Philippine Journal of Crop Science 2001, 27(1): 43-51 Copyright 2003, Crop Science Society of the Philippines Released October 2003 EVALUATING THE MANY BENEFITS OF SUGARCANE TRASH FARMING SYSTEMS TC MENDOZA', R SAMSON' & T HELWIG2 Research funded by the National Renewable Energy Laboratory (NREL), USA, "Strategies for Enhancing Biomass Utilization in the Philippines" Subcontract AXE-0-30001-01 Department of Agronomy UP Los Banos, College, Laguna, Philippines. email: tcm@mudspring.uplb.edu.ph 2 Resource Efficient Agricultural Production (REAP) Canada, Box 125, Ste Anne de Bellevue, Quebec, Canada H9X3V9 Tel (514)398-7743, Fax(514)398-7972 REAP@Interlink.net, www.reap.ca The primary benefit of trash farming is the reduction of N fertilizer that is required to maintain high crop yields because of asymbiotic N fixation from the decomposing trash litter. Studies indicate that 50-200 kg N/ha can be fixed/year in a trash- mulched ratoon crop. Phosphorus fertilization can also be reduced, as the mulch protects the soil from drying, leading to more root proliferation in the soil surface where P levels are high. Sugarcane trash farming can lead to about 50% reduction in tillage expenses through extended ratooning under a 1:3 years plant-crop:ratoon-crop cycle compared to current practice (normally 1:1 or 1:2 years). Other benefits of a trash mulch: It reduces need for inter-row cultivation by 50%, improves soil fertility, prevents soil erosion, increases water retention, and minimizes lodging of de-trashed cane crops. Not burning the trash removes the human health hazards associated with the exposure to airborne particulate matter (fly soot and biogenic amorphous silica) when the canefield is burned. Trash farming significantly increases the economic return of cane production when compared with conventional farming methods. Although net revenue decreases by 4% in the plant crop (( 1184/ha), the net revenue increases by 28% (( 8924/ha) in the ratoon crop. This is primarily due to increased yields and 10% reduced cost of production on per ton cane (( 568/TC in conventional ratoon, 508/TC in trash-farmed ratoon). Trash farming decreases the overall energy input required per ton of cane produced. Conventional cane is estimated to consume 0.52GJ in the plant crop and 0.46GJ/TC in the ratoon crop. Trash-farmed ratoon cane reduces the energy demand to 0.24 GJ/t. The 48% improvement in energy use was the result of a 20% increase in cane ratoon yield under trash farming and a 110-kg/ha reduction in N fertilizer input per year. The 36% savings in energy per ton cane translates to about 3.24 M GJ energy savings for the sugar industry, equivalent to 618,000 barrels of oil or $18.54 M (( 964 M) at 30/barrel. Ways on how to promote and optimize sugarcane trash farming are presented. Keywords conventional farming, energy savings, N fertilizer, P fertilizer, plant crop, ratoon crop, sugarcane farming, trash farming, trash mulch INTRODUCTION Sugarcane is the major crop in the world that is most efficient at converting solar radiation into plant biomass. Unfortunately, this scientific fact is not being fully harnessed in the Philippines. The industry is in a long- term state of decline. From a high of 2.6-2.8 Mt of raw sugar in the mid-1970s, production has dropped to about 1.6-1.8 Mt by the 1990s. The country was the world's fourth largest exporter of sugar in the early 1980s. In 1995-96, the Philippines imported 816,668 mt of raw and refined sugar, whereas in 1977-78, the Philippines supplied 10% of the world's sugar requirements. Sugar exports contributed to about 20% of the country's export earnings at that time. The sugar industry is a major contributor in terms of employment as it provides about 500,000 jobs directly and an additional 5.0 M jobs indirectly (Zabaleta 1999). The decline in production can be attributed to many factors which include typhoons, floods, drought, pests, low application of inputs, reduced production land base, and most importantly, deteriorating soil fertility. Soil