MANILA, Philippines -- A five-year experiment has proven that it is advantageous to use paraquat (Gramoxone) in suppressing weeds in sloping areas and planting the same without any plowing. After suppressing the weeds, the seeds or seedlings are planted by dibbling.

The five-year experiment was conducted by a team of agricultural researchers in sloping areas in Quezon where corn is usually planted one crop after another, and in Benguet where vegetables like cabbage and potatoes are grown in mountainous terrain. The research team was headed by Dr. Gil Magsino of the National Crop Protection Center in Los Baños, Laguna.

The study, titled “Gramoxone Sagip-Lupa (GSL) Soil Conservation and Weed Management Technology” was initiated by Syngenta Philippines. It was aimed to find out how soil erosion can be minimized in sloping areas and at the same reduce the cost of crop production.

The five-year study ended earlier this year, and the conclusion is that over-all, the GSL technology proved to be an effective alternative remedy in minimizing soil erosion while providing high yield and excellent weed control in sloping areas.

The researchers concluded that the farmers benefited economically and agronomically with the technology which is very important in attaining sustainability in agriculture.

In Brgy. Bucal, Tiaong, Quezon where corn is planted in sloping terrain, the researchers used Gramoxone to suppress the weeds and planted the seeds without plowing the field. The field was ready for planting by dibbling the seeds only two days after application of the herbicide..

This is in contrast to the usual farmers’ practice of plowing and harrowing the field two times, leveling and furrowing the same, and planting two to three seeds per hill. Then, 15 days after planting the plants are off-barred. Selective manual weeding is done 50 to 60 days after planting.

The disadvantage of the farmers’ practice is that serious erosion occurs and the cost of production is also higher. In Tiaong, for instance, the accumulated amount of eroded soil for five years was 119.42 tons per hectare under the farmers’ practice. On the other hand, the accumulated eroded soil under the GSL technology was only 44.30 per hectare in five years. This is lower than the threshold level of 50 tons per hectare every five years recommended by FAO.

In the case of vegetables in Benguet where the slope was 30 percent, soil erosion was reduced by 55.05 percent with the use of GSL technology. The GSL only contributed 15.22 tons per year per hectare erosion as compared to the farmers’ practice which had 33.85 tons per hectare per year or a soil erosion difference of 18.63 tons per hectare per year in a cabbage-potato-cabbage cropping pattern.

Aside from minimizing soil erosion, the GSL technology enabled the farmers to save on cost of production. Based on tillage practices, input costs were greatly reduced in the farms using GSL technology.

For instance, the input costs in corn production in Quezon was only P3,350 per hectare under GSL while that of farmers’ practice was P5,400 per hectare.

In cabbage in Benguet, the input costs under GSL was only P8,950 per hectare while that of farmers’ practice was P21,750. In potato, the input cost in GSL was P7,875 compared to P20,650 under the farmers’ practice.

Aside from Dr. Gil Magsino, the other members of the research team included S.M. Medina, C.M.C. Manzanilla, M.M. Magallona, E.V. Cardona Jr., O.M. Lorenzana, N.E. Padilla, M.C. Casimiro and E.C. Martin.

Dr. Magsino explained that paraquat or Gramoxone immediately kills the weeds after application so that the field can be planted immediately. He adds that the herbicide only kills the above-ground parts of the plants. The roots in the soil are intact so that they hold the soil together.

The research team said that sustainable agriculture is essential for our survival, especially with rapidly increasing population. Expansion of agriculture in the country’s remaining areas of natural vegetation is undesirable as this leads to reduction of biodiversity. Maintaining or improving crop yields and protecting the existing farmed land is thus necessary.