Trends of basic soil productivity in paddy soil under long-term fertilization in China
[Objectives] The paddy rice system shows a great stability to climate and soil basic fertility which makes a great contribution to rice yield , so soil basic fertility represents a key contributor for high and stable rice yield.Therefore, investigating changing trends of paddy soil basic fertility in different regions under long -term fertilization can provide scientific basis not only for sustainable rice production but also for assessing and proposing proper fertilization strategy .[Methods] An experiment was designed to include two treatments , CK ( no fertilizer ) and NPK ( conventional fertilization ) .The rice yield under the CK represents soil basic fertility , and the proportion of the crop yield under the CK to that under the NPK represents soil basic fertility contribution .Seven long-term field experiments in paddy crop systems ( rice-rice , and rice-wheat rotation ) were selected to investigate dynamic trends in soil basic fertility and its contribution , and to examine relationships between soil basic fertility contribution and rice yield or other indicators .[Results] In general , the rice yields under CK remain constant with a mean change rate of-0.3 kg/( hm2 · a) only.Soil basic fertility trends show differences among paddy soil types , and soil basic fertility levels show a declining trend for reddish paddy soils and remain constant for purple paddy soils . Under CK, both the late-rice and single-rice yields show increasing trends with rates of 1.6 and 29.2 kg/(hm2· a), respectively, while the early-rice yields shows a declining trend with a rate of 20.0 kg/( hm2 · a).The declining rates of rice yields in the CK treatment are highest at Baisha (BS) and Wangcheng (WangC) sites, up to 47-82 kg/(hm2· a).Those of early-rice at Nanchang (NC) site and single-rice at the Wuchang (WuC) and Suining (SN) sites show increasing trends with the rates of 44-81 kg/(hm2· a).On average, the rice soil basic fertility contribution ranges from 42% to 68%, with a mean value of 59.7%.The contribution percentages are 55.1%, 67.1% and 54.9% for early-rice, late-rice and single-rice, respectively. Soil basic fertility is significantly positively correlated with sustainable yield index (SYI) in the CK treatment (r=0.655, n=13).The mean annual rice yield is 5100 kg/hm2 under the NPK treatment , which is significantly higher than that under the CK treatment (2911 kg/hm2 ) in the seven sites.The contribution of the NPK fertilization to rice yield is 40.3%.[Conclusions] Under no fertilizer , the yields show stable or increasing trends for late-rice and single-rice, but show a declining trend for early-rice especially in red paddy soils .The rice yields are most stable for the purple paddy soils.Under the fertilization, the rice yields are stable across all the sites.From a long-term view, increasing soil basic fertility can be effective in elevating rice yield sustainability .
long-term fertilizationsoil basic fertilitysustainable yield index
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万方数据
维普
