自然肥力

土地经济肥力是人工肥力和自然肥力的统一体；

Economic fertility of soil is a combined formation of artificial and natural fertility .

森林土壤肥力以维持和恢复自然肥力为主，人工施肥为输。

Forest soil fertility mainly relies on maintaining and resuming natural fertility and combines with artificially applying fertilizer .

结果表明：群落土壤呈微酸性，自然肥力较低；

The results showed that soil appears a little acidic and low-fertility .

有机肥贡献份额为21.6%；土壤自然肥力贡献份额平均为19.0%。

The contribution quotient of chemical fertilizer , organic manure and soil natural fertility to crop yield was 50.5 % , 21.6 % and 19.0 % respectively .

毛竹纯林随经营期的延长，其土壤的自然肥力呈下降趋势，这是毛竹纯林的生长特性和经营方式决定的。

As the management term of pure bamboo stands prolonged the natural soil fertility declined , which resulted from the growth characteristics of pure bamboo forest and the management methods .

土壤退化过程总是从环境劣化开始，进而使土壤剖面形态毁损和土质变坏，并逐步使自然肥力消失。

The initial stage of soil deterioration is from the process of soil environment worsening with destruction of soil genetic horizon and decline of soil characters and soil fertility vanishing gradually at last .

吉林省土壤质量等级与粮食单产水平的对比分析结果表明：受自然因素及人为因素双重影响，粮食产量由土壤自然肥力、种植结构以及投入水平等因素共同制约决定。

Compared soil quality rating with unit level of grain in Jilin Province , it leads to the results that : with the impact of natural and human factors , grain production is decided jointly by the natural soil fertility , planting structure and input level factors .