If you're looking for specifics on conservation, check out the Conservation Technology Information Center (CTIC). They've got a library of information, and it's on sale.
Here are just a few of their many titles that can be found at www.conservationinformation.org or call 765- 494-9555:
No-Till Farming Systems with CD, $18
Conservation Tillage Systems and Management, $15
No Tillage: the Relationship Between No-Tillage, Crop Residues, Plants and Soil Nutrition, $15