Effects of Poultry Litter Amended Steer Diets and Subsequent Manure Collecting Systems on Nutrient Recovery in Composted Manures

Abstract

Concentrate feeds have become an important feature of dairy cattle diets on small-scale farms in the Central Kenya Highlands. Excreta derived from such diets can be of high quality if nutrient losses are minimized. Steers were fed a basal diet of Napier grass supplemented with either commercial dairy meal at 0.5% of liveweight (low concentrate -LC) or dairy meal (0.5% liveweight) plus poultry litter (0.5% liveweight) (high concentrate -HC). The amount of faeces and urine collected, and the dry matter, N and K contents of the resulting manure composted with wheat straw were significantly higher with the HC than with the LC diet, and this was the case also for P and Ca content when urine was added. Significant linear relationships were observed between the daily N intake and the daily N collected in faeces and urine. Dry matter, N, K and Ca were also higher when urine was added to the faeces and straw during accumulation than when urine was excluded, and this was the case also for P with high concentrate diets. Appropriate manure management could significantly improve nutrient conservation on smallholder farms in the Central Kenya Highlands and contribute to the sustainability of intensive cropping.

Manure as a key resource within smallholder farming systems: Analysing farm-scale nutrient cycling efficiencies with the NUANCES framework

“…We derived the relative loss factor for mass and N during the manure collection period from experimental work of Lekasi et al (2002Lekasi et al ( , 2006) ( Fig. 2A and B).…”

“…The next step or "fuzzy inference" is to determine the set of if-then rules that define the system behaviour and the values of Lekasi et al, 2002Lekasi et al, , 2006. (A) Nitrogen remaining for further recycling, fitted functions: y (F) = e − 0.0039x , r 2 = 0.95 (P b 0.05), y (F + U) = e − 0.0011x , r 2 = 0.99 (P b 0.01), y (F + U + FR) = e − 0.0028x , r 2 = 0.99 (P b 0.05).…”

“…3D). The magnitude of the management factor (related to losses) used to translate back the linguistic variables were derived from Lekasi et al (2002Lekasi et al ( , 2006) (cf. Fig.…”