Agroecosystems manipulation to improve sericulture-based farming systems in the Ilocos provinces, Philippines

Three inter-related studies were conducted and aimed at improving the existing sericulture-based farming systems in the Ilocos. The first study involved an appraisal to thoroughly understand the farmers' existing sericulture practices, and identify their most pressing problems. Six agroecosystems were then designed and evaluated in Tinaan, Sta. Maria, Ilocos Sur from March 2002 to Dec 2004 to select the best combinations of practices using Batac mulberry variety and silkworm DMMMSU-218 hybrid from DMMMSU-SRDI. Data were analyzed using SAS and SPSS software. Weed infestations, low soil fertility, low quality of mulberry leaf and lack of irrigation facilities were the problems in mulberry production. Low hatching percentage of silkworm eggs, high disease incidence of silkworms, low yield of quality cocoons, limited facilities for rearing, inadequate quantity of mulberry leaves and low quality mulberry leaves for rearing, were the problems in silkworm rearing. Lack of operational funds, rising costs of materials and labor, long time to recover investment, limited market of cocoons, low price and low grades of cocoons, were the identified financial problems. No significant increases of pH and potassium contents of soils were observed in different agroecosystem manipulations from the first to the second year of the study. Organic matter declined in pit planting + 200-50-50 kg NPK/ha + 10 tons manure (Conventional 2) and row planting with 200-50-50 kg NPK/ha + 10 tons manure (Conventional 1) and row planting + 100-50-50 kg NPK/ha (Existing practice) but continued to increase in pit planting + 100-50-50 kg NPK/ha + 10 tons manure + green manure + mulch (LEISA 1), pit planting + 50-50-50 kg NPK + 10 tons manure + green manure + green leaf manure + mulch (LEISA 2), pit planting + 10 tons manure + green manure + green leaf manure + mulch (Organic Farming 1) and pit planting + green manure + green leaf manure + mulch (Organic Farming 2). An increase in the amount of potassium in the soil was observed. LEISA 1, LEISA 2, and Organic Farming 1 were the three systems that improved the soil fertility (organic matter content). Mulberry plants had higher mulberry leaf yields (taller mulberry plants, longer shoots, heavier single leaf weights), higher protein contents and acceptable range of moisture contents (high moisture contents for young-age silkworms and low moisture contents for late-age silkworms), two major leaf qualities favorable for cocoon production. Cocoon yields per hectare were also higher in these three agroecosystems. There was higher effective rearing rates of silkworms, weight of ten matured larvae, single cocoon weights and cocoon yield per box and quality of cocoons as to cocoon shell percentage, percent good cocoons and reelability improved. Ultimately, with cocoons and other products, LEISA 1 provided the highest combined net incomes followed by LEISA 2 and Organic Farming 1 and returns on investments, returns above variable costs, returns to material and labor costs were also higher in these three systems compared with the Existing Practice.