N Subba* , NP Adhikari**, K Ghimire** and ASR Bajracharya***
*Horticulture Research Division, NARC, Khumaltar
**Crop and Horticulture Directorate, NARC, Khumaltar
***Entomology, Agricultural Research Station, Pakhribas
Abstract
The growing demand of quality organic tea with increase in awareness on the deleterious effect of Chemicals and its residue in human health has revived the need of organic tea management. Field experiments were conducted in 2006/2007 to 2007/2008 in Ilam and Dhankuta districts to study the effect of different organic sources of nutrients and pest management on Orthodox tea cv. Gumti Selection. In addition to productivity, the effect of nutrients on green leaf production trend, plucking intervals in different months and changes in composition of soil in the experimental plots were also studied. Four different organic sources of nutrients; vermi compost, azatobacter incorporated commercial organic fertilizer, improved ditch compost with EM, traditionally made compost and different organic plant protection methods; enanthole, parasitic fungi Trichoderma viride, mineral oil for management of blister blight disease and locally made botanical pesticide, mineral oil and ultineem for management of thrips were tested separately in a Randomized Complete Block Design (RCBD) with seven replications. The effect of different organic sources of nutrients was found significant on green tea leaf production. In both districts, highest production of green tea leaves was recorded in plots with azatobacter incorporated fertilizer and least in farmers traditional compost in both years. The result showed green leaf production of 3125 and 3031 kg/hac in 12-15 year old plantation and 1822 and 1798 kg/hac in 8-10 year old plantation with yearly application of 495 gm/bush of azatobacter incorporated fertilizer. Different organic treatments did not differ significantly in the severity of blister blight disease. However, lowest infestation was observed in plots with Trichoderma application. Leaf damage percentage was found significantly lower in treatments other than control in both districts. The effect of organic thrips management was significantly different in green tea leaf yield. Non significant changes in soil chemical properties due to organic nutrients were found among the treatments. However, small increment in nitrogen and potassium content over the time was observed.
Keywords: Gumti Selection, mineral oil, enanthole, azatobacter incorporated fertilizer