青海海西荒漠半荒漠草地氮硫的季节变化及盈缺分析

在春季(3月中旬),夏季(7月中旬)和秋季(11月中旬)对青海海西地区荒漠半荒漠草地中的土壤、可食牧草和绵羊的血清、瘤胃液、被毛等进行了检测分析。结果表明:7月份的土壤全氮为(0.33±0.10)%,土壤有效硫为(42.65±8.57)mg/kg,均分别显著高于3月份土壤全氮(0.15±0.04)%、土壤有效硫(20.00±3.02)mg/kg和11月份土壤全氮(0.07±0.03)%、土壤有效硫(37.85±7.91)mg/kg。三季都能满足植物生长的基本需要;可食牧草中的全氮和全硫在7月份时最高,春季和秋季,牧草含量远不能满足绵羊生长的需要;血清中的氮、硫在3月份、7月份和11月份表现出相同的变化趋势,均为7月份>11月份>3月份。3月份血清白蛋白的含量(33.92±9.77)g/L显著低于7月份(53.11±10.59)g/L和11月份(53.53±7.74)g/L,三季含量均低于绵羊血清白蛋白正常含量;瘤胃液氮与牧草氮含量和血清白蛋白的变化规律一致。

Seasonal dynamic of nitrogen and sulfur of desert and semi-desert grasslands in Haixi of Qinghai

The contents of nitrogen and sulfur in soil,forage and sheep(samples from plasma,rumen fluid,wool and urine) of the semi-desert grassland in western Qinghai were studied.The results showed that: The contents of total nitrogen and available sulfur in soil in July were(0.33± 0.10) and(42.65±8.57)mg/kg,and were significantly higher than that in March(0.15±0.04)% and(20.00± 3.02)mg/kg and November(0.07±(0.03))% and(37.85±7.91)mg/kg,which could meet the grass demand in growth season.The highest contents of total nitrogen and sulfur in edible grass both in July and March were not enough for the healthy lamb growth.The concentrations of total nitrogen and sulfur in sheep plasma showed the tendency that they were highest in July and followed by that in November and then in March.The white protein in plasma in March(33.92±9.77) g/L was significantly lower than that in July(53.11± 10.59) g/L and November(53.53±7.74) g/L,and they were below the normal range.The variation patterns of nitrogen contents in rumen fluid and grass showed same tendency with that of white protein in plasma.