Agro-ecological assessment of manure from different farm animals by content of biogenic elements

D. Dermendzhieva1*, G. Kostadinova1, G. Petkov1, D. Dimov1, T. Dinev2, T. Penev1, Tch. Miteva1, J. Mitev1

1Department of Applied Ecology and Animal Hygiene, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria 2Department of Biochemistry, Microbiology and Physics, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 12 November 2016; accepted for publication 23 January 2017)

Abstract. The aim of the present study was to investigate and to make agro-ecological assessment of fresh (excreted up to 24 h) and stored (for 6 months) manure from different farm animals (dairy cows, pigs, laying hens and turkeys) by biogenic elements content (N, P, K) for a period of one year. Samples of fresh and stored manure were collected and analyzed monthly for total N, total P and total K content. It was found that: a) biogenic elements in fresh and stored manure decreased in the following gradation by average values for the studies period: turkeys – total N (13.9 – 9.16 g/kg DM), total P (9.94 – 8.67 g/kg DM) and total K (5.02 – 3.74 g/kg DM); laying hens – total N (13.6-9.95 g/kg DM), total P (9.27- 7.94 g/kg DM) and total K (5.56 – 4.60 g/kg DM); pigs – total N (8.30 -6.77 g/kg DM), total P (6.08-4.65 g/kg DM) and total K (3.56 – 1.61 g/kg DM); dairy cows – total N (5.62 -4.76 g/kg DM), total P (1.72 – 1.48 g/kg DM) and total K (2.99 – 1.72 g/kg DM); b) the change in nutrients content of different types of manures by seasons both in fresh and in stored manure are divergent; c) coefficients of variation values determined surveyed manures by content of nutrients from minor to significant variable (Cv = 9.30-37.5%); d) during the storage of the tested manures nutrient losses are the greatest for potassium (17.3-54.8%), followed by nitrogen (15.3-34.1%) and phosphorus (12.8-23.5%); e) the average losses of biogenic elements in manure by kind of animal species are in varying degrees: dairy cows (total N 15.3%, total P 14.0%, total K 42.5%); pigs (total N 18.4%, total P 23.5%, total K 54.8%); laying hens (total N 26.8%, total P 14.3%, total K 17.3%) and turkeys (total N 34.1%, total P 12.8%, total K 25.5%); f) the ratio between nutrients (N:P:K), both in fresh and in stored manure from different animal species vary in relatively wide limits both by seasons (12.6%N:18.1%P:56.3%K – 41.5%N:16.0%P:39.7%K) and by average of the studied period (15.3%N:14.0%P:42.5%K – 34.1%N:12.8%P:25.5%K).