fertilization became more distinctively.