2008 Joint Annual Meeting (5-9 Oct. 2008): Effects of Storage Methods on Manure Systems and Manure Decomposition in Soil in Small-Scale Kenyan Systems.

Cattle manure is a commonly used soil amendment that, with proper management, can provide plant-available N but manure management techniques vary among smallholder Kenyan farms.  This study aimed to examine the effects of manure storage method on the neutral detergent fiber-bound N (NDIN) content of manure.  Management strategies were varied in terms of how the manure was contained and shaded, and how frequently fresh material was added to the pile. In a randomized complete block design experiment, manure samples from one better-managed dairy farm (Farm A) and from one with inferior management (Farm B) were stored for 30 d to determine if the management methods and the manure source affected the N composition of the manure. Every 6 d, 3 replicates of each of 8 treatments were non-destructively sampled.  After 30 d, the manure was buried in soil in large- and small-mesh litterbags to determine the disappearance of organic-N over four mos.  For each of the 24 storage replicates, there were 7 litterbags of each size to be removed from the soil at 7 intervals over 112 d.  Only the manure source (P<0.01) and the time in storage (P<0.01) affected the N composition of the stored manure.  Manure source, i.e. the herd that produced the manure, was also the only factor that affected the NDIN disappearance in soil (P<0.01).  Preliminary data: 

	Farm			Mesh
				Small	Large
%NDINsd, after 30d storage	A	4.10.9	%NDIN lostsd after 112d in soil	4.90.8	6.90.1
	B	4.60.8		1.31.2	5.10.6

The manure from the better-managed farm degraded faster, suggesting that more nutrients would be available to plants within one growing season if this manure was used as a soil amendment.  These results suggest that a good area of focus in manure management may be on the cattle diet, which affects manure quality and its decomposition in soil.