羧甲基纤维素钠对黄土高原新造耕地土壤改良效果

Effects of sodium carboxymethyl cellulose application on soil properties of new cultivating farmland in Loess Plateau

关键词:  黄土高原  新造耕地  土壤改良  羧甲基纤维素钠

Key words:  Loess Plateau  new cultivating farmland  soil improvement  sodium carboxymethyl cellulose

摘要:

基于陕西省延安市新造耕地土壤水分与养分的改良需求，以羧甲基纤维素钠(CMC-Na)为土壤改良剂，设置田间定位试验CK(CMC-Na 0 kg/hm²)、T1(CMC-Na 100 kg/hm²)、T2(CMC-Na 500 kg/hm²)、T3(CMC-Na 1 000 kg/hm²)和T4(CMC-Na 2 000 kg/hm²)5个处理，探究不同处理对新造耕地土壤水分、电导率与养分的影响。结果表明:1)在对照土壤含水量<16.3%的情况下，提高土壤含水量21.3%~120.9%；然而，在对照土壤含水量>16.3%的情况下，与处理的土壤含水量无显著差异。2)新造耕地土壤电导率随生长季出现逐渐降低趋势，不同CMC-Na施用量之间存在差异。3)施用CMC-Na主要影响土壤速效养分，对土壤全氮、全磷和全钾影响则较小。较低CMC-Na施用量的T1和T2处理可提高土壤硝态氮，较高CMC-Na施用量的T3和T4处理降低土壤硝态氮，提高土壤速效磷和速效钾含量，对新造耕地的土壤pH基本没有影响。4)较低CMC-Na施用量T1和T2处理的谷子产量分别提高6.4%和5.7%，较高CMC-Na施用量T3降低产量。因此，CMC-Na可提高土壤水分，并促进养分吸收利用，从而提高作物产量，可作为黄土高原新造耕地土壤改良剂，推荐施用量约100 kg/hm²。

Abstract:

Based on the requirement of soil water and nutrient improvement of new cultivating farmland of Loess Plateau in Yan'an, Shaanxi Province, sodium carboxymethyl cellulose(CMC-Na)was selected as soil amendment. Field experiments were conducted. Five treatments, CK(0 kg/hm²), T1(CMC-Na 100 kg/hm²), T2(CMC-Na 500 kg/hm²), T3(CMC-Na 1 000 kg/hm²)and T4(CMC-Na 2 000 kg/hm²), were designed to investigate their effects on soil water content, soil electric conductivity and soil nutrient. The results were shown as follows: 1)Applying CMC-Na had a great effect on soil water content and increased soil water content to 21. 3%-120. 9% when soil water content was less than 16. 3%. While there were no significant differences among treantments when soil water content was more than 16. 3%. 2)The soil electric conductivity gradually decreased with millet growing season in new cultivating farmland, but the decreasing trends were different among treatments. The main influence factor of soil electric conductivity was soil nutrient. 3)Applying CMC-Na mainly affected soil available nutrient more than the total nitrogen, total phosphorus and total potassium, and raised available phosphorus and potassium. The lower amount of CMC-Na application in T1 and T2 improved nitrate in soil and the higher amount of CMC-Na application of T3 and T4 reduced nitrate in soil. The CMC-Na application no effect on soil pH. 4)The millet yield were respectively increased by 6. 4% and 7. 5% in T1 and T2 and it was reduced yield in T3. In conclusion, the CMC-Na application increased soil water contend, promoted plant nutrient absorption and raised millet yield. It can be used as soil amendment for new cultivating farmland in Loess Plateau and the recommended application rate is 100 kg/hm².