oligotrophic conditions是什么意思

用法例句

In 1993,the mixed planting test of Pinus massoniana was done in infertile,dry and hot areas with the elevation of 1 000 ～ 1 500 m located at north of Honghe prefecture.

９９３年于红河州偏北部海拔１０００～１５００ｍ造林困难的贫瘠干热地带进行混交造林试验。

Soil erosion is a main factor of soil degradation of purple soil sloping field in the Three Gorges reservoir area,and therefore it leads to impoverishment of soil nutrient.

土壤侵蚀是三峡库区紫色土坡地土壤退化及土壤养分贫瘠化的主因。

At present,there are kinds of different impoverishment to farmland soil in Fujian whose organic matter is not high especially the orchard soil,nitrogen and potassium is most serious,phosphorus and available phosphorus is apparently impoverished in some low Fertilizer soil such as the new fruit soil,while available potassium sees no impoverishment.

目前福建省山地丘陵地区农地土壤存在不同程度退化,有机质普遍不高,利用类型为果园的土壤有机质多呈贫瘠化;全氮和全钾贫瘠化最为严重;全磷、有效磷在熟化度较低的土壤如新果园土壤呈明显贫瘠化,有效钾在闽北闽东南都未呈贫瘠化。

Putting soil micro algae which were native to fertile soil into sterile soil, and then culturing them under dark and light conditions separately, the results showed: under dark condition, soil micro algae almost come into dormant state or dead in 30days; under light condition, micro algae increase at some degree in 30 days, and then breed rapidly.

将自然条件下肥沃土壤中的微藻接种到贫瘠土壤中 ,分别在黑暗和光照条件下进行培养 ,结果显示 :黑暗条件下的微藻在 30d内进入休眠状态或死亡 ;在光照条件下 ,微藻的数量在第 30d以后迅速增殖 ,随着藻类的生长 ,土壤pH值也发生了一定变化 ,且藻类数量的变化与土壤有机质和土壤有效磷的变化呈极显著相关 ,说明土壤微藻能改善贫瘠土壤的微生态环境和提高土壤肥力 ,上述结果可为藻类用于农业生产和沙漠治理等提供理论依

The paper fristly compared the fertile soil with the incinerated sterile soil on the number of micro-algae , soil pH value , soil organic matter soil available phosphorus and soil nitrogen.

本文首先对肥沃土壤与经高温焚烧后的贫瘠土壤中的微藻数量、土壤pH值、有机质含量、有效磷含量和全氮量进行比较研究，然后将包含微藻的绿化苗圃地肥土按不同比例接种进入贫瘠土样中，分别在光照条件和黑暗条件下进行培养，在0天、30天、60天和90天分别检测以上指标，比较有光条件和无光条件下，即有藻条件和无藻条件下贫瘠土样所发生的变化，并分别对微藻数量的变化与土壤pH值、有机质含量、有效磷含量和全氮量的变化之间做相关性分析，以评估肥沃土壤中的微藻接种进入贫瘠土壤后的生长情况以及对贫瘠土壤的改良作用。

Study of Soil Nutrient Depletion of Chongqing Based on GIS;

基于GIS重庆市土壤养分贫瘠化研究

Soil nutrients depletion trend under 4 commercial forests (Cunninghamia lanceilata, Phyllostachy pubescens, Camellia sinensis  and fruit forest) were measured by comparison with broad leaved forest.

以常绿阔叶林为参比 ,分析了红壤上人工杉木林、毛竹林、茶园和果林 4类商品林地土壤养分贫瘠化状况。