暗沟对宁夏盐碱地土壤盐分和垂柳生长的影响

Effects of blind ditch on salt and weeping willow growth of saline-alkali soil in Ningxia

采用暗沟排盐技术,研究在施用改良剂和有机肥等配套措施的条件下,不同间距暗沟(3 m、6 m、9 m和15 m)对宁夏盐碱地pH、Ca^(2+)、Mg^(2+)、Na^+、电导率(EC)、钠吸比(SAR)、有机质(SOM)及垂柳生长的影响.结果表明:(1)改良前土壤的EC大于4.00 d S/m,改良后所有处理包括CK(无暗沟和有配套措施)的EC全都小于1.50 d S/m;60-80 cm和80-100 cm土层的EC值在各个处理间没有显著差异,而0-20 cm、20-40 cm和40-60 cm土层的CK与其他处理有显著差异(P<0.05).(2)改良前土壤的p H值基本都在9.00以上,改良后3 m、6 m、9 m和15 m间距暗沟以及CK(无暗沟和有配套措施)的p H基本都在8.50左右,但不同处理间p H值没有显著差异.(3)0-20 cm、20-40 cm土层中,暗沟处理的SAR显著低于CK(P<0.05),15 m间距暗沟的SAR大于3 m、6 m和9 m间距暗沟;其他土层中,各个处理间的SAR没有显著差异.(4)相比CK,暗沟处理的有机质含量显著降低(P<0.05),其中9 m间距暗沟的有机碳含量最高.(5)3 m、6 m、9m间距暗沟的垂柳生长状况显著好于15 m间距暗沟和CK的生长状况(P<0.05).综上,暗沟排盐技术配套其他措施能够有效地改良盐碱地,综合考虑暗沟设置成本和改良效果,9 m间距暗沟为最佳选择.

This study focused on the effects of different blind ditch spacing （3 m, 6 m, 9 m, and 15 m） on pH, Ca2＋, Mg2＋, Na＋, electrical conductivity （EC）, sodium adsorption ration （SAR）, and soil organic matter （SOM） of saline-alkali soil and growth of weeping willow （Salix babylonica） in Ningxia, China. Supplementary measures included applying organic fertilizer and modifiers. The results showed that 1） before improvement, EC was greater than 4.00 dS/m. After improvement, EC of all the treatments including CK （no blind ditch but with supplementary measures） was less than 1.50 dS/m. In the 60–80 cm and 80–100 cm soil layers, the EC was not significantly different among treatments. However, in the 0–20 cm, 20–40 cm, and 40–60 cm soil layers, EC of CK was significantly different from those of other treatments （P 〈 0.05）. 2） Before improvement, pH of the soil in most layers was greater than 9.00. After improvement, pH of all the treatments was around 8.50. However, there were no significant differences among treatments. 3） In the 0–20 cm and 20–40 cm soil layers, blind ditch-treated SAR was significantly lower than that of CK （P 〈 0.05）. SAR of 15 m blind ditch spacing was greater than that of 3 m, 6 m, and 9 m blind ditch spacing. However, in the other soil layers, there were no significant differences among treatments. 4） Compared with CK, blind ditch-treated SOM decreased significantly （P 〈 0.05）. Of the 3 m, 6 m, 9 m, and 15 m blind ditch spacing, SOM of 9 m was the highest. 5） The weeping willow growth conditions of 3 m, 6 m, and 9 m blind ditch spacing were significantly better than those of 15 m and CK （P 〈 0.05）. In conclusion, blind ditch drainage technology and other supporting measures can effectively improve saline-alkali soil. Moreover, considering the setup cost and improvement effects of blind ditches, 9 m blind ditch spacing is the best option.