种植年限对设施大棚土壤次生盐渍化与酸化的影响

以京郊设施大棚为研究对象,分析了不同种植年限设施大棚土壤盐分含量、离子组成和pH值状况。结果表明,新建设施大棚在第3或第4年就出现了土壤次生盐渍化,5年以上的老设施大棚土壤电导率超标(0.5 m S·cm~(-1))率远高于新建设施大棚。设施大棚土壤盐分在0~20 cm表聚明显,盐分含量随着土层的加深而逐渐降低。盐基离子以SO_4~(2-)为主,其次是C~(2+);盐基离子含量大小顺序:阳离子为Ca~(2+)Na~+K~+Mg~(2+);阴离子为SO_4~(2-)HCO_3~-Cl~-。设施大棚土壤pH值随着种植年限的延长而下降;连续种植15年后,设施大棚土壤盐分平均增加了1.25倍,pH值平均下降9.3%。土壤次生盐渍化与酸化两者伴随出现,已成为限制设施生产可持续发展的重要障碍。

Effect of planting years on soil secondary salinity and soil acidification in greenhouse

In this study, soil salt content, ions components of salinity and soil pH value in greenhouse with different cropping years were analyzed . The results showed that newly greenhouse turned to secondary salinity soil in the 3th or 4th year. The probability of greenhouse soil electrical conductivity exceeded 0. 5 mS?cm-1 in over 5 years of old facilities were much higher than those of the newly ones. Soil salt were highly accumulated among 0~20 cm layer, and decreased with the increase of soil layer. Iongs components of salinity in soil were mainly SO2-4 and Ca2+, the order of ions were SO2-4 >HCO3- >Cl-and cations were Ca2+ >Na+ >K+ >Mg2+. Along with the increase of cropping years, pH value decreased obviously. After 15 continu-ous planting, the average soil salt increased by 1. 25 times, the average pH value decreased by 9. 3%. Soil secondary salinity accompanied by soil acidification, both of them became main obstacles to the sustainable development of the facilities produc-tion.