A. Rigueiro-rodriguez et al., Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain, AGROFOR SYS, 48(3), 2000, pp. 245-256
The use of organic waste materials such as milk sewage as an organic fertil
izer could have the dual advantages of organic-waste disposal and reduced d
ependence on inorganic fertilizers. The effects of fertilization with (1) c
onventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha(-1)
target rate and (3) no fertilization on pasture production and tree growth
were examined in an experiment consisting of two pasture mixtures under a
one-year-old Pinus radiata plantation with a density of 2500 trees ha(-1).
The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 k
g ha(-1)) + Trifolium repens L. group Ladino (4 kg ha(-1)) + Trifolium prat
ense L. var. Marino (1 kg ha(-1)); (2) Lolium perenne L. var. Tove (25 kg h
a(-1)) + Trifolium repens L. group Ladino (4 kg ha(-1)) + Trifolium pratens
e L. var. Marino (1 kg ha(-1)). The experiment began in the spring of 1995
using a randomized block design with three replicates in Castro Riberas de
Lea (Lugo, Galicia, north-western Spain). Plot size was 12 x 8 m(2), with a
1 m buffer strip between plots. Two-year data showed that fertilization wi
th either material had a positive effect on pasture production, with no sig
nificant difference between the two fertilization treatments. Tree growth i
n the milk sewage sludge plot was significantly higher than in the control
plots. Inorganic fertilization increased pasture production, but affected t
ree growth negatively. The results show that milk sewage sludge could be us
ed as a fertilizer in silvo-pastoral systems.