CHANGES IN FRUIT YIELD, QUALITY AND NUTRIENT CONCENTRATIONS IN RESPONSE TO SOIL HUMIC ACID APPLICATIONS IN PROCESSING TOMATO

摘要

Humic acids (HA) provide formation of the organomineral in soil, thus they improve nutrient concentration of tomato leaves and agricultural production. The objective of this study was to find effects of soil HA applications on yield, fruit quality andnutrient concentration of processing tomato. Humic acid was sprayed on soil at the rate of 0, 40, 80, 120, 160 and 200 L ha~(-1) soil along with uniform dose of nitrogen-phosphorus-potassium (NPK) (180-60-210 kg ha~(-1)) was applied through drip irrigation. The experiment was conducted according to randomized complete block design with 4 replicates in 2011-2012 years. The humic acid applications caused a significant increase of yield. Titretable acidity, fruit weight and fruit diameter showed increaseby ascending humic acid levels. Results showed that N, P, K, Ca, Zn and Mn concentration of leaves was increased by humic acid, especially 80 L ha-1 humic acid level provided the most important progress in the first year. In the second year, N, P, K, Feand Mn concentration of leaves was positive changed by humic acid and high levels of humic acid caused decline. Therefore, mid-levels (80 and 120 L ha~(-1)) were found more effective.