Tackling the future challenges of Organic Animal Husbandry - vTI

! Agriculture and Forestry Research, Special Issue No 362 (Braunschweig, 2012) ISSN 0376-0723
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ported by Ayano (2005) for P. maximum unimproved that was fertilized with different animal manures
(Table 2). This might be due to different factors such as the soil fertility as well as the feed
offered the animals that produced the manure used for fertilizing the grasses. However, the trend in
the change in concentration of P with plant maturity is in line with the report of Minson (1990). The
P contents however fell within the recommended (1-4.8 g/kg) range for different classes of
ruminant animals as stated by McDowell (1992; 1997). The values recorded for Ca content of the
grasses as influenced by the manure types in this study is in consonance with the report of Chang et
al. (1994) in which the Ca content of zero-manured barley had higher concentration. This might be
as a result of salinity associated with manure application (Chang et al., 1991), also chelating properties
of manure could be responsible in which elements such as calcium are bond into a chelate with
the soil colloids and are release gradually and this is one of the importance of manure as they are
known for binding up mineral elements against being washed away during erosion. The requirement
of different ruminant animals in terms of Ca concentration ranged between 1.8 to 8.2 g/kg as
reported by McDowell (1992; 1997). The crude protein (CP) recorded for the grasses as affected by
the animal manure were within the range of 82– 112.8 g/kg reported by Bilal et al. (2001) when
farmyard manure was applied to P. purpureum (Table 2). The values were generally above the critical
limit below which forage intake by ruminants and rumen microbial activity could be negatively
affected (Van Soest, 1994). These values were also above the minimum range of 65–80 g/kg
prescribed for optimum performance of tropical ruminant animals (Minson, 1981).
Table 2. Effects of manure type and age at harvest on the phosphorus (P) calcium (Ca) and
crude protein (CP) composition of three grass species.
Factors P Ca CP
Manure type
Cattle 1.67 d 7.11 d 101.60 a
Swine 2.48 b 7.91 c 100.84 a
Poultry 3.33 a 9.51 b 88.95 c
Sheep and goats 1.90 c 9.76 ab 93.62 b
Control 1.89 c 10.41 a 84.94 c
SEM 0.2 0.4 2.9
Species
P. maximum (Local) 1.80 b 8.19 b 92.52 b
P. maximum (Ntchisi) 1.75 b 10.01 a 91.33 b
P. purpureum 3.22 a 8.62 b 98.22 a
SEM 0.1 0.4 2.4
Age at harvest (WAP)
4 2.24 b 9.19 b 110.60 a
8 2.53 a 10.15 a 101.54 b
12 2.59 a 8.65 b 90.52 c
16 1.66 c 7.78 c 73.32 d
SEM 0.2 0.4 1.9
P-value
Manure