论文部分内容阅读
以东南丘陵区的联合梯田土壤为研究对象,探讨不同海拔土壤有机质(SOM)、碱解氮(SAN)、有效磷(SAP)、速效钾(SAK)含量及其化学计量比的分布特征.结果表明:在海拔100~299 m(Ⅰ)、300~499 m(Ⅱ)、500~699 m(Ⅲ)、700~899 m(Ⅳ)、900 m以上(Ⅴ)5个梯度,SOM含量在海拔Ⅰ~Ⅳ基本稳定,在海拔Ⅴ显著增加;SAN含量随着海拔的升高略有增加趋势;SAP和SAK含量在海拔Ⅰ较低,从海拔Ⅱ到Ⅴ呈下降趋势.SOM、SAN含量在各海拔梯度肥力总体较高,SAP和SAK肥力中等偏上(除Ⅴ外);SAN与SAP含量比无明显变化规律,SAN与SAK含量比和SAP与SAK含量比随着海拔的升高呈“Ⅴ”字型变化.此外,高海拔区(Ⅳ和Ⅴ)土壤SAN与SAP含量比较高,表明联合梯田土壤在高海拔区存在一定的磷限制,需加强施肥指导,适当增施磷肥.
This paper studied the distribution characteristics of soil organic matter (SOM), available nitrogen (SAN), available phosphorus (P), available potassium (SAK) and their stoichiometric ratios in the southeast hilly region of the United States. The results showed that there were five gradients (Ⅴ) of 300 ~ 499 m (Ⅱ), 500 ~ 699 m (Ⅲ), 700 ~ 899 m Ⅰ ~ Ⅳ were basically stable and significantly increased at Ⅴ elevation; the content of SAN increased slightly with the elevation; the contents of SAP and SAK were lower at elevation Ⅰ and decreased from Ⅱ to Ⅴ; The fertility of altitudinal gradient was generally high, and the fertility of SAP and SAK was moderately high (except Ⅴ). There was no obvious change in the ratio of SAN to SAP, and the ratio of SAN to SAK and the ratio of SAP to SAK were increased with the elevation In addition, the contents of SAN and SAP in the high altitude areas (Ⅳ and Ⅴ) were relatively high, which indicated that the combined terraced soils had certain phosphorus limitation in the high altitude areas, and the fertilization guidance should be strengthened and the phosphorus fertilizer added appropriately.