2017 ASHS Annual Conference

Fertigation can be a successful method to apply plant available nutrient to crops, especially under organic farming. The need for affordable soluble fertilizers derived from local resources is crucial for agriculture sustainability and growers profitability. A recipe to produce liquid organic fertilizer, with high nitrate (NO₃-N) content, was developed locally in Hawaii through a Western Sustainable Agriculture Research & Education (SARE) funded project (SW14-026). The recipe was used to improve the seedling quality of five crops (sweet corn, chili peppers, tomato, kai choy, and papaya). Seeds were planted in 50 cell trays filled with Sunshine potting mix. Each crop was planted in 3 trays (replicates) in a complete randomized design (CRD). The liquid organic fertilizer was compared with two controls (liquid synthetic fertilizer and water only). Fertigation treatments were applied weekly, beginning one week after seed germination. At transplant time, 10 seedlings from each tray were randomly selected. Seedling height, fresh and dry weight (seedling were dried for 72 hours at 70^oC) were recorded. The liquid organic fertilizer showed highly significant (P < 0.01) results for all measured parameters, compared to synthetic and water only. Also, liquid synthetic fertilizer showed significant (P < 0.05) results compared to water only treatment. Percent increase in fresh and dry weight, for the five crops, between liquid organic/liquid synthetic, liquid organic/water only, and liquid synthetic/water only treatments varied between 12-49%, 40-79%, and 27-58%, respectively. Improving the quality of seedlings is expected to lead to uniform field growth, earlier harvests, and higher yields.