1. 本来就低的土壤中速效磷,氮迅速通过淋溶和挥发损失。
The soils are inherently low in available phosphorus, and nitrogen is quickly lost through leaching and volatilisation.
2. 以中国科学院海伦农业生态实验站长期定位试验为平台,研究了不同土地利用和施肥方式对土壤酶活性和相关肥力因子的影响,结果表明,种植苜蓿和土地休闲两种方式与裸地相比脲酶、转化酶、磷酸酶、过氧化氢酶活性、土壤全碳、全氮含量和碱解氮、速效磷、速效钾含量均显著增加。
The results showed that soil enzymes activity, TC, TN alkaline hydrolytic nitrogen, available P and available K in both clover land and fallow land significantly increased compared with bald land, in which urease activity increased by 24.5% and 25.0%, invertase activity 18.4% and 18.9%, phosphatase activity 54.6% and 50.4% and catalase activity 8.52% and 59.3%, TC and TN increased by 13.8%, 13.0% and 36.8%, 33.7%, respectively.
3. 有效磷在城区林业土壤中富集,在城郊天然林土壤中明显缺乏,土壤速效钾富集。
Soil available phosphorus was enriched in incity forest soil but lacking in suburban natural forest...
4. 不同播种方式下土壤有机质、碱解氮、速效磷含量在0-40cm各土层内呈现随着土层深度的增加而降低的趋势,均以0-10 cm土层土壤含量为最大;同行混播和隔行混播草地速效钾呈现降低的变化趋势,单播无芒雀麦草地则呈现先降后增再降的变化趋势,以0-10 cm和20-30 cm土层土壤含量为最大,均为80,并与其它土层间达到极显著差异;pH则呈现出增加趋势。0-40cm土层土壤平均值来看以隔行混播草地土壤有机质、碱解氮含量最高;速效磷、速效钾以单播无芒雀麦草地含量最高;同行混播草地pH最大。