Maintaining Yield under Organic Fertilizer Management in Khao Dawk Mali 105 and Kum Bangpra Rice Varieties

Abstract

       This study aimed to assess the effect of different fertilizer management on yield and yield component in two rice varieties, Khao Dawk Mali 105 and Kum Bangpra. Split-plot design with three replications was conducted for this study. Fertilizer management was assigned to the main plots, while rice varieties were allocated to the subplots. Ten different fertilizer management practices were employed, each designated as follows: T1) no fertilizer, T2) chemical fertilizers, T3) 500 kg./rai cow manure, T4) 1,000 kg./rai cow manure, T5) 150 kg./rai poultry manure, T6) 300 kg./rai poultry manure, T7) 500 kg./rai cow manure + 150 kg./rai poultry manure, T8) 500 kg./rai green manure + cow manure, T9) 150 kg./rai green manure + poultry manure, and T10) green manure + 250 kg./rai cow manure + 75 kg./rai poultry manure. The results indicated varying responses to fertilizer management between the local rice varieties. KDML105 tended to exhibit a stronger response to organic fertilizer compared to KBP. Following treatment with 150 and 300 kg./rai of caw manure, yields of KDML105 increased by 14-16% compared to chemical fertilizer application while yields remained lower in KBP variety. However, after applying green manure combined with cow manure of 250 kg./rai and poultry manure of 75 kg./rai, the result showed a significant increase in KBP yield, up to 24% compared to chemical fertilizer application. Therefore, organic fertilizers with lower nutrient application rates often yield similar results to those achieved under adequate chemical fertilizer application.