Improving Productivity, Profitability and Sustainability of Degraded Grasslands Through Tree-Based Land Use Systems in the Philippines - Smallholder Tree Growing for Rural Development and Environmental Services - page 280

Table 14.1 Description of land use systems considered in the study
Land use system Description

IMPLUS Imperata land use for animal

pasture or grazing system

FPLUS Farmer's current practice of annual

maize cropping system (100 percent of the

area devoted to maize)

TIMPLUS Timber species with Imperata

for animal pasture or silvopastoral

system (85 percent is allocated to

Imperata and 15 percent is planted to trees)

TCLUS Timber species planted in hedgerows

with annual maize cropping

system at the alley areas (85 percent is

devoted to maize and 15 percent to timber)

TCSFLUS Timber-maize system where bigger

area is planted to timber species in

hedgerows with annual maize cropping

at the alley areas (40 percent devoted

to timber and 60 percent devoted to maize)

TPLUS Timber plantation land use system

(100 percent of the area devoted to timber)

were allowed to regrow in the subsequent year. FPLUS refers to a continuous open-
field maize cropping system where soil is cultivated prior to planting maize seeds.
In the model, inorganic fertilizers were applied during the growing season at 60 kg
ha −1 /cropping for nitrogen and 24 kg ha −1 /cropping for phosphorus. The FPLUS was
modeled with 100 percent of the area devoted to maize production.
In the case of TIMPLUS, 85 percent is allocated to Imperata (treated as crops)
and timber trees occupy only 15 percent of the total area. Modeling scenario for
TCLUS was based on current land use practice in the area where 85 percent is allo-
cated to maize cropping at the alley areas and the remaining 15 percent is planted
to timber species in hedgerows. TCSFLUS, a variant of TCLUS system, is an adap-
tation of the social forestry agroforestry model where 40 percent is planted to tim-
ber trees in hedgerows while the 40 percent alley areas is devoted to annual
cropping of maize. Two tree-species were modeled in the timber-based systems: (i)
Gmelina arborea (non N-fixing tree) and Acacia mangium (N-fixing tree). Except
for TCSFLUS system, all tree-based systems allocated 60 percent of the tree com-
ponent to Gmelina arborea and 40 percent to Acacia mangium . In TCSFLUS sys-
tem, the tree component was planted equally (50 percent of 0.4 ha) to both timber
tree species. Timber seedlings were planted with 3 × 4 m spacing, yielding a density
of 834 trees per hectare. A block planting method was used for timber plantation
system (TPLUS). Pruning of branches and twigs of trees were done in all tree-
based systems during the first 2 years of the rotation interval to induce straight
growth of Gmelina and Acacia .
Farmers preferred to cut Gmelina trees at seven years (Magcale-Macandog et al.
1999), however, majority of tree growers in the survey reported the best age to harvest