Open Academy for Philippine Agriculture - Waste no more-- for a fertile and productive soil

Waste no more-- for a fertile and productive soil

Written by Written by: The Web Team
Tuesday, 26 August 2008
Hull, straw, and stubbles. These are common remnants on a newly harvested rice field. Most farmers consider them waste, but these bits and pieces can, in the long run, make the soil fertile and productive. A Philippine Rice Research Institute (PhilRice) study led by soil expert Evelyn Javier proved that rice farm wastes, when processed into organic fertilizer, can increase the indigenous nutrient content of the soil after three years of continuous application. “Organic fertilizer alone is not sufficient to feed the rice crop, but it enhances soil fertility and productivity through years of usage,” Javier said. When organic is important It has always been a persistent question whether a farmer can go purely organic. Experts say it is possible, but it will take lots of organic fertilizer to provide the nutrients a rice plant needs. “That’s why we recommend the use of both organic and inorganic fertilizers in tandem with correct farming practices if farmers want to achieve high yields,” Javier said. She also said a farmer tilling less than a hectare rice farm may, however, use pure organic fertilizer. “Small production areas need lesser amount of fertilizer. With the limited supply of organic fertilizer in the market, we only recommend pure organic farming for small areas,” Javier explained. On a larger scale, organic fertilizer enhances soil health or fertility. Long-term fertility tests have shown that the amounts of available nitrogen (N), phosphorus (P), and potassium (K) in the soil increased after three years of organic fertilizer use. “These nutrients (NPK) accumulate in the top soil where the roots grow. With combined rice straw and chicken manure application, P and K can even penetrate the subsoil layer, becoming potential nutrient reserves for the next cropping seasons,” Javier further explained. As the soil gets healthier every cropping season, inorganic fertilizer requirement also becomes lesser each year. Javier said that as organic fertilizer makes the soil fertile, it also boosts production. “With continuous use of organic fertilizer, the soil gets rejuvenated. More nutrients accumulate in the top and subsoil layers, hence making the soil more capable of producing healthy crops.” “We say that the soil is productive when it boosts the crop’s ability to produce grains through healthy roots,” Javier said. She also stresses that the use of organic fertilizer also increases the population and activity of inherent soil microorganisms. Studies have shown that this mechanism hastens the release of nutrients from the soil by the soil microorganisms for the nourishment of the rice plant. “There are lots of microorganisms in the soil. We simply need to feed them so that they can do their work. Organic fertilizer is a good substrate for their activities and fuels them to work towards improved soil fertility,” Javier said. Ways to go organic According to Javier, almost all seemingly useless things in the field can be actually used in organic farming. One simply needs to convert them to organic fertilizer. One way is composting of discarded plants materials, animal manure, and other biodegradable wastes. Conversion into organic fertilizer can be done with microbial-based inoculants (MBI). MBI is made from local materials such as sawdust, coco dust, carbonized rice hull, molasses, and then inoculated with effective microorganism (EM). Javier also advises in situ rice straw composting. This is the direct incorporation of rice straw, stubbles, and panicles into the rice field after harvesting. “To hasten the decomposition process, MBI is broadcasted and incorporated with the straw into the soil during the land preparation. Another option is to spray one liter of liquid EM to every 10 kg of rice straw,” Javier said. Aside from EM, Javier’s team found a cheaper but equally effective alternative to EM – chicken manure. “Although some say that chicken manure is not anymore organic due to the chemical components of feeds given to chickens, we still consider the manure as organic waste. We are promoting its use as fertilizer due to its inherent high nutrient content as well as decomposer of rice straw due to the presence of enzyme and substrates ideal to enhance microbial population and activity,” Javier explained. Javier said a pack of EM used to produce 1kg solution costs P30 while a 50-kg bag of chicken manure only costs P25. In addition, the latter is proven to have high phosphorus content, other micronutrients and enzymes. The Bureau of Soil and Water Management promotes other composting technologies such as the use of Trichoderma harzianum (fungal activator) and vermicomposting (use of worms). PhilRice, meanwhile, included vermicomposting as a component of its Palayamanan project. This project is an integrated rice and rice-based farming system which aims to provide additional income for farmers by engaging in vegetable, mushroom and worm production, among others. In the long run “I am not saying that inorganic should be substituted with organic fertilizer. However, based on our study, continuous application of organic together with inorganic fertilizer maintains and even increases the richness of the soil,” Javier said. This practice, along with other affordable nutrient management technologies like the Leaf Color Chart and Minus-One-Element Technique will lessen the burden Filipino farmers of skyrocketing cost of fertilizers. Another is the reduction of pollutants coming from farm wastes. Javier said by converting them to organic fertilizer, they indeed are wastes no more.