增施磷石膏对苏北地区轻度盐碱土改良及小白菜生长的影响

Effects of phosphogypsum application on improvement of mild saline-alkali soil and growth of pakchoi (Brassica chinensis L.) in Northern Jiangsu province

为探明苏北地区盐碱土种植蔬菜时磷石膏的最适施用量,本研究以江苏省盐城市大丰区轻度盐碱土为供试土壤,小白菜为供试品种,采用云天化集团有限责任公司提供的磷石膏,设置4个施用量(0 g/kg、10 g/kg、20 g/kg、30 g/kg)进行盆栽试验,探究不同施用量的磷石膏对盐碱土化学性质及小白菜生长的影响。结果表明:在盐碱土中增施磷石膏,可以调节盐碱土的化学性质。随着磷石膏施用量的增加,土壤pH值逐渐降低,有机质、碱解氮含量总体呈增加趋势,但较对照差异并不显著;速效磷含量较对照极显著提高;土壤电导率、含盐量也逐渐提高。适宜的磷石膏施用量利于盐碱土改良,过高的磷石膏施用量会加重盐害。在盐碱土中适量增施磷石膏,能促进小白菜生长,提高其生物量。在磷石膏低施用量(10 g/kg)处理中,小白菜发芽率、株高、叶片数、叶面积、叶绿素含量、根长、根系活力、生物量等各项指标均最优,随着磷石膏施用量的继续增加(20 g/kg、30 g/kg),小白菜的发芽率降低,生长受到抑制,施用量越高,抑制作用越明显。在本研究中,磷石膏施用量以10 g/kg为佳,田间施用量可确定在7500~11250 kg/hm^(2)范围内,具体施用量还需结合田间试验进一步验证。

To find out the optimum dosage of phosphogypsum for growing vegetable in saline-alkali soil in northern areas of Jiangsu province,this study took mild saline-alkali soil in Dafeng District of Yancheng City,Jiangsu province as the test soil and pakchoi(Brassica chinensis L.)as the test variety,and used the phosphogypsum provided by Yuntianhua Group.Four dosages of application amount(0 g/kg,10 g/kg,20 g/kg,and 30 g/kg)were set up for pot experiments to explore effects of different dosages of phosphogypsum on saline-alkali soil chemical properties and effects on the growth of Chinese cabbage.The results showed that adding phosphogypsum into saline-alkali soil can regulate the chemical properties of the soil.With the increase of phosphogypsum application amount,soil pH value gradually decreased,organic matter and alkali-hydrolyzed nitrogen content showed an increasing trend as a whole,but the difference was not significant compared with the data of CK.The content of available phosphorus was extremely significantly higher than that of the CK.Soil conductivity,salt content also gradually increased.Suitable dosage of phosphogypsum was conducive to the improvement of saline-alkali soil,while excessive dosage of phosphogypsum might aggravate the salt damage.Adding appropriate amount of phosphogypsum into saline-alkali soil could promote the growth and biomass of pakchoi.The germination rate,plant height,leaf number,leaf area,chlorophyll content,root length,root activity,biomass and other indices of pakchoi were the best in the treatment with low dosage of phosphogypsum(10 g/kg).With the continued increase of the application amount of phosphogypsum(20 g/kg,30 g/kg),the germination rate of pakchoi was reduced and the growth was inhibited.The higher the application amount,the more obvious the inhibition effect was.In this study,10 g/kg phosphogypsum is the best dosage,and the field application amount can be determined within the range of 7500-11250 kg/hm^(2).The specific application amount needs to be further verified by field experiments.