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Flowers are blooming, the rains have come (and hopefully not gone yet), and a new growing season has begun.  Spring is a good time to sample soils for nutrients as well as assess the efficacy of winter leaching programs, however please remember that the rainy season is not over yet, and any additional rains will continue to remove mobile nutrients such as nitrate and sulfate.  Soil samples should not be so wet that they have to be poured from their sampling bag; if you can squeeze water out of your sample, let it air dry for a few days before submitting.  Waiting until the ground is dry enough to sample will also protect soil structure and reduce compaction. 

When sending in plant tissue samples, if the leaves are not fully expanded, our ratings may not adequately reflect plant nutrient status.  While it may be tempting to get a head start on the season, for the best results follow our foliar sampling procedures, located in the ‘Plant Analysis’ section of the ‘Analytical Services’ tab.

Additionally, there is often confusion regarding our petiole tests versus full leaf tests.  If you want our ratings you should not be selecting a PT2 package for petioles, unless you are submitting grapes.  Please refer to the sampling procedures to see what test you should select, as it often varies with crop.  Nutrient concentrations differ between petioles and leaves, and most of the PT2 data we have is for leaves.  If in doubt about what test to choose, or the difference between a leaf, blade, and petiole, call in and ask!

Almond harvest is wrapping up.  If you have not already submitted your hull samples, now is the ideal time to do so.  We offer ratings on just boron (PT 26), as well as the PT2 and PT4 tests.  Hull samples can be selected earlier in the year, at hull split, or at harvest, and they should be collected while nuts are still on the tree, not from the ground.  Once hulls are on the ground they will become contaminated with soil, as well as anything that may have been applied recently.  As we cannot wash almond hulls without losing sample integrity, anything that the almond hulls become contaminated with will not be removed before analysis.

It is not uncommon for hulls to be collected at harvest and submitted weeks to months after.  While we understand that harvest is a busy time, we request that you submit samples as soon after collection as possible.  This is to ensure sample quality.  If hulls start to mold, which is often the case, it can compromise the sample and give inaccurate results. 

We have made some changes to our soil test offerings.  Unfortunately we will be discontinuing the soil infiltration tests for the time being, as it is a test that is best performed in the field, rather than on disturbed soil.  We will also no longer be conducting ‘disturbed’ bulk density.  While we will continue to offer the test, all bulk density samples must be submitted in a core of known (or easily determinable) dimensions, or with the core volume provided on the submittal form.

Happy harvesting!

Fall is here, and it is time to start looking at residual nitrogen, as well as any sodium, chloride, and boron that may have accumulated in soils.  Forecasters predict a wet winter due to El Nino, and while it is unlikely to end the drought, we can hope that it will alleviate some of the severity.  Winter is an excellent time to leach accumulated salts from soil due to low evapotranspiration and (hopeful) rains.  If you know you have a problem with salt build up in your soil, the S10C package, which contains our complete fertility analysis plus the saturated paste package, will tell you how much sodium, chloride, and boron is in your soil. 

Additionally, please remember that when leaching, the final salinity of the soil depends on the quality of the water you are leaching with!  If using irrigation water, we suggest our W2 package, which provides sodium, chloride, and boron, as well as the sodium adsorption ratio.

We still offer our plant analyses packages over the winter, the most popular being the PT2.  Please be aware, however, that many of our ratings, especially for permanent crops, do not always apply to tissue samples this late in the year.

If you are interested in other analyses, please view our ‘Analytical Services’ section, or call and ask.

Have a prosperous season!

It’s November – the beginning of the ever lengthening holiday season, and for many of our growers, fall soil sampling.  It’s a good time to assess the amount of soil-immobile nutrients such as P and K, as well as soil pH and any possible buildup of sodium, chloride, or boron.  We offer multiple packages that assess the amounts of these nutrients in the soil, the differences of which I am frequently asked by customers to explain.  These packages are the S3C, the S10C, and the S10P.  As the S10P is fairly rare and mostly developed for use in the turf industry, I will briefly discuss it at the end of this post. 

For the most part, the S3C is adequate for assessing nutrient availability and the buildup of adverse salts in the soil.  The exception to this is boron – the DTPA-sorbitol extraction that we perform in that test is better at judging whether the nutrient is deficient rather than toxic.  It will certainly alert you to high levels in the soil, but not whether they will be toxic to your plant.  This is because the tests in the S3C are designed to look at what’s currently available to your crop as well as labile nutrients, which are nutrients that can become available.

If you have been irrigating with water high in salts, or know that sodium has been building up in your soil profile for a few years, it can be helpful to get the S10, or S10C.  The S10 is the soil saturated paste test used for assessing soil salinity, and the S10C tacks on the complete fertility package, the S3C, at a higher cost.  The difference between the saturated paste extract and the S3C is that the reagent is water, so it only extracts what is in the soil solution or held loosely enough to be pulled out with water. 

The S10 and the S10C will give you the sodium adsorption ratio (SAR), which will assess how much of an effect sodium has on the soil by comparing the amount of sodium to the combined amount of calcium and magnesium.  Sodium will start negatively affecting the soil at a SAR of 5, and is classified as sodic above 13.  This simply addresses the structural effects that sodium has on the soil; it does not take into account the toxic ion effects, which are crop specific.

The next question I always get is: should I get the S3C or the S10C?  My response is based on these questions that you can ask yourself.  Do you suspect or know that you have an issue with sodium, chloride, or boron based on previous soil tests, your irrigation water tests, or your plant tests?  Or, are you having a problem with water infiltration?  If the answer is yes, then you may want to consider the S10C.  If you’re not sure, you can always start with the S3C, which will let you know how much of the CEC is taken up by sodium.  If you have high chlorides or boron in your water, or have fertilized with potassium chloride, you can add on chloride or the saturated paste boron test, which will be cheaper than the entire S10C. If you find from the S3C that you need the S10C, you can always resample, or ask for us to add on the SAR. 

An extremely important caveat to note for the S3C is that the calculated cation saturation percentage can be incorrect if your soil naturally has or if you have applied gypsum or lime – their presence in high amounts will artificially reduce the calculated exchangeable sodium percentage.  So, if you fit into those scenarios, you will need to get the saturated paste test.

The S10P has been developed to assess the availability of nutrients that are already in the soil solution or extremely easily released, but not those that are in the CEC or bound onto soil particles.  We cannot give recommendations on it, but it will allow you to assess what’s readily available to the plant.  It is not an accurate assessment of soil P availability, however, since a very tiny fraction of it remains in soil solution even in soils well supplied with P.

As always, if you have any further questions, you can speak to the agronomist.

Happy Growing!