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研究包膜型控释肥料在不同温度和不同土壤水分含量(从田间持水量到较低的风干土壤水平)条件下的养分释放。并将土壤含水量换算成水蒸气压,再将土壤中控释肥料包膜内外的水蒸气压差换算成纯水蒸气压条件下的温度,代入ArataKobayashi改进模型,比较释放率的预测值与实测值,分析了土壤水分与释放速率的关系。结果表明,当土壤水分含量30%(田间持水量的100%),0.42MPa的土壤水势包膜型控释肥料的养分释放速率的实测值与预测值一致,低于这一水分含量的土壤,释放速率下降。土壤含水量2.3%(相当田间持水量的7.7%),土壤水势在100MPa以上时,包膜型控释肥料的养分完全不能释放。在低水分含量下的土壤渗透势对包膜型控释肥料养分释放的影响较小,影响养分释放的主要因子是基质势。
The release of nutrients from coated controlled release fertilizers under different temperatures and different soil moisture contents (from field to lower soil level) was studied. The water vapor pressure inside and outside the controlled release fertilizer capsule in the soil was converted into the temperature under pure water vapor pressure and put into ArataKobayashi improved model to compare the predicted value of the release rate with the measured Values, the relationship between soil moisture and release rate was analyzed. The results showed that when the soil moisture content was 30% (field water content of 100%), 0.42MPa soil water potential of coated controlled release fertilizer nutrient release rate of the measured values and predicted values ?? below the soil moisture content, Release rate decreased. Soil moisture content of 2.3% (equivalent to 7.7% of water holding capacity), soil water potential of 100MPa or more, the coated controlled release fertilizer nutrients can not be released. The soil osmotic potential at low water content has little effect on the release of nutrients from the coated controlled release fertilizers. The main factor affecting nutrient release is the matrix potential.