Growing and feeding sugarbeets to dairy cows in the San Joaquin Valley of California.

Abstract

Sugarbeets were widely grown throughout California during the 20^th century, but the last sugar factory in the northern California closed in 2008.  In the absence of a sugar industry, interest in the use of sugarbeets as a silage feedstock for dairy cows has grown, especially in the San Joaquin Valley (SJV).  Increasing regulatory restrictions on the availability of water for irrigation and stricter controls on nutrient management support the use of alternative crops by dairy producers that are both water use efficient and capable of recovering both water and nutrients at depth in the soil profile.  Sugarbeets can be planted in fall in the SJV, and harvested in late spring/early summer.  When grown through the winter, water use is approximately half that of a summer crop (2 ac ft compared to 4 ac ft).  Beets have been documented recovering water and nutrients at 3 m in depth, deeper than alternative winter annual forages.  Most pests and pathogens common to summer crops are avoided during winter.  If winter beet production proves viable on dairies in the San Joaquin Valley, a large market for hybrid seed would develop, potentially dwarfing previous uses for sugar alone in the region.  Four trials on dairy farms growing and feeding sugarbeets for silage have been carried out during the 2018 to 2022 period.  Beets were planted using strip tillage methods following corn silage in fall (late October and early November) in heavily manured fields and harvested in early to late June.  Root yields varied from approximately 60 t/ac to 43 t/ac depending largely on stand establishment and uniformity.  Tops were not harvested due to concerns about nitrate content and technical limitations around harvesting and feeding.  No pest or disease issues were observed except for flea beetle predation on seedlings in year three at one site.  A formal feeding trial was carried out in year there and beet-almond hull silage replaced corn silage and some corn grain in rations fed to high producing cows with no change in yield or milk quality.  Cows consumed rations avidly and body conditions scores were equivalent throughout the trial.  In years one and two, beets were co-ensiled with almond hulls and both years, in years three and four, beets were co-ensiled or ensiled with additives.  Significant barrier to the wider-scale adoption of beets on diaries in the SJV remain.  These focus on difficulty of preserving dry matter energy in beets during storage.  In two years of measurements, shrinkage (loss) of preserved dry matter was continuous throughout the storage period and averaged 35 %, compared to 5% or less for corn silage. Other barriers to adoption are the need for beet harvesters, some adjustments in forge wagons, the need for ag bags compared to bunker silos for preservation, and slower harvests and handling.  These problems have not been solved adequately to date, especially those concerned with storage DM losses.