有声读物: Crops and Methods for Soil Improvement

This book is not a technical treatise and is designed only to point out the plain, every-day facts in the natural scheme of making and keeping soils productive. It is concerned with the crops, methods, and fertilizers that favor the soil. The viewpoint, all the time, is that of the practical man who wants cash compensation for the intelligent care he gives to his land...Experiment stations and practical farmers have developed a dependable science within recent years, and there is no jarring of observed facts when we get hold of the simple philosophy of it all. Summary from the Introduction