Details on an exhaustive study of 35 manure additives at Purdue University are available from the National Pork Board in a 200-page book – it's also available on the Internet. The study was part of the ongoing, $5-million Odor Solutions Initiative.

Vendors voluntarily submitted their products to the study. Each additive was evaluated during three testing periods that ran for 42 days each. Measurements were taken of odor, ammonia and hydrogen sulfide gas emissions, plus fertilizer value of manure receiving that treatment in the study. Each product's results were compared with untreated manure.

The summary of each product includes the method and rate of application for manure-storage pits, how to calculate the amount to be applied, current retail product price and the manufacturer's or distributor's contact information.

You can find the complete, 200-page report on the Internet at in the " For Producers" section under " OSI Results: Manure Pit Additive Testing" .

The book, containing the identical 200 pages, is $15 per copy postage-paid (check, VISA or MasterCard) from the Ordering Department, National Pork Board, P.O. Box 10383, Des Moines, IA 50316. Telephone: (800) 456-7675.