中国科学院新疆生态与地理研究所机构知识库

为探究土壤改良剂对风沙土性质特别是力学性质及植物生长的影响， 本研究选取羧甲基纤维素钠、磷石膏和生物炭三种常用的土壤改良剂与沙漠边缘的风沙土混合， 进行盆栽实验种植棉花， 测定植物生长指标， 并在实验前后测定土壤理化及力学指标， 同时对土壤理化指标和植物生长指标进行主成分分析及加权求和计算， 建立综合改良评价体系。 得到如下结论：土壤理化性质： （1） 在相同灌水量条件下， 改良处理后风沙土容重均比对照小， 孔隙度均比对照大， 且各改良处理的容重均随着改良剂添加量的增加而降低， 孔隙度均随着改良剂添加量的增加而增大， 灌水量对土壤容重和孔隙度影响都不大。 三组处理中对风沙土容重和孔隙度影响最大的是生物炭处理， 与空白对照相比， C3 处理容重降低了 12.06%， 孔隙度增加了 39.03%。 （2） 土壤改良剂能使强碱性的风沙土碱性变弱， 但不同土壤改良剂对风沙土电导率的影响不同。无论灌水量高低， 三组改良剂处理的风沙土 pH 均小于对照处理， 且 pH 均随改良剂添加量的增大而减小， 而灌水量对风沙土 pH 值的影响均为高灌水量条件下pH 更小。 对风沙土 pH 和电导率影响最大的是磷石膏处理， BG3 处理风沙土 pH降低至 7.79， BD2 处理风沙土电导率增幅高达 147.67%。 （3） 土壤改良剂能使几乎无肥力的风沙土肥力增强， 在相同灌水量条件下， 改良剂处理使风沙土有机质及养分含量大部分有所增加， 其中有机质、 全氮、 全磷、 速效磷及速效钾含量均随着改良剂添加量的增加而增大， 全钾含量变化不大。 不同灌水量处理下风沙土有机质及养分含量变化不大。 对风沙土有机质、 全氮、 速效磷和速效钾影响最明显的是生物炭处理， 增幅高达 855.78%、 621.64%、 330.43%及 46.95%。 而对风沙土全磷影响最大的是磷石膏处理， 增幅高达 182.31%。土壤力学性质： （1） 无论含水量高低， 三种改良处理的风沙土内聚力均大于对照， 且羧甲基纤维素钠>磷石膏>生物炭， 但改良处理与对照相比对内摩擦角无显著影响。 随着改良剂添加量的增加， 内聚力随之增大， 对其进行回归分析，也都得到了较好的拟合效果， 但内摩擦角的变化不明显。 同一添加量下， 低水处理下风沙土内聚力和内摩擦角均大于高水处理， 但大多数处理间差异不显著（p>0.05） 。 土壤改良剂及含水量主要是通过增大内聚力来提高土壤抗剪强度，但各因素间交互作用均对内聚力无显著影响； 其中施用羧甲基纤维素钠对风沙土抗剪强度改良效果最佳，AD3 的风沙土内聚力与对照相比增幅高达 246.18%。（2）各改良处理的风沙土压缩系数均大于对照土体， 对照风沙土为低压缩性土， 改良处理后部分变为中压缩性土， 且随着土壤改良剂添加量的增加， 风沙土压缩性能逐渐增强， 但显著性水平随改良剂的不同而发生变化， 同时含水量对压缩系数的影响不大。 对压缩系数影响最大的是羧甲基纤维素处理， AG3 处理与对照相比压缩系数增幅高达 83.89%。植物生长指标： （1） 土壤改良剂对棉花出苗率影响不大， 而灌水量对棉花出苗率有较大影响， 高灌水量下棉花出苗率均大于低灌水量下。 （2） 土壤改良剂在棉花生长初期对株高影响不大， 主要在生长中后期影响植株生长。 改良剂处理后棉花的株高及基茎均大于对照处理， 且随着改良剂添加量的增大而提高， 在高含水量时改良剂对植物生长的影响尤为显著。 灌水量对棉花生长有极大的影响， 低灌水量严重抑制了植物生长。 生物炭处理对棉花生长状况影响最大， 棉花长势最好， 与对照相比， 株高涨幅高达 78.73%， 基茎涨幅高达 36%。 （3） 三种改良剂处理后棉花生物量均大于对照处理， 三种改良剂对棉花生物量的增长率由大到小为生物炭处理>磷石膏处理>羧甲基纤维素钠处理， 且随着土壤改良剂添加量的增大， 棉花生物量基本呈逐渐增加趋势， C3 处理生物量比对照提高了386.93%。 同时灌水量对生物量有显著的影响， 低灌水量处理下的棉花生物量明显小于高灌水量处理。生物量对土壤改良剂和灌水量的响应规律与株高基茎的变化一致。综合改良体系： 由综合评价方程计算得出， 无论含水量高低， 生物炭处理综合得分最高， 其次为磷石膏处理， 羧甲基纤维素钠处理得分最低， 高灌水量下改良处理综合得分均大于低灌水量下， 在高灌水量下综合得分进行排序为 CG3>CG2> CG1> BG3> BG2> AG3> BG1> AG2> AG1， 其中施加生物炭 45 g/kg 处理的改良效果最好。

In order to explore the influence of soil amendment on sandy soil properties andplant growth, especially mechanical properties, three soil amendments includingsodium carboxymethylcellulose, phosphogypsum and biochar were mixed with sandysoil and potted for cotton cultivation. The indexes of plant growth were determined,and the physical and chemical indexes of soil were determined before and after theexperiment. At the same time, principal component analysis and weighted summationcalculation were applied to establish the comprehensive improvement evaluationsystem based on soil physical and chemical indicators and plant growth indicators.Theresults were as follows in conclusion:Physical and chemical property： soil amendment can make compacted sandy soilbecome loose and porous, soil permeability and anti-erosion ability. Under the sameirrigation condition, the bulk density of sandy soil is smaller than that of CK, and theporosity is larger than that of CK. The bulk density of the three treatments decreaseswith the increasing amount of amendment, and the porosity increases with theaddition of amendment Increasing, the amount of irrigation on soil bulk density andporosity have little effect. Compared with CK, bulk density of C3 treatment decreasedby 12.06% and porosity increased by 39.03%, which greatly improved the soil bulkdensity and porosity, which greatly improved the soil structure.Soil amendment canweaken the alkalinity of sandy soil, but the effect of different soil amendment on theconductivity of sandy soil is different. Under the same irrigation condition, the pH ofsand soil treated with three amendments was lower than that of CK, and the pHdecreased with the increase of added amount. The effect of irrigation amount on pH ofsandy soil was that pH was lower under high irrigation condition, phosphogypsumwas the most influential factor on pH and conductivity of sandy soil, pH of BG3decreased to 7.79, conductivity of BD2 increased by 147.67% , Making the pH of thesoil more suitable for plant growth, and increasing the amount of exchangeable ions.Soil amendment can make almost no fertility of sandy soil fertility enhancement,under the same irrigation conditions, the three groups of amendment treatment ofsandy soil organic matter and nutrient content are mostly improved soil fertility canbe improved, including organic matter, total nitrogen, The content of total phosphorus,available phosphorus and available potassium increased with the increase of soilamendment, while the content of total potassium did not change much. The effect ofirrigation on soil organic matter and nutrient content was insignificant. The greatestimpact on soil organic matter, total nitrogen, available phosphorus and availablepotassium is biochar, an increase of 855.78%, 621.64%, 330.43% and 46.95%. Thegreatest impact on total soil phosphorus phosphogypsum treatment, an increase of upto 182.31%.Mechanical property： the soil amendment can significantly increase the cohesionof sand, the cohesion of the three amendments is larger than CK, and with theincrease of the amount of soil amendment, which cohesion compared with CKsequence of growth rate of sodium carboxymethyl cellulose> phosphogypsum>biochar. Under the conditions of low water, the cohesion of sandy soil with AD3 is24.47 kPa, which is 246.18% higher than that of CKD, and the cohesion of aeoliansandy with low water treatment is greater than that of high-water treatment. The typesof soil amendments have a significant effect on the internal friction angle, but thevariation law is not obvious. The addition amount of amendment has little effect onthe internal friction angle of aeolian sandy soil, and at the same time, the internalfriction angle of aeolian sandy soil with low water treatment slightly increases.Different types of soil amendments, additives and soil moisture mainly by increasingthe cohesion of sand to improve the shear strength. The sand used in this experimentis low compressibility soil. The compressibility of sand treated by three amendmentsis larger than that of CK. After the modification, some of sandy soil becomemesocompressive soil. With the increase of soil amendment, Compressiveperformance is gradually enhanced, water content has little effect on the compressionfactor. The greatest impact on the compression factor is carboxymethyl cellulose treatment, compared with CK ， AG3 treatment coefficient increased as much as83.89%.Plant growth index: soil amendments had little effect on the yield of cotton, andthe irrigation rate had a great influence on the yield of cotton, and the yield of cottonunder high irrigation was greater than that under low irrigation.Soil amendments inthe early stages of cotton plant height has little effect, mainly in the late growth of theplant growth. The plant height and diameter of cotton treated with amendment werehigher than that of CK, and increased with the increasing amount of amendment. Thetreatment of biochar had the greatest influence on the growth of cotton and the cottongrew best. Compared with Ck, the height of plant rose as high as 78.73% and thediameter increased as much as 36%. Under the condition of the same amendmentadded amount, the amount of irrigation had a great influence on the cotton growth,and the low irrigation amount severely inhibited the plant growth. The cotton biomassof the three amendments was higher than that of CK. The growth rate of threeamendments on cotton biomass was biochar> phosphogypsum> sodiumcarboxymethylcellulose, With the increase of soil amendment, the cotton biomassincreased gradually, and the biomass of C3 treatment increased by 386.93%. At thesame time, the amount of irrigation had a significant effect on the biomass, and thecotton biomass under the low irrigation was obviously less than the high irrigation.Comprehensive evaluation system: based on the comprehensive evaluationequation, the comprehensive score under high irrigation treatment was significantlygreater than that under low irrigation, and the comprehensive score was CG3> CG2>CG1> BG3> BG2> AG3> BG1> AG2> AG1. The application of 45 g/kg biochartreatment under high irrigation showed the highest comprehensive score, indicatingthat this treatment could be the best solution to improve the properties of sandy soiland plant growth.