- Author: Nikolai Schweitzer
Yesterday Sierra Foothill Research and Extension Center staff employees participated in the 8th Annual University of California Walks Wellness event at the Yuba River Education Center. This UC-wide event is intended to develop, promote, and support a thriving culture of health & well-being in the workplace, with thousands of employees participating throughout the system. Our walk was organized by Staff Assembly Ambassador, Clint Tipton, who was joined by staff members at the river to exercise on the Douglas McCreary Nature Trail. UC WALKS is a UC Living Well program which promotes wellness & an active lifestyle by encouraging staff, faculty, and retirees to take just 30 minutes out of their day to walk with friends.
- Author: Nikolai Schweitzer
- Author: Nikolai Schweitzer
Sierra Foothill REC has been collecting and recording rangeland forage production data since 1979. Every year when rangeland forage production values are recorded, explanations as to the results of pounds per acre grown are based on past forage production values & statistics, plus a CIMIS weather station which resides at 660' elevation; whereas, the Forage Plot lies at 1470' and 1.3 miles away from #084 Browns Valley CIMIS Station. SFREC has recently installed replicated soil temperature sensors (5-10 cm in depth), soil water content sensors (5-10 cm, 25-35 cm, & 56-65 cm in depth), air temperature sensors, and a precipitation gauge. Two replicated soil sensor stations were each placed under canopy and in the open. Illustrated below are tables and graphs depicting rangeland forage production values and trends, newly installed soil sensor data (Open and Canopy), and a dramatic comparison (Forage Plot vs. CIMIS) in precipitation values.
There were two major developments during this rangeland forage production season (Nov 1, 2017 thru March 1, 2018). The first being that we had the highest level of forage production for the month of February (1637 lbs/ac) in our recorded history. The warm February we had may be a contributing factor to this. The other major development is the significant differences in monthly/total precipitation values between the CIMIS and the forage plot.
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- Author: Dustin Flavell
Samples taken in the SFREC's forage plot through the month of January (Clipped on Feb. 1) indicated 943 lbs/ac. This is 183% of the 34 year average of 516 lbs/ac. Our rain gauge indicates that we have received 28.14 inches of precipitation as of October 7th, only 0.3 inches shy of our total season precipitation average of 28.48 inches.
Will this productive start to the season mean a bigger peak crop? Perhaps not, looking at recent years that had similar germination forage values and similar forage production through January, this may not be the case. In the 2012-13 forage season (highlighted red) forage production through January was very similar. However, at the end of the forage growing season, peak standing crop was average. Looking at 2005-06 (highlighted yellow) there was a later first germination of November 7th, and near average forage production at 404 lbs/ac. It is more similar to this year, however, because the forage production through January was 983 lbs/ac, and that year ended with 139% of the average total season forage production.
In my 16 years of measuring production and reviewing the data, one thing is for certain. Predicting overall forage production in the early part of the growing season is difficult. Measurements taken in February, and even March, do not indicate a clear path as to how a forage production season will end up at peak standing crop. Click here to further explore over 30 years of forage production and weather data at SFREC. Looking at our production through April will certainly produce a clearer, more predictable picture of how this current year may end up.
- Author: Helen Dahlke
To overcome the problems that have plagued traditional tracer studies we have developed a new tracer concept that utilizes bio-molecular nanotechnology. We use short, artificially made DNA sequences that are wrapped into a safe, biodegradable polymer composed of polylactic acid (PLA) to protect the DNA from being eaten by microbes during the transport process. Because DNA is made of the four basic building blocks adenine (A), thymine (T), guanine (G) and cytosine (C) (Fig. 1), which can be combined in any random order, our unique DNA-based tracers allow, in theory, fabrication of an enormous number of unique tracers (approximately 1.61 x 1060) with identical transport properties. Because of their unique DNA sequence the tracers have unique IDs, thus, we can use multiple tracers at the same time in the same watershed. The amount of tracer present in a streamwater sample can be estimated with real-time quantitative polymerase chain reaction (qPCR), a method commonly used in molecular biology, which determines the number of DNA copies present in a sample. Finally, during the tracer fabrication process, we can alter the size of the tracer particles to anything from 200 nanometers (size of a virus) to 1 micrometer (size of colloids or bacteria), which helps mimicking the physical transport properties of the pollutant of interest.
In the next two years we will test differently sized DNA tracers in a well-studied, small experimental watershed at SFREC to test their use for identifying hydrologic flow pathways. This study will provide invaluable information for the understanding of processes in hydrologic systems that can be used to improve hydrological and biogeochmical models used to predict transport of pollutants from hillslopes to streams. To achieve this broader goal, we will distribute 5 different DNA tracers at 5 different locations at incrementally increasing distances from a trenched hillslope at SFREC and measure the tracer breakthrough curves in a runoff collection system and the watershed outlet. The injection locations will be chosen to represent a range of specific soil-landscape characteristics such as places with relatively deep soils, shallow soils and areas where flow visually concentrates in the landscape. With the tracer experiments we also hope to quantify preferential flow pathways (e.g. macropore flow) in the watershed. Preferential flow is hypothesized to lead to shorter travel times of water and pollutants through soils and the vadose zone. Because of the variable size of our DNA tracers (0.1-0.4 µm) they could be particularly useful for quantifying macropore and preferential flow because we expect that a small fraction of the tracers will be filtered out in the soil matrix while the majority of the DNA tracers will move along the most rapid flow pathways. The results from these experiments, if successful, will provide improved estimates of the time it takes for water and solutes to travel through the soil to streams, which will allow us to more accurately predict the risk of pollution of streams and surface water bodies during storm events.