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Rice yield losses by competition with weeds in rainfed paddy fields in north‐east Thailand
Author(s) -
TOMITA SHINSUKE,
MIYAGAWA SHUICHI,
KONO YASUYUKI,
NOICHANA CHAIRAT,
INAMURA TATSUYA,
NAGATA YOSHIKATSU,
SRIBUTTA AKKADET,
NAWATA EIJI
Publication year - 2003
Publication title -
weed biology and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.351
H-Index - 36
eISSN - 1445-6664
pISSN - 1444-6162
DOI - 10.1046/j.1445-6664.2003.00101.x
Subject(s) - transplanting , competition (biology) , agronomy , weed , paddy field , yield (engineering) , economic shortage , agriculture , seeding , biology , resource (disambiguation) , yield gap , environmental science , crop yield , ecology , sowing , computer network , linguistics , philosophy , materials science , government (linguistics) , computer science , metallurgy
Economic growth in recent years has induced a labor shortage for agriculture in north‐east Thailand. Labor‐saving techniques, such as the replacement of transplanting with direct seeding, have become widespread. Direct seeding methods have advantages over transplanting regarding labor savings and reductions in production risks, but may cause weed problems. Therefore, rice yield reduction by competition with weeds becomes a potential problem in this region. In the present research, the extent of weed competition in rice production from the viewpoint of resource level and disturbance intensity was studied. A large number of paddy fields from a wide range of climatic, topographical, soil and hydrological conditions were analyzed. The survey was conducted every 3 weeks, and data on paddy cultivation, weeds and water conditions were recorded. Average yield of direct seeded rice was significantly lower than that of transplanted rice. The yield decreased with resource decreases in both direct seeded (DSF) and transplanted paddy fields (TF). Although the yield was not different under resource‐rich conditions, the yield of direct seeded rice was lower than that of transplanted rice under resource‐medium and ‐poor conditions. Competition intensity was not different among resource levels or between DSF and TF. Competition intensity in all fields was between 0.02 and 0.09 on average, indicating 2–9% yield losses caused by competition with weeds regardless of resource level and disturbance intensity. This suggests that low yield of direct seeded rice under resource‐medium and ‐poor conditions was not mainly caused by competition with weeds, whereas yield losses by weeds were observed in all field types. However, from an economical viewpoint, weeding should be applied only to limited parts of this region with stable and relatively high rice yields.