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Chestnut Growers of America |
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FOLIAR ANALYSIS |
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STANDARDS FOR TRACE ELEMENTS CURRENTLY UNKNOWN During the June 17, 2000 Field Day the issue of foliar analysis was discussed. Anthony Boutard pointed out that we don’t know the base levels of trace elements required for a good producing tree. Without standards we can be applying too much or too little fertilizer and will not know it. Too much fertilizer may cause too much vegetative growth at the expense of nut production, and too little fertilizer may cause lower production levels of lower quality nuts. There was consensus agreement that we should all participate in a leaf analysis in August this year on a voluntary basis. Anthony Boutard agreed to compile the data and provide results to us. Leaf analysis has been used for many years as a means of determining nutrient deficiencies and as a way to establish fertilizer requirements. OBTAINING THE TEST KITS Leaf sample kits can be obtained from the OSU Central Analytical Laboratory at 541-737-2187, or by writing to them at: Central Analytical Laboratory Leaves should be collected in mid-August and sent immediately to OSU. A single sample should represent an area no larger than 5 acres and should be from a single tree. Mark or map each tree that you sample. USE HEALTHY GOOD-PRODUCING TREES FOR YOUR SAMPLE It was agreed that we want to sample trees that are producing well, and avoid those trees that show visible signs of stress or disease, or those which for whatever reason just don’t produce well. The goal here is to identify the element levels that contribute to the healthy tree. We will be looking at the macro nutrients (N, P, K, Ca, S), as well as trace elements or micro nutrients, to develop a good picture of the healthy chestnut leaf. Collect 10 leaves per tree, but only one per branch. Collect leaves that are free of any disease or other damage. Remove the leaves so that the petiole (leaf stem) remains on the leaf. All leaves should be picked from the middle of the current season’s terminal shoots of about average vigor. If your samples are contaminated with soil, spray, or other visible residues, wash them in a detergent solution and rinse with soft water. Wash them quickly (one minute or less) while leaves are still fresh, to avoid loss of nutrient elements. Remove excess moisture by blotting with a paper towel. Then allow the leaves to air dry. Fill out the sample kit’s information sheet completely -- all this information may be useful. Put the sheet, along with the dried leaves, into the paper bag furnished in the kit. Seal the bag securely and mail it to the lab at the address given previously. No other container is necessary. If you are submitting more than one sample at a time make sure to code them in some way that they can be identified by you when the results are returned. Samples will be analyzed for
nitrogen, phosphorus, potassium, sulfur, calcium, magnesium, boron, iron,
manganese, zinc, and copper.
The
lab will send a computer-printout to you with the results. Make a
copy and send it to Anthony Boutard. FOLIAR
ANALYSIS PROJECT PROVIDES BASELINE FOR "NORMAL" IN WESTERN
ORCHARDS Analyzing the nutrient levels in
the foliage of crop plants is a useful tool for determining fertilizing
needs and application efficacy, and assessing the general health of the
chestnut orchard. In order to
make sense of the foliar analysis, we must know the normal state of
affairs in a healthy chestnut leaf. For many crop plants grown in the western U.S., reliable tables of foliar nutrient content ranges have been established. Because chestnuts are a minor crop, the information has not been developed for the species in this region. There might be a temptation to use tables from another nut crop. However, neither walnuts nor hazelnuts are closely related to chestnuts; soil preferences are different, and the foliage of those trees is different in chemical composition. There are some sources addressing foliar nutrient levels in chestnuts, however they were generated in different soils and climates, and we need local analysis to refine that information. During this summer, several
chestnut growers volunteered to undertake an analysis of some of their
healthiest trees to help generate local nutrient level ranges for the west
coast. Leaf samples were
collected between the 8th and 24th of August.
All of the foliage samples were taken from young orchard grown
trees (less than 15 years). The first of the OSU reports we
received did not include any recommendations concerning nutrient levels.
Subsequent reports did because it was possible to observe patterns
in nutrient levels once the number of samples increased.
According to Nancy Kyle at the Central Analytical Laboratory, 11
samples were received in August, and two in September.
As of writing this article, only six of the samples analyzed at OSU
have been sent to me. I received four more prepared by Agri-Check, and two
were prepared by Californian labs. As an interim measure, the Central
Analytical Laboratory has adopted hazelnut recommendations for chestnuts. Approach these preliminary recommendations carefully.
For example, under potassium (K), some of the reports noted a
deficiency and suggested that adding lime may free up potassium in the
soil. It is important to
remember that the optimal pH range for chestnuts is between 5.0 and 6.0
(Crawford 1995: Bourgeois 1992, 252), and liming is not desirable if the
pH is shifted out of this range. According
to Breisch (1995, 155), chlorosis in chestnuts can result from an elevated
pH, which blocks the absorption of iron and other nutrients.
For both conventional and organic orchards, banding K-Mag at the
drip line is an effective method of increasing available potassium without
increasing the soil pH. Breisch (1995, 156 & 159) also
stresses the importance of boron and manganese for tree health and nut
production. When boron is
deficient, young nut bearing flowers of the Japanese chestnut (Castanea crenata) have been observed falling from the tree just
after flowering. In many cane
fruits and nuts, boron deficiencies are also associated with fruiting
problems. Boron has a role in
the synthesis of the bases that form DNA and RNA, and the movement of
sugars in the phloem. (Salisbury
and Ross 1978, 92) Breisch
notes that chestnuts are heavy consumers of manganese, which tends to be
abundant in acidic soils. Shattuck
(1991) notes that chestnuts tend to show signs of manganese
deficiency in soils where the pH exceeds 6.5.
Leaf tissue concentrations below 41 ppm were identified as clearly
deficient. However Shattuck
also observed deficiency symptoms at higher levels (55 to 100 ppm), though
other deficiencies, nitrogen and iron, made it difficult to clearly
interpret the results. All of
the reports we received showed manganese levels in good shape.
Table 1 below provides the raw
results of the individual tests in percent or parts per million dry
weight. Table 2 reports
various published dry weight composition ranges from other regions.
Table 3 is a statistical summary of the data in Table 1.
I have confined summary in Table 3 to the Washington and Oregon
results. We have only two
reports from California, and those orchards are growing in unique
situations. Those samples
were collected and tested in 1999. At this point, we can ponder the
range of values collected, and evaluate them against published levels
reported in Table 2. The next
formal step in this project falls to Jeff Olsen, OSU Extension for nuts,
who will take the results of the effort and create a range from deficient
to excess for the various nutrients, and then formulate chestnut specific
recommendations for addressing deficiencies.
I want to thank those who took the
time to sample their trees and send me the analysis results.
I am very also grateful to Sandra Anagnostakis for her quick offer
of the Shattuck and Miller papers, which are helpful. References:
Bo Table
1. Foliar nutrient content
for western chestnut trees in terms of percent (%) or parts per million (ppm)
of dry weight.
Notes: 1.
The first three samples are from certified organic farms. Table
2. Published descriptions of
foliar nutrient levels in terms of percent (%) or parts per million (ppm)
of dry weight.
Table
3. Statistical summary of the
Oregon and Washington results
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Copyright 2009 Chestnut Growers of America, Inc.