Factors Contributing to Citrus Mandarin Yield Decline in Dewathang Geog under Samdrup Jongkhar Dzongkhag

Abstract

A study was conducted to determine the factors responsible for yield decline observed in Citrus reticulata Blanco (locally known as citrus mandarin) in Dewathang Geog under Samdrup Jongkhar Dzongkhag. Seventy two farmers were randomly selected and interviewed using a structured questionnaire survey. Twenty eight composite soil samples were collected from 14 different citrus mandarin orchards to evaluate soil nutrients. The Chinese fruit fly and the green stink bug were the major causes of fruit drop, causing significant yield loss in 97% of the orchards. Citrus greening disease has completely destroyed three orchards and was observed in 35% of the remaining orchards, posing a serious threat. About 82% of the citrus seedlings were propagated from backyard nurseries, which may have led to the supply of poor planting materials. Majority (86%) of the growers only applied farm yard manure, which may have contributed to the low soil nutrient contents recorded in the orchards. These growers do not practice proper management practices such as pruning, basin making, and spacing. Considering the poor management practices and low soil nutrient status, there is a need to train the citrus growers in soil fertility and good orchard management.