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Experiment Station Work, XXIX

Allerton Seward CushmanC. F. LangworthyCharles Pinckney HartleyDavid Ernest LantzEdwin Harrison WebsterGeorge Lemon ClothierKarl Frederic KellermanMerton Benway WaitePeter Henry RolfsPhilip Lightfoot WormeleyRichard H. WoodTheodore Sherman PalmerThomas ShawWilliam Allen OrtonWilliam Jasper SpillmanWilliam Renwick BeattieHenry OldysT. Ralph RobinsonRobert White Williams

其他書名	Injury by Smoke and Gases, Tomato Growing, Fertilizer Mixtures, Influence of Feed on Milk, Flint Varieties of Corn, Protecting Cows from Flies, Buying and Judging Seed Corn, Experiments with Turkeys, Tobacco Seed, Mineral Matter for Chickens, Cowpea Seed, Brooder Heat, Treating Seed Oats for Smut, American Camembert Cheese, Potato Culture, Swelling in Canned Peas
出版	U.S. Department of Agriculture, 1905
URL	http://books.google.com.hk/books?id=toU6AQAAMAAJ&hl=&source=gbs_api
EBook	FULL_PUBLIC_DOMAIN

註釋To build up and maintain fertility in the soil, feed a large part of the crops and return the manure to the land. If manure is not available, plow under crops grown for the purpose. Plow deep (but do not subsoil). Grow leguminous crops for the nitrogen they add to the soil. Commercial fertilizers and lime may be important means of improving the soil, but the fertilizer requirements of different soils and different crops in different seasons are so little understood that we are not yet in a position to make positive recommendations that are of a general application.