It was found that soil erosion resistance increased with the number of plant roots, though no consistent quantitative functional relationship was observed between them.
研究发现，土壤抗侵蚀性随着植物根系数量的增加而提高，但未有一致的定量函数关系。
2
The relationship between nitrate fertilizer application and cultivated conditions such as soil fertility, preceding crop, plant density and irrigation etc.
本文对马铃薯经济施肥量与土壤、前作、密度、灌溉等栽培条件的关系进行了定量研究。
3
The relationship between environmental factors (climate and soil) and plant life form gradient was analysed by doub sieving progressive regression method, and mathematical models were set up.