Naturally growing grass strips were used indigenously as hedgerows by farmers in some Philippine upland areas. The Natural Vegetative Filter Strip (NVS) technology was developed to optimize its merits and develop appropriate recommendations for its application.
The strips filter pesticides, nitrates and soluble phosphorus, thus preventing runoff. They control soil erosion by more than 90%. They improve water infiltration during heavy rains.
Subsequent land preparation and crop management become easier. Farmers are provided with food foundation, and farms evolve into complex agroforestry systems, thereby increasing productivity ( Fig. 3(29)).
The NVS reduces the available cropping area by about 10 to 15%. However, the cropping area utilized for strips basically depends on the steepness of the slope. The steeper the slope, the greater the area used for strips. Farmers are advised to increase the number of strips if the slopes are really steep.
Basically, the strips do not cause weed problems as long as the farmers regularly maintain the NVS area and about 50 cms of its surrounding through continuous cultivation. If farmer maintenance is good, no weed problems will occur.
Natural Vegetative strips are easy to establish. They are incorporated during land preparation, and thus require minimal labor. They do not entail additional cost as there is no need for additional planting materials, since the grasses naturally grow on the farm.
Index of Images
Figure 1 Grassy Strips Running across Slopeland Field, Philippines
Figure 2 Natural Vegetative Strip for Agroforestry Cropping System (I)
Figure 3 Natural Vegetative Strip for Agroforestry Cropping System (II)
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