- Author: Megan G Osbourn
Project Summary:
As precipitation more frequently departs from the historical range of variability, maintaining stability in forage production will be a critical management priority in Californian rangelands. A key mechanism that can lead to stability in forage production is compensatory dynamics, where plant functional groups respond differently to climate fluctuations (e.g.,taprooted forbs like Erodium tolerate drought, annual grasses are highly productive in non-drought conditions).
Researchers hypothesize that trade-off among functional groups should buffer the response of overall forage production to climate variability and better retain soil nutrients in dry-wet up cycles. The specific objectives are to: 1) quantify relationships among the fate and retention of nitrogen, soil moisture dynamics, and species compensatory dynamics in drought and non-drought conditions; and 2) incorporate these relationships into process-based models of nitrogen retention and forage production in rangelands.
This project will ultimately lead to more informed decision-making for ranchers interested in optimizing forage production and nutrient retention in the face of a highly variable future climate. It addresses an often overlooked but critical component to the stability of ecosystem processes: functional diversity of forage groups.
Researcher, Lauren Hallet explains the preliminary progress of this project in detail in the below video. Stay tuned for more information as samples are taken this spring.
Principle Investigator: Dr. Katherine Suding, ESPM, UC Berkeley
- Author: Dustin Flavell
We went through January in a precarious state with only about 270 lbs of forage per acre on the ground by February 1st when normally we should have about 500 bs of forage per acre by February 1st, 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 1st is an indicator of how well things were (or not) for the winter months, April 1st 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 1st 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 1st 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.
- Author: Maddison Easley
- Contributor: Dustin Flavell
Rangeland specialist Jim Clawson first initiated the forage production data collection at UC SFREC in 1979. Past Director Mike Connor expanded the process with monthly (rather than seasonal) sampling of the usable forage in a particular area. Three plots were originally set aside to sample, but following multiple trials one specific plot was chosen. The same 1-acre grazed plot has been used for the past 35 years, as it is located at a median elevation with moderate canopy cover and a fairly representative soil of the entire ranch.
This year's forage production data was rather interesting. Late fall rains followed by freezing temperatures during germination, coupled with the severe winter drought, created dismal forage growth at the beginning of the yearly cycle (typically starting in December). However, the heavy rainfall experienced at the end of January and in the following months proved sufficient enough to produce nearly 80% of average forage production. As the person who has taken responsibility for keeping track of the forage production measurements and compilation, UC SFREC Superintendent Dustin Flavell has noticed an interesting trend; the total amount of precipitation is not always strictly correlated with the total pounds of forage produced per acre. “The right amount [of rainfall] at the right time and frequency will result in the most growth,” said Flavell.
Producers may find it useful to monitor forage production and peak standing crop on their own ranches. While there are varying definitions of peak standing crop, at UC SFREC it is measured when a majority of the grasses begin to cure but do not reach full maturity (seeds ready for dispersal). Peak standing crop typically occurs early to mid May. Several publications are available from the research conducted on forage production and residual dry matter that go into more depth about the importance of monitoring grass growth. One particular publication offers a simple 6-step method for determining forage in pounds per acre.
With a new growing season just around the corner, be on the lookout for additional posts regarding forage production at UC SFREC.
Here are some additional links for more information about this topic:
http://californiarangeland.ucdavis.edu/Monitoring_Annual_Rangeland_Forage_Production/
http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=14157
http://sfrec.ucanr.edu/Data/forage/
- Author: Megan G Osbourn
Adaptation to changing weather and economic conditions is fundamental to farm and ranch survival but this year's drought is pushing variable adaptation strategies to their limit. The international community is closely watching how this dire situation is progressing in California and on June 19th the Canadian Broadcast Company (CBC) visited the Sierra Foothill Research & Extension Center (SFREC) to document how ranchers are adapting to these extreme events and the implications these events have on agriculture and ultimately food production worldwide. Filming involved capturing interviews of three ranchers to explore their perspectives as well as a tour of SFREC to examine potential adaptation strategies to drought.
Joe Fischer, cattle rancher and President of the Placer County Farm Bureau, told CBC the economic impacts and emotional toll of the drought on ranching families have forced ranchers to rethink their management strategies and find innovative ways to manage the land. “Ranchers tend to be profitable if the land is productive,” Fischer said. “We have to look ahead five to ten years or more and try to be as conservative as possible with our stocking rates. Under these conditions, we have a much smaller margin for error so we have to be more precise than ever with our management strategies.”
SFREC Director Jeremy James and Livestock and Natural resource Advisor Glenn Nader used SFERC as an opportunity to demonstrate how intensive grazing management, agricultural by-products and culling strategies could be deployed to mitigate some of the impacts of drought. Many producers with limited feed sources are utilizing agricultural by-products that are available in their area in order to sustain the nutritional requirements of their livestock. Nader, pointed out that almond hulls are high in energy and have limited protein, which allows cows to more efficiently digest hay and can limit the quantity of hay they need to consume. Nader warned that the almond hulls fed must contain a low level of almond shell, in order to avoid problems with rumen digestibility. Rice straw and rice bran are more local agricultural by-products that, under the right conditions, have been utilized as dietary supplements for cattle.
To view the proceedings from the January 29th SFREC Drought Workshop, click here.
- Author: Dustin Flavell
Peak standing crop at SFREC for the 2013-2014 forage production year occurred on May 20, 2014 and yielded 2300 pounds per acre for the season. This is 77% of the historic average of 2971 pounds per acre. Ending the forage production season at 77% of average is better than originally predicted, considering the cold, dry fall and early winter , along with the historic low forage production through January.
Precipitation totals for the season came to 16.63 inches which is 56% of the historic average of 29.5 inches annually. Considering we received 12.5 inches of rain from February to May further shows that rain during the rapid forage growth season means more to overall forage growth than total precipitation. In fact, had we not had the very cold early December temperatures that immediately followed the 2.26 inches of precipitation at the end of November this forage season would have looked altogether different. Starting the rapid forage growth season at 98 lbs per acre instead of closer to our average of 515 pounds per acre is what most likely kept this from being closer to or better than an average forage season.