CORVALLIS, Ore. – Adding organic matter is the best way to improve nearly all kinds of soils. If you're unsure if your soil needs amendments, take note if it dries and cracks in summer, drains slowly or is difficult to dig whether wet or dry. Do your rhododendrons and other shrubs wilt in hot weather, even with added water?
Adding organic materials improves the ability of sandy soils to hold nutrients and water. For clay soil, organic additions improve drainage and aeration and help the soil dry out and warm up more quickly in the spring.
Good organic amendments for garden soils include wood by-products such as sawdust and bark mulch, peat moss, rotted manure, grass or wheat straw and compost. Inorganic amendments include pumice, perlite, vermiculite and sand.
Any composted material that has been reduced to humus is a good soil amendment. However, the breakdown of high-carbon organic matter in cattle and horse manure can take years. To speed the process, mix additional nitrogen into your garden – at least six pounds of ammonium nitrate or 10 pounds of ammonium sulfate per inch of organic matter, applied over a 1,000-square-foot area.
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http://extension.oregonstate.edu/news/story.php?S_No=1076&storyType=garden
Contacts:
Judy Scott, (541) 737-1386?
Gail Langellotto, (541) 737-5175
