California Agriculture

Water management practices in Califonia rice production can affect salinity in the field. This is particularly important because rice is one of the most sensitive crops to salinity. We extensively monitored salinity patterns in dozens of rice fields in Colusa and Glenn counties, in order to determine how salinity varies from basin to basin and to compare salinity patterns under different irrigation systems. We found that the fields most vulnerable to salinity damage were those with higher soil salinity and using irrigation water sources initially high in salinity, particularly nondistrict sources that are combinations of well and drain water. Long water holding periods, while effective in reducing pesticide concentrations in rice fields, can contribute to salinity increases in bottom basins. Salinity can increase with either conventional or static irrigation management systems, but the salinity pattern in the field will be different.