From the yellowing pages of the first volume of Audels Gardeners and Growers Guide, published in 1928, comes this short piece on farmyard manure. We are fortunate to count this four-volume set from Audels among our extensive library of antique agricultural volumes.
It is always a question as to exactly what is referred to when the term barnyard or farm manure is used. It may be the stable manure of horses or cows, mixed barnyard manure, manure from hog pens etc., consisting of dung, urine, bedding, and also general farm waste. The manure heap, by the way, is no place for old tin cans, bottles, glass, and other similar waste material.
Naturally there is great variation in manure according to the animals it is made by, the feeding and bedding material, and the manner in which it is kept. Different analyses naturally shows different results and the tables here given serve only as a guide or index to the various kinds.
The smell of ammonia is common in horse stables. The urine is first to undergo bacterial changes by which ammonia is formed and passes into the air rapidly when spread over a wide surface at warm temperatures, particularly when nitrogenous compounds are present.