ORGANIC FERTILIZERS AND MICROBIALS FOR IMPROVED SOIL FERTILITY IN ORGANIC VEGETABLE PRODUCTION IN CAR

Carlito P. Laurean, Asuncion L. Nagpala

ABSTRACT

The research was conducted at the BSU Experiment Farm from August 2010 to December 2013. The general objective of the project is to enhance organic vegetable production and develop it as an entry point for livelihood enterprise in Benguet. Specifically, it aims to develop organic fertilizer products and systems utilizing locally available materials and microorganisms to support and enhance the organic vegetable production enterprise in Benguet.

The nutrient contents of liquid organic plant nutrient supplements such as fermented plant juice, fermented fruit juice based from the concoctions of farmers were analyzed and found to be very low to sustain crop growth and development. Thus, a new formulation using legume seeds was done where nutrient contents were much higher.

Likewise, solid organic fertilizers were also formulated using locally available raw materials. The result showed that using 50% chicken manure, 25% sawdust and 25% sunflower leaves and Trichoderma gave the highest nutrient contents.

The result of analysis also showed that both liquid and solid organic fertilizers contained all the essential nutrient elements required by most crops.

Bacterial and fungal isolates were tested for lettuce crops and the results were promising. Bacterial isolates are for further verification while Trichoderma was found effective as microbial fertilizer other than its use as bio-control agent.

The solid organic fertilizer, reformulated organic liquid plant nutrient supplements Trichoderma were tested on cabbage and carrot grown in farms under conversion to organic production. Lower yields were observed during the early part of conversion. However, after three years of conversion, the yield of cabbage and carrot have significantly increased which are comparable to the yield in conventional farms.

Nutrient management system for farm under conversion and in organic farm was likewise studied. The recommended rates of formulated organic fertilizer and re- formulated organic liquid plant nutrient supplements both for cabbage and carrot are 10/ha and 60ml/ li of water respectively. A mineralization study on the formulated organic fertilizers were done as basis on determining the best time of organic fertilizer application. It was determined that solid organic fertilizer should be applied three times, that is, before planting, 15 days after planting and 30 days after planting to coincide with hilling- up. This is to stimulate the effect of synthetic fertilizers where nutrients should be made available when plants need them to prevent nutritional deficiencies.

Likewise, the physical, chemical and biological properties of conventional farm under conversion to organic farm showed significant improvement during the 3- year conversion. More porous soils were observed on the 3rd year of conversion. On the other hand, more beneficial microorganisms were counted in the organic farms as compared in conventional farms. Likewise, pesticide residues and heavy metals that were detected at the start of the study were no longer detected in the 3rd year of conversion.

Key words: organic liquid plant nutrient supplement, solid organic fertilizer, microbial fertilizer, nutrient management, conventional farm, organic farm