Kimas Tejas Nursery
Petiole Testing Helps Sustainable Farming
There are some major differences in fertilizer practices used by conventional,
sustainable and organic farmers. In conventional agriculture you’ll find
that most of the farmers’ attention is paid to the NPK content of the
soil. That is nitrogen, phosphorus and potassium. Some of the more knowledgeable
and aggressive conventional farmers will also pay heed to other nutrients such
as calcium, boron and sulfur. Sustainable and organic farmers, on the other
hand, see NPK and these other nutrients as part of a bigger whole and attempt
to balance fertilization with soil amending and correct biology. The thinking
farmer, from either camp, will test his soil each year to determine the fertilization
and soil amendment needs. But there is another tool which the farmer rarely
uses. Petiole (sap) testing can tell the farmer exactly what the needs of the
growing plants are now and in the near future.
Petiole testing is a technique that chemically analyzes the soluble nutrients
in the sap of the leaf stem. This analysis predicts the future growth potential
of the plant. NPK can be measured as can the other nutrients like calcium, boron,
and magnesium. This “snapshot” of the current state of the soluble
nutrient affairs of the plant can guide the farmer in micromanaging the nutrient
availability to the plant. If a nutrient is lacking, the farmer can then make
decisions on how to correct the deficiency.
It works like this. A person trained in taking petiole samples goes into the
fields to pull the samples from the plants. The samples are taken from the same
part of the fields each week. The field sampling area should be no larger than
40-60 acres. From each area 30 to 50 of the proper petioles are pulled. These
petioles are then sent to a lab where they are chemically analyzed for the nutrient
content that was in the sap at the time they were pulled. An agronomist with
a thorough understanding of the chemical and biological interactions of the
soil/plant relationship interprets the data and makes recommendations to the
farmer on how to correct any problems.
Sometimes it is the simple application of the missing element. Oftentimes the
problem can be solved by correcting any chemical imbalances that may be taking
place. The soil test will determine if the element is in the soil. The petiole
test will determine if the element is being taken up by the plant. If it’s
in the soil but not in the plant then it’s not being made available to
the plant. This can often be corrected by increasing the biological activity
of the soil by feeding the biology with soil stimulators such as humic acids
or molasses. Another option is direct inoculation of the microbes themselves
with Aerated Compost Teas or bottled microbial inoculants.
Texas is fortunate to have one of the best labs in the country that does this
type of work. The Texas Plant and Soil Lab, located in Edinburgh, is owned and
operated by K. Chandler. In business since 1938, owner/operator Chandler acquired
the lab in the late seventies. He has been making fertilizer recommendations
for over 50 years. Chandler has realized that conventional agriculture is in
trouble. Over the last two decades he has been working to move large-scale agriculture
in a more sustainable direction. Working with conventional and organic farmers,
he advises both in the use of conventional, sustainable and organic production
practices. His soil or plant tissue test results come with both an interpretation
and a recommendation on how to solve problems, either sustainably or for those
that are Certified Organic. His experience, combined with proper soil and petiole
tests, is helping our farmers achieve maximize economic yields while maintaining
and building healthy soils.
While it may be hard for a farmer to go cold turkey and stop using conventional
methods of production today, the appreciation of what some of these organic
practices can lend the farmer is going to move them towards a more sustainable
tomorrow. Petiole testing gives the farmer another tool that he can use to make
informed decisions.
For more information, please see the Texas Plant and Soil Lab website at http://www.txplant-soillab.com/
Steve Bridges