滴灌专用肥中磷素在3种土壤—棉花系统中的运移

基于同位素示踪技术,将32P标记的滴灌专用肥滴入3种不同类型的土壤,应用储磷屏扫描影像技术研究磷素在土壤中的运移情况,同时应用超低本底闪烁仪测定土壤和棉株32 P放射性活度。结果表明,各处理磷素在3种土壤中的运移距离均在10cm以内。灰漠土+滴灌专用肥处理的运移距离高于其他处理,并且施用滴灌专用肥后的运移距离为灰漠土(8.49cm)>草甸土(5.48cm)>红壤(3.65cm)。滴灌专用肥在不同土壤中的运移距离存在显著差异;棉株对磷素的吸收情况在不同土壤中也存在显著差异;棉株和土壤速效磷中32P放射性活度占总标记量的比例在各处理间存在显著差异。从运移距离、棉株生长等方面看,滴灌专用肥并不适合在红壤中施用,在新疆两种石灰性土壤中的施用也有差异,灰漠土中植物吸收的32 P放射性活度明显高于草甸土,而草甸土速效磷中32P放射性活度又明显高于灰漠土,两种土壤植物吸收的32 P放射性活度比例与土壤速效磷中残留的32P放射性活度比例之和相差不大。从植物对磷素的吸收而言,灰漠土中施用滴灌专用肥明显好于草甸土,这可能是由于草甸土本身的养分指标高于灰漠土,施用同样量的滴灌专用肥可能对作物的吸收以及土壤养分的转化产生影响,所以建议在新疆各类型土壤中施用滴灌专用肥前先测定土壤的基本理化指标,再根据实际情况施用各种肥料。

Phosphorus Migration of Drip irrigation Special Fertilizer in Three Types of Soil cotton Systems

Based on the isotope tracer technique, ³²P labeled drip irrigation special fertilizer was dripped into three different soils. We studied the migration of phosphorus in soil using storage phosphor system, and determined the ³²P activity in soils and plants using liquid scintillation counter. The results showed that the migration distance of phosphorus in three soils was within 10cm. The decreasing order of the migration distance of the special fertilizer was grey desert soil (8.49 cm) > meadow soil (5.48 cm)> red soil (3.65 cm). There were significant differences in migration distance of drip irrigation special fertilizer in different soils. The phosphorus absorption of cotton also significantly varied in different soils. The percentage of ³²P activity in cotton and soil available phosphorus had significant difference in different treatments. In this study, special fertilizer was not suitable for application in red soil according to the migration distance, cotton growth and other aspects, but special fertilizer showed differences between the two kinds of calcareous soils. The activity of ³²P labeled phosphorus absorbed by cotton in grey desert soil was higher than that in meadow soil, but the ³²P activity of available phosphorus in meadow soil was higher than that in grey desert soil. The sum of ³²P activity of cotton and soil available phosphorus in two calcareous soils had no difference. For phosphorus absorption of cotton, the application of drip irrigation special fertilizer was better in grey desert soil than in meadow soil, which might be due to the higher nutrient indexes of meadow soil. Using the same amount of special fertilizer in meadow soil might affect plant absorption and the transformation of soil nutrient. It was recommended that the application of drip irrigation special fertilizer in various soil types of Xinjiang should be conducted based on soil physicochemical indexes and actual situation.