| Study on the dynamic changes of net primary productivity of cultivated land in pasturing-farming region —— A case over Yuyang district |
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| DOI：10.7606/j.issn.1000-7601.2007.01.04 |
| Key Words: pasturing-far ming region Yuyang district cultivated land NPP dynamic research |
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| Abstract: |
| Based on the grain yield of Yuyang district from1984 to 2003 the author chosen a suitable model to esti mate net pri mary productivity of cultivatedland of different region to research the relation bet ween ecological environment and NPP of cultivatedland ．The results shown as follows ：（1） The total amount of NPP of cultivatedland in Yuyang district generally increased during 1984～2003．Its total amount has grown from 21．94×104t／a in 1984 to 57．98×104t／a in 2003．The annual increasing rate was 5．24％．（2） The unit area amount of NPP of cultivatedlandin the north was not only much more than that in the south but also increased fast during 1984～2001．At the same ti me the unit area amount of NPP of cultivatedland changedlittle in the south ．（3） During 1984～2001 the unit area amount of NPP of cultivated land in urban was the highest and that in suburb fellowed it ．The total amount of NPP of cultivated land in urban suburb and outer suburb of Yuyang district all increased generally and that in outer suburbfluctuatedlargestly ．（4）Theincrease of the NPP of cultivatedland was partly because of increasinginvestition in agriculture but mainly because of ecological environment i mprovement of Yuyang district． |