CFBF. 2009.  Nitrogen (N), potassium (K), boron (B) and zinc (Zn) are the fertilizer nutrients that most often deliver improved almond tree health and/or yield in California.

The following are key points to effective, efficient fertilizer practices for these nutrients in almonds:

• Tree N demand drives N uptake. In mature orchards, crop load drives demand. Match your annual fertilizer N program to estimated orchard yield for that year.
• A 2,000 pound nut crop uses roughly 100 pounds of N. To get 100 pounds of nitrogen into the tree, apply in the range of 200 pounds to 300 pounds of N to the active root zone under trees. Active feeder roots grow in moist soil. Fertigation is the most efficient way to deliver N fertilizer to the soil.
• Time fertilizer N application to match periods of high tree N need. April-July is when nut growth is most rapid.
• Sample leaves for nutrient analysis in every block, every year. July leaf sampling is the best monitoring tool that UC knows right now. Break blocks into smaller management zones if you see yield differences and can manage subzones in the block to maintain good overall yield for less fertilizer cost.
• Individual tree July leaf N level of 2.2 percent means adequate tree N. Use 2.5 percent leaf N as the target in a block or orchard, so no trees in an orchard are deficient.
• Individual tree July leaf K level above 1.4 percent means the tree has adequate K nutrition. A leaf sample target of 2 percent leaf K should avoid K deficiency anywhere in the block.
• Potassium deficiency this year means reduced flower numbers and crop next year. Timing of highest tree K need is April-July. Spring fertigation is the most effective application practice. Use fall banding of fertilizer K in flood or solid set sprinkler irrigated blocks.
• Foliar applications in the fall or spring are the best practice for getting zinc into trees.
• June leaf Zn levels below 15 parts per million are deficient. Target block leaf levels between 15-20 parts per million Zn.
• Boron is an essential plant nutrient, but can be toxic at high levels. Sample hulls for boron analysis at harvest. Adequate hull B is 80-120 ppm. Adequate July leaf B levels are 30-80 ppm for a single tree.
• Bloom is the key time for good B levels in almonds. Fall or pink bud are the best times for boron sprays. Full bloom boron foliar spray may reduce yield. Gradually increase B fertilizer rates if you are not satisfied with your current program. Excessive B fertilization can dramatically reduce yield.

IPNI.  Spring 2011.  Cotton has made quite a comeback over the past few months with steep, and at times extreme, price increases in 2010. Prices are expected to remain relatively strong through 2011 as stocks should be tight. As a result, cotton acres may increase in some regions this year. A major factor affecting both cotton yield and quality is the availability of adequate and balanced nutrition. Given the optimism, now is a good time to review some cotton fertility basics.

Nitrogen is essential for the development of shoots, buds, leaves, roots, and bolls. Cotton takes up about 60 lb of N for each 480-lb bale produced, though it should be noted that N uptake figures can vary. Uptake is limited early in the season prior to squaring, and the majority of N is taken up after fi rst bloom. Therefore, split applications of N improve the chances of meeting the crop needs during peak demand periods. A general recommendation is to provide about 10 to 20% of the crop N needs before bloom, and apply the remainder during the boll development period. Texas Tech University research has shown that on the Texas South Plains about 5 lb of N would be required per inch of water consumed. Since cotton is an indeterminate perennial, too much N late in the season may cause excessive vegetative growth and should be avoided. Soil and petiole tests can be helpful in determining preplant and midseason N management.

Phosphorus is important in early root development, photosynthesis, cell division, energy transfer, early boll development, and hastening of maturity. About 25 to 30 lb of P2O5 is taken up per bale of cotton produced. Placement of P fertilizer is not as important as in the production of some other crops. However, banding P can be advantageous in some situations (e.g., reduced or no-till, compacted soil conditions). Insufficient P results in dwarfed plants, delayed fruiting and maturity, and reduced yield. Use soil tests to determine optimum P application rate.

Potassium is an especially important nutrient in cotton production. It reduces the incidence and severity of wilt diseases, increases water use efficiency, and affects fi ber properties like micronaire, length, and strength. It is important in maintaining sufficient water pressure within the boll for fiber elongation. Cotton utilizes about 60 lb of K2O per bale. The need for K increases dramatically during early boll set, and about 70% of uptake occurs after first bloom. Potassium deficiency may be expressed as a full season deficiency, or it may not appear until late season since this is the period of greatest demand. A shortage of K reduces fiber quality and results in plants that are more susceptible to drought stress and diseases. Preplant applications of K fertilizer, and in some cases mid-season foliar applications, are effective in correcting deficiencies. Soil testing is the first step in predicting K needs.

Secondary elements and micronutrients may also be critical to profitable cotton production. For example, cotton responds to trace elements such as zinc and boron where these nutrients are deficient. Soil tests, plant analyses, field history, and experience should be considered when establishing the need for these elements.

Good nutrient management results in higher cotton yields, improved fiber quality, greater water and nutrient use efficiency. So, in this year of optimism make sure that fertility doesn’t limit cotton production.

NOTE:  For complete and accurate usage and benefits of gypsum (calcium sulfate dihydrite) and andydrite (calcium sulfate), please go to the “Publications” tab on this website and review our published articles on the subject.  For more complete information on gypsum/anhydrite usuage and/or recommendations, and how calcium sulfate can benefit your own farming operation, go to  the “Contact” tab and email or call us. 

GrowingProduce.  7 March 2011. Gypsum (calcium sulfate) as a soil additive is widely advertised, but not well understood, according to Emily Sneller, Michigan State University Extension soil fertility educator. Sneller offers a quick reference list about gypsum to help growers determine whether they should be adding it to their soil:

Gypsum is not lime.
- In order to adjust soil pH, liming products must contain carbonate (CO3-), which reacts with hydrogen ions to neutralize soil acidity.
- Gypsum is calcium sulfate (CaSO4). While the calcium will displace hydrogen ions, these ions will remain in solution and will not adjust soil pH.

Gypsum can be used as a source of calcium and sulfur. However, remember:
- Gypsum is more soluble than lime and can add calcium more rapidly to the soil. This may result in decreasing potassium or magnesium levels in the soil. Monitor this by soil testing.
- Michigan soils generally are calcareous-based soils, meaning they are derived from materials high in calcium, resulting in soils naturally higher in calcium.
- Gypsum can be used as a sulfur source. However, it tends to be less soluble than other sources, such as ammonium sulfate.

Gypsum can improve water and root infiltration in sodic soils.
- Sodic soils are very uncommon in Michigan.
- Sodic soils are high in sodium, low in calcium, and have problems with water and root penetration due to the effects sodium has on structure.
- The calcium in gypsum, along with drainage and tillage, has been shown to reduce sodium levels in sodic soils.
- Reduced sodium levels will improve soil structure, resulting in greater water and root penetration in sodic soils.

Gypsum has been shown to be effective at treating aluminum toxicity on soils with a pH lower than 4.5
- At pH lower than 4.5, aluminum in soil overpowers the ability of hydrogen ions to increase pH.

Sulfate may act as a counter ion on soil particles, increasing aluminum absorption from the soil solution. Aluminum sulfate is less toxic to plants than the aluminum ion individually. Emily Sneller, MSU Extension.

IPNI.  Spring 2011.  Potassium fertilizer (commonly called potash) is mined from underground deposits in many parts of the world.  Canada is the largest producer of potash fertilizer, followed by Belarus, Russia, and China.  The potash ore is extracted from depths exceeding one-half mile below the earth’s surface.   The ore is first crushed and washed to remove any clay or minerals that may be present.  Some potassium ore contains iron that imparts a red tint to the final fertilizer.  The sodium salts are then separated and removed from the potash.  The potash particles are then compacted to achieve the desired size for convenient handling and spreading.

A few naturally occurring surface-water brines (such as the Great Salt Lake in Utah and the Dead Sea bordering Jordan and Israel) contain sufficient potassium to make potash extraction feasible.  Solar evaporation is used to concentrate the salts, which are washed to separate the potassium salts from the sodium salt.

ScienceDaily  — Even in the animal world, mating is so desirable that the nematode worm will change its sex to increase the chances of partners—a groundbreaking discovery of nurture changing nature, says a University of Alberta scientist, part of a that which conducted the research.

“We all know that we can alter our behaviour, depending on the environment in which we are raised,” said Dr. David Pilgrim, from the U of A’s Faculty of Science. “But it was thought that our basic genetic makeup is unaltered by these effects. What we have now shown is that our nature—our genes—may be altered by our nurture, the environment.”

Pilgrim, Dr. Veena Prahlad and Dr. Elizabeth Goodwin have published their results in the prestigious international journal, Science. Prahlad was a post-doctoral student in Pilgrim’s lab before moving to the University of Wisconsin, where she completed the work in Goodwin’s lab.

Like humans, the female nematode worm bears XX chromosomes but the male nematode has only a single X. The team showed that the sex ratio—percentage of males and females—could be altered depending on the amount of food the animal senses. While the young female is still too young to display any sexual characteristics, it judges how much food will be available once it grows up. If it thinks there will be a lot of food available once it is sexually mature, a significant number of XX animals will lose one of their X chromosomes—making them genetically male. If they think that food will be scarce, they will keep both their XX chromosomes and grow up to be female.

Also, the female–actually a hermaphrodite since it can produce sperm as well as egg—can self-fertilize if she doesn’t find a male but the offspring then are only female (XX).

If the population density is high, as it would be near food, then there is a benefit to being a male since the male nematode is rarer and the chances of finding a potential female partner are higher. If it is low, then the worm is safer being a female since she can still have offspring even if she never meets another animal.

“The trick comes in being able to estimate whether the food will be plentiful or not when it is ready to reproduce, because it needs to make the decision to be male or female well before that,” said Pilgrim. “This research helps understand how animals adapt to a variable environment, and to a certain extent, why sex exists.”

IPNI. March 1, 2011 – Norcross, Georgia, USA – With the cooperation of more than 60 public and private soil testing laboratories, the International Plant Nutrition Institute (IPNI) has completed a summary of results of tests performed on approximately 4.4 million soil samples collected in the fall of 2009 and spring of 2010. The 2010 summary contains information about phosphorus (P), potassium (K), sulfur (S), magnesium (Mg), zinc (Zn), chloride (Cl-), and pH. “The summary can be viewed as an indicator of the nutrient supplying capacity or fertility of soils in the U.S. and Canada,” notes Dr. Paul Fixen, IPNI Senior Vice President and Director of Research. He coordinated the efforts of IPNI North America staff and others in collecting the data and compiling the report. The 2010 summary is probably the most comprehensive evaluation of soil fertility ever conducted in North America.

The new summary offers a snapshot view of soil test levels in the U.S. and Canada in 2010, but also provides a comparison to the previous two summaries which were completed in 2005 and 2001. Since the 2010 summary is the third in which laboratories were asked to complete frequency distributions of soil test results, temporal changes in soil test level distributions can be viewed for the second time for states and provinces.

The 42-page publication (Item # 30-3110) is available for purchase for USD 25.00. An accompanying CD-ROM contains a PDF fi le showing the pages of the report, a PowerPoint file of all figures and graphs in the report, and an Excel workbook of the major tables to facilitate construction of custom graphs for regions of interest. The CD alone (Item # 82-3110) is available for USD 10.00. The combination of the publication plus the CD (Item # 90-3110) is available for USD 30.00. Shipping and handling costs are added.

For more information or to order, contact: Circulation Department, IPNI, 3500 Parkway Lane, Suite 550, Norcross GA 30092; phone 770.825.8082. E-mail: circulation@ipni.net.

Potassium helps crop plants resist disease organism invasion or penetration by strengthening cell wall structure. Plants having adequate K will have thicker cell walls compared to plants deficient in K. This makes it harder for disease organisms to penetrate plant cells and establish an infection. This applies to fungal, bacterial, nematode, insect, and viral disease organisms. Another indirect benefit from stronger cell walls is that plants are less prone to lodging, and stem and leaf architecture is more upright and spread out, thus improving airflow through the crop canopy. This can help slow down the spread of any disease organism through the crop canopy, and result in lower humidity levels that can reduce the growth of pests and diseases that prefer moist environments.

Potassium is also vital for water regulation in plant cells. There are two mechanisms of water regulation that help plants better resist disease establishment. Potassium is important for stomate cell regulation for pore openings on plant leaves. Adequate K nutrition will allow the plant to maintain smaller stomatal openings compared to a K-deficient plant, and also pores are opened and closed more easily and timely, which helps limit the successful invasion of disease organisms into plant leaves. The second water regulation mechanism that can help reduce disease organism penetration into plant cells is that adequate K nutrition helps the plant to maintain increased turgor, or water pressure in cells. A cell with optimum turgor pressure will tend to push organisms away from the cell membrane when the invading organism attempts to push through the cell membrane.  [Thomas L. Jensen]