Agriculture and Environment: Rice

Better Management Practices: Improve Water Management

New systems of rice cultivation allow producers to conserve much of the water that was used to cultivate rice 30 years ago.

In Australia, for example, more accurate laser siting and levelling of irrigated fields have reduced water use by some 25%. Improved control of water movement on and off the land reduces the opportunity for rice pond water to enter the water table from rice fields.

Other ways to reduce water use include growing shorter varieties with shorter seasons (meaning they ripen earlier). In Australia, such measures have reduced water use by 30% per hectare over the past 10 years and increased rice yields 60% per water used in the same period.

In California some farmers have begun to employ new recirculating irrigation systems plus automated shutoff valves that conserve up to two-thirds of the water requirements of 30 years ago. Rice fields that are tilled in the fall and left open to drain freely after each winter rain lose 30 times more soil than rice fields where the stubble is left standing and water is allowed to collect (Ducks Unlimited 2002).

Holding soil in the ponds makes downstream freshwater systems cleaner and consequently better wildlife and fisheries habitat. In addition, minimal fall tillage and ponding of winter rainfall promote the decomposition of rice straw and build organic matter in the soil. More thoroughly decomposed rice straw means less effort and expenditures at planting time.

Maintaining standing water in the water also appears to suppress germination and growth of winter weeds and thus reduces the work needed for spring field preparation.