|Fact sheets about Rice Weeds|
|The Dirty Dozen|
Weeds are becoming increasingly important primarily due to limitations in both water and labor availability. Crop intensification and direct seeding are increasing and these changes mean that weeds can be more costly and more difficult to control. For example, the development of new varieties and irrigation opened the door for increased intensification and profits for farmers. The combination of the use of shorter stature varieties, plus the increase in intensification has resulted in greater weed pressure due to less competitive (shorter stature) varieties. Multiple rice crops mean more weeds.
Another shift is the move to direct seeding as labor prices become higher. Direct seeding (especially dry direct seeding) results in greater weed pressure. The traditional system of transplanting gave the crop a competitive advantage over the weeds. In addition, the crops were usually transplanted into standing water – which was an additional factor reducing weed pressures.
Finally, the increasing and sometimes indiscriminate use of herbicides has resulted in weeds that are now resistant to herbicides. Such a shift reduces the number of options open to farmers.
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