保水剂对粘质潮土团聚体分布、稳定性及玉米养分积累的影响

通过玉米盆栽试验,研究了4种不同类型保水剂对粘质潮土团聚体分布、稳定性和玉米养分积累及吸收利用的影响。结果表明:保水剂保水效果在玉米生长中后期显现,收获期各处理土壤含水量比对照提高21.45%~65.09%;通过计算5种土壤团聚体特征参数并分析其与土壤粒径组成的相关性发现,聚丙烯酸钠(WT_1)与自制有机肥型保水剂(OSC)的土壤水稳性大团聚体数量(R_(0.25))比施肥处理(T_1)显著提高72.40%和58.00%,平均重量直径(MWD)和几何平均直径(GMD)较T_1分别显著提高45.91%,67.89%和57.34%,64.11%,土壤不稳定团粒指数(E_(LT))显著降低18.51%和14.83%;各保水剂处理使分形维数(D)降低0.10%~2.64%;GMD与土壤各级颗粒含量均呈极显著相关(p0.01),较其他参数可更准确的反应土壤团聚体分布及稳定性;聚丙酰胺型保水剂(AS)和OSC对于土壤氮素的保持和促进氮素转化效果更好,籽粒含氮量比T_1分别显著上升10.37%和15.67%。OSC对提高土壤团聚体和促进养分吸收利用均具有显著效果,这对进一步研制复合功能保水剂提供了参考。

Effects of Different Kinds of Super Absorbent Polymers on Distribution and Stability of Clay Soil Aggregate and Nutrient Accumulation by Maize

The effects of four different kinds of super absorbent polymers (SAP) on clay soil aggregates and nutrient accumulation by maize were studied through pot experiments.The results showed that the effects of SAP on water-holding capacity appeared in the middle to late stage of maize growth.Compared with the treatment of no absorbent application (T1),the water contents of soil were increased by 21.45％ to 65.09％ at harvest time.Five soil aggregate characteristic parameters were calculated,and their correlations with soil particle size composition were analyzed.The amount of water-stable macro-aggregates (R0.25) of the soil treated with Poly (acrylate sodium) (WT1),and organic fertilizer and SAP compound (OSC) notably was increased by 72.40％ and 58.00％,respectively,compared with the control (T1).Mean weight diameter (MWD) and geometric mean diameter (GMD) of the soil treated with the two above-mentioned SAP was significantly increased,i.e.by 45.91％ and 67.89％,and by 57.34％ and 64.11％,respectively,while the soil unstable aggregate index (ELT) was decreased by 18.51％ and 14.83％.In addition,the application of SAP could reduce fractal dimension (D) by 0.10％ to 2.64％.Correlation analysis showed that soil particles size distribution was extremely significantly correlated with GMD (p＜0.01),which could be the best quantitative index of soil texture.Acrylamide/potassium acrylate copolymer (AS) and OSC promoted the uptake and utilization of nitrogen nutrient by maize,and the nitrogen content of grains was significantly increased,i.e.by 10.37％ to 15.67％.The application of OSC could improve soil structure and nutrient absorption more efficiently.This research provides academic and instructive bases for developing soil amendments.