牛粪有机肥对植烟黄壤理化性质及持水能力的影响

  目的  探索牛粪有机肥对西南山区植烟黄壤的改良效果。  方法  采用土柱试验，探讨了不同牛粪有机肥用量对植烟黄壤理化性质、水力学参数、水分常数以及蒸发量的影响。  结果  结果显示:1）施入牛粪有机肥，可改变黄壤颗粒组成，明显增加有机质含量，缓解黄壤酸化，明显降低黄壤容重。2）随着牛粪有机肥用量增加，黄壤总空隙度明显增加，极微孔隙比例降低，中小微孔隙比例增加，大孔隙和土壤孔隙基本不变。3）随着牛粪有机肥用量的增加，黄壤残余含水率（θ_r）和进气值倒数（α）显著减小，而饱和含水率（θ_s）和饱和导水率（K_s）明显增大；黄壤田间持水量和易利用水基本不变，而凋萎系数和无效水显著降低，有效水大幅增加。  结论  牛粪有机肥可明显改善植烟黄壤的理化性质和持水性能，但由于牛粪有机肥具有肥效缓慢持久的特点，烟田当季施用易导致烤烟贪青晚熟，因此应在烤烟前季作物上施用效果更佳。 

Effect of cattle manure organic fertilizer on physicochemical properties and water-holding capacity of tobacco-planting yellow soil

In order to reveal the improvement effect of cattle manure organic fertilizer on tobacco-planting yellow soil in southwest mountainous area,soil column experiments were conducted to study the effect of application rate of cattle manure organic fertilizer on the physicochemical properties,hydraulic parameters,water constant and water evaporation capacity of tobacco-planting yellow soil.The results showed that the application of cattle manure organic fertilizer increased the particle content of the yellow soil ranged from 2 mm to 0.25 mm and < 0.002 mm,while reduced the particle content of 0.25-0.05 mm and 0.02-0.002 mm.The organic fertilizer had no obvious effect on particle content of 0.05-0.02 mm.With the increase of application of cattle manure,the bulk density and fine pore ratio of yellow soil decreased significantly from 1.273 g.cm^-3 and 54.72% in T0 treatment to 1.223 g.cm^-3 and 38.70% in T5 treatment,respectively.The organic matter,pH,total porosity,micro pore,small pore and medium pore ratio of yellow soil increased significantly from 22.53 g.kg^-1,6.22,51.96%,9.74%,11.36% and 7.14% in T0 treatment to 35.98 g.kg^-1,7.06,53.85%,17.14%,18.55% and 9.80% in T5 treatment,respectively.In terms of hydraulic parameters,with the increase of application of cattle manure,the residual water content (θr) and empirical parameters (α) of yellow soil decreased significantly from 0.231 cm^3.cm^-3 and 0.063 cm-1 in T0 treatment to 0.135 cm^3.cm^-3 and 0.028 cm-1 in T5 treatment,respectively.The saturated water content (θs) and saturated hydraulic conductivity (Ks) increased significantly from 0.485 cm^3.cm^-3 and 1.61 cm.h-1 in T0 treatment to 0.515 cm^3.cm^-3 and 3.03 cm.h-1 in T5 treatment,respectively,while the empirical parameters (n) remained basically unchanged.In terms of water constants,with the increase of application of cattle manure organic fertilizer,the wilting coefficient and unavailable water content of yellow soil decreased significantly from 0.261 cm^3.cm^-3 in T0 treatment to 0.192 cm^3.cm^-3 in T5 treatment.The effective water content and gravity water content decreased significantly from 0.083 and 0.141 cm^3.cm^-3 in T0 treatment to 0.152 and 0.171 cm^3.cm^-3 in T5 treatment,respectively.However,the field capacity and easily available water were basically unchanged.In the first 29 days of evaporation,the effect of cattle manure organic fertilizer on evaporation and water holding capacity of yellow soil was small,which became increasingly significant after 29 days of evaporation.The application of cattle manure organic fertilizer significantly improved the physicochemical properties and water holding capacity of tobacco planting yellow soil.However,the application of cattle manure in tobacco-planting field in the current season easily leads to the late maturity of flue-cured tobacco.Therefore,the cattle manure organic fertilizer should be applied in the for-rotating crop production.