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为探讨各土地利用类型对土壤氮、磷、有机质等养分的拦蓄效果,对元谋干热河谷区那能小流域内草地、林地、坡耕地三种土地利用类型区雨季前后的土壤养分含量变化情况进行了分析。研究结果表明:①经过5个月的雨季,表层土壤(0—30 cm)中,草地和坡耕地全氮含量分别减少0.001、0.089 g/kg,林地全氮含量增加0.057 g/kg;草地与林地碱解氮含量分别增加10.466、1.305 mg/kg,坡耕地碱解氮含量减少25.833 mg/kg;林地与坡耕地全磷含量分别减少0.186、0.320 g/kg,草地全磷含量增加0.030 g/kg;草地与坡耕地速效磷含量分别减少1.540、2.186 mg/kg,林地速效磷含量增加2.161 mg/kg;林地与坡耕地有机质含量分别减少0.294、0.702百分点,草地有机质含量增加0.556百分点。②土壤全氮与碱解氮、全氮与有机质、有机质与碱解氮含量呈显著性相关,全磷与速效磷、有机质相关性不明显。③由于人为扰动,坡耕地雨季前后各土壤养分指标存在较大的差异性。
In order to investigate the effect of different land use types on the nutrient uptake of soil nitrogen, phosphorus and organic matter, the changes of soil nutrient contents before and after the rainy season in three land use types of grassland, forest land and sloping land in that area of the Nalngxia small watershed in Yuanmou dry-hot valley were studied Analyzed. The results showed that: ① After five months of rainy season, the contents of total nitrogen in grassland and sloping land decreased by 0.001 and 0.089 g / kg respectively in the topsoil (0-30 cm) and increased by 0.057 g / kg in the forestland; The content of nitrogen in forest land increased by 10.466 and 1.305 mg / kg respectively, and the content of available nitrogen in slope farmland decreased by 25.833 mg / kg. The content of total phosphorus in forest land and slope land decreased by 0.186 and 0.320 g / kg, kg. The contents of available P in grassland and sloping land decreased by 1.540 and 2.186 mg / kg, respectively. The content of available phosphorus in woodland increased by 2.161 mg / kg. The contents of organic matter in woodland and sloping land decreased by 0.294 and 0.702 percentage points respectively, while the organic matter content in grassland increased by 0.556 percentage points. ② There was a significant correlation between soil total nitrogen and available nitrogen, total nitrogen and organic matter, organic matter and available nitrogen. The correlation between total phosphorus, available phosphorus and organic matter was insignificant. ③ Because of man-made disturbances, there is a big difference in soil nutrient index before and after rainy season.