A study was done to test different weed-killing chemicals in rice fields. They found that using pendimethalin and bispyribac together was the best at controlling weeds and increasing rice yield. Pendimethalin alone was good at killing grassy weeds. The most rice was grown when weeds were removed by hand twice, or when bispyribac was used after pendimethalin, butachlor, thiobencarb, or oxadiargyl. This shows that using specific herbicides in a certain order can help farmers grow more rice.