H109-0005
Water use in non-irrigated cover crops for the benefit of nesting waterfowl in California Sacramento Valley
Friday, 11 December 2020
Poster
Kosana Suvocarev1, Henry Owen Perry2, Jenae Clay1, Mary Rose Mangan3, Shicheng Yan4, Emma C. Ware2, Mark E Lundy2, Mallika Arudi Nocco5, Luke Mathews6, Kyaw Tha Paw U1 and Bruce Linquist1, (1)University of California Davis, Davis, CA, United States, (2)University of California Davis, Davis, United States, (3)University of California Davis, Land, Air and Water Resources, Davis, CA, United States, (4)Northwest A&F University, Yangling, China, (5)University of Wisconsin Madison, Madison, WI, United States, (6)California Rice Comission, Sacramento, United States
Abstract:
California rice fields generate some of the highest rice yields in the world. But these systems also provide valuable habitat for a wide range of wildlife, including migratory and resident waterfowl. The development of this habitat shows the integration of highly intensive agriculture with valuable ecosystem services. However, breeding waterfowl populations in the Sacramento Valley of California have been in a continual state of decline since the late 1990’s. Loss of breeding habitat is considered to be one of the major contributing factors. While large scale conversion of lands back into permanent upland habitat is unlikely in the Sacramento Valley in the near future, there is an opportunity to create seasonal, upland nesting habitat on agricultural lands. The opportunity comes with fallowing that occurs with organic rotation in rice cropping or in direct relation to water sales that benefit both grower and California state water allocation. The creation of this seasonal habitat can be done by establishing cover crops in fallow rice fields and maintaining them through the waterfowl breeding season which provides a win-win solution for utilizing fallowed lands to both enhance soil health benefits and nesting habitat on agricultural lands.
Our study is motivated by the knowledge gap concerning water use related to cover crop evapotranspiration (ET). We conducted a measurement campaign over four fields, one fallow and three under different non-irrigated cover crops, to determine the amount of water being used particularly during the waterfowl nesting season in late spring and early summer by using eddy covariance measurements.
Our preliminary data showed that winter wheat exhibited the greatest ET water use. Vetch and vetch-mix cover crop fields used slightly less water. Fallow field had similar ET water losses to the water gains through precipitation. For comparison, the measured ET value of vetch and vetch-mix, a frequent cover crop with potential soil health benefits, was approximately one-third of water that would be used for irrigation if rice is grown for the full season. Since the cover crops are grown during the part of the year when the precipitation events are expected in California, some portion of their water use is supplied naturally through rainfall.
