Of the collection, one letter best sums up his views on the relationship between manure and freedom.

在他的文集中，有一封信很好地总结了他对于肥料与自由之间关系的看法。

youdao

With higher costs for nitrogen (a by product of the petroleum industry) and phosphorus more attention is being paid to the collection, distribution and resultant value of manure.

氮(石油工业副产品)和磷成本较高，因此对有机肥营养物的收集、分配及合成更受关注。

youdao