Drought and early spring forage production in the Sierra Foothills

UC SFREC staff has been closely monitoring the seasonal pattern of forage production at the Research and Extension Center for over 30 years. These observations provide the longest running data set in the region to compare how the precipitation we receive each year influences the timing and amount of forage production compared to what we might expect on average. While this year is not as bad as last year in terms of forage production, the very dry January and February has not put us on a good foot as we head into early spring. Between January and February we should get about 10 inches of rain at SFREC but this year during this time period we only received about 25% of that amount. As a result, as of March 1^st we only have about 475 lbs of forage per acre on the ground while on average we would expect about 700 lbs of forage per acre. 

We went through January in a precarious state with only about 270 lbs of forage per acre on the ground by February 1^st when normally we should have about 500 bs of forage per acre by February 1^st, so the brief wet and warm period we had in early February (precipitation totals) did help us reduce the forage deficit. March is our second largest forage production month where on average we grow more than 800 lbs per acre ac so we need to see close to 1000 lbs per acre of growth in March to get us back on track for the season.

While March 1^st is an indicator of how well things were (or not) for the winter months, April 1^st has always been a better gauge as to where we might end up at peak standing crop. The table below shows several years that had similar forage values on March 1^st but ended up with large differences in forage by the end of spring. For example in 1979-1980 we started March at 500 lbs per acre and by the end of spring ended up with total forage production that was 56% of average while in 2001-2002 we started March at 447 lbs per acre and by the end of spring had forage production that was 93% of average. Last year, with the severe drought, we started March with 400 lbs of forage on the grounded and by the end of spring forage production was about 77% of average.

It is difficult to predict how this season will turn out as of today, but March is not looking too encouraging in the way of predicted precipitation for the month.  While this weekend's 0.21 inches of precipitation was a welcome site we are going to need more than a few thunderstorms to get us back on track. Our next round of data will come out shortly after April 1^st and will give us a more definitive idea of where the rest of the growing season may be headed.  For more information on long-term weather and forage production trends in the Sierra Foothills click here.  If you are interested in getting more information managing through low rainfall/forage years SFREC has a number of videos and publications that explore this topic.

To get more information about how producers can benefit from forage production data, click here.