Spring Root-flush

 

Spring Root-flush

Winter dormancy is an important development stage in the tree growth cycle. During this time period crops rest and recharge for the upcoming growing season. Both cold air and soil temperatures are required to supply much needed “chill hours” for resting trees. “Chill hours” are a lot like REM sleep to you and me. REM sleep is the nightly deep-sleep that is vital for keeping us healthy and well rested upon awakening. Simply put, trees need cold temperatures to slow (or stop) their growth activities. When temperatures are too mild, trees do not receive adequate “chill hours” and break dormancy in an energy-deficit condition. In other words, trees don’t sleep well and awaken stressed.

 

 

Spring root-flush:

In California, normally happens with prunus species like almond, early peach, plum, nectarine, apricot and cherry varieties, in the 3rd to 4th week of January. This activity begins when soil temperature (in top 2-4”) reaches 45°F and precedes bloom by approximately three weeks. Buds visibly swell with water and nutrients. The new hair-root growth is needed to support the upcoming crop with water and nutrients. Once root-flush is underway, growers should take advantage by beginning fertigation or soil fertility applications. Nutrient focus should be on root health and crop support.

 

Temperature:

Soil temperature is a major driving factor in the onset of spring rootflush. Currently, soil temperatures, in California are 50-52°F (well above 45°F) due to the high volume of rain (4-5”) that has fallen in the past four to five weeks and continues to saturate much of the state. California has another 4-6” of rain forecast in the next week. Due to this increase in soil temperature, rootflush is now underway.

 

Chill hours:

http://fruitsandnuts.ucdavis.edu/Weather_Services/chilling_accumulation_models/Chill_Calculators/?type=chill  [Check your current chill hours]

Another concern is that “chill hours” are below normal for early January and trees are not getting the rest they need. Rootflush is underway and therefore so is root respiration. Respiration is the plant process of “burning up” or releasing stored nutrient energy for plant use. This is a problem because new roots are using up nutrient energy that is meant for the upcoming bloom.  Due to these circumstances, an energy deficit is beginning that cannot be restored from dormant rest. If you enter the bloom stage in an energy deficit (stressed) condition, it will affect the plant’s ability to pollinate, set and “stick” crop. One symptom of bloom stress is “June drop”. Plants self-regulate by aborting excess crop to ensure they do not run short on nutrients. They are programmed to know how much crop load they can support based on their health and availability of nutrition.

 

Feed the Soil:

When short on “chill hours”, the next-best alternative is to supply energy to the plant via “plant-ready” nutrition. Treatment emphasis should be on the soil, since the roots are already at work. Using an orthophosphate source provides much needed “plant-ready” phosphorus for root growth and health. A unique root benefit is a fungicide-like response within the rootzone. This is especially important in waterlogged conditions. Unlike polyphosphate fertilizers, orthophosphate is not temperature dependent. This means it is readily absorbed by new roots in cold soil temperatures (<63-68°F). In addition to feeding the soil, this is also an ideal time to re-inoculate the rhizosphere with soil microbiology. The more diverse your soil microbiology, the better your soil-nutrient and water efficiency you will experience. Dr. William Albrecht said, “We must not forget that microbes are what make a living soil ‘alive’…microbes, eat at the first sitting…Plants eat second. Plants and microbes must be in symbiotic activity and not in competition for fertility if our productive soils are to be maintained.” So, how productive are your soils? As the farmer, it is good stewardship to know and make necessary adjustments to nurture the soil and ensure it is still productive for the next generation.

Here’s to your success!

 

 

 

 

 

 

 

Almond bloom: A very important stage in the life of the crop; one filled with anticipation and trepidation. At this stage, growers work to get pollen (from the Anther; male part) in contact with the Stigma (female part) by various means.

The Science: Almond bloom is beautiful sight to see, but don’t think it is just for our enjoyment.  Almond trees’ primary objective is to propagate the species into the next generation. Blossoms are the “lure” plants use to attract pollinators. At the same time, plants’ physiological activities run at a feverish pace with time, temperature and weather all contending against the plants pollination efforts. The process, while orderly, behaves a lot like a Rube Goldberg device, due to the many intricate, interdependent activities involved. For example: When a pollen grain connects with the stigma, it is considered “pollinated” and starts the Pollination process. Next begins the “fertilization” process: The pollen tube elongates (while the sperm travels along it simultaneously) down the length of the Style to the ovary where it attaches to the ovule allowing the sperm a chance to fertilize the egg and form a Zygote. This process requires a large amount of energy from within each pollen grain. Every pollen grain contains both sperm and tube cells and the health and viability of the pollen is directly related to the nutrition available to the plant. There are many factors which can affect the almond bloom period. These are called “stressors”. Stressors are a problem, because plants must manage them, in addition to normal activities, at each stage of development. Some examples are Environmental (Temperature, precipitation, etc.), Cultural (Nutrition, irrigation, etc.) Biological (fungal, pest pressure, etc.). Without a plan, these can all significantly ill affect your crop’s yield potential. 

 

Practical application: At the start of the bloom stage, there is an internal plant “tug-of-war” between a large volume of plant “dormancy” hormones and the introduction of “reproductive/bloom” hormones.  As the tree awakens, it is thirsty (dehydrated) and hungry (energy deficit) from the dormancy period. Think of it like a grizzly bear awakening from hibernation; the bear’s top priorities are water and food, because much of its reserves were depleted while sleeping. Almond trees are no different. As a grower, you can take an active role in these needs. This is where a fertility plan can benefit you by increasing not only your orchard’s health, but yield and profitability. Let’s take a look at each of the stages of bloom and where your nutrient focus should be and why.

 

Green bud: Flower buds are swollen and green plant tissue is exposed, but no blossoms are yet visible. This is due to hair-root activity which has already been underway for 2 to 3 weeks. Roots are actively foraging for food and water supplies in preparation for the upcoming bloom event. Start fertigation plans now, with nitrogen and “plant-ready” orthophosphate for strong root support.  Application rates should be based on soil texture, to avoid over-applying for the soil’s capacity and plants’ needs. Why orthophosphate? When soil temperatures are under 63-65°F (top 6” of soil), phosphate (P2O5) is still soil-bound (especially in calcareous soil types) and not yet available for feeder roots’ use.  “Plant-ready” orthophosphate (H2PO4- or HPO42-) is not temperature dependent and therefore immediately usable by the roots, in cold soils. After dormancy, the root system and crop set are limited to the amount of stored nutrient energy available. This critical development stage is much like the start of a race and stumbling is not an option. Why take the chance of running short on nutrient supply? It is a Good Management Practice (GMP) and a major benefit to fortify roots and restock the root-system with phosphate, for the high energy demands that bloom puts onto the entire plant system.

 

Pink bud: Without a bud, you can have no bloom. Without bloom, you can have no almonds. Plant energy is vital for a good bloom. At this point, buds have been swelling up, growing rapidly. Nutrient application focus should now shift from fertigation to foliar feeding. While there is not yet a leaf in the field, there are on average, 75,000 to 150,000 blossoms per tree and each is rapidly drawing on stored plant energy reserves, which cannot be supplied via the root system, in cold soil temperatures. Applying “plant-ready” foliar nutrients directly to these plant parts, requires low per acre rates and provides nutrients/energy to supplement the demands of the pollination process. Foliar applications supplement the developing crop while soil temperatures warm and then begin soil-nutrient release for root uptake.

 

Full bloom: This is one of the most effective times to directly increase crop yield potential. When blossom pollination happens it triggers the fertilization stage. This is a time of massive energy demand. When fertilization occurs, almond kernel cell division starts. Under normal conditions, this takes 23 to 27 days to complete. However, it is directly affected by temperature and nutrient availability; warmer than normal temperatures accelerate (shorten) the cell division “window” and cooler than normal temperatures extend this process. Applying “bio-available” nutrients delivers energy and food, at this critical stage of crop development. In simple terms, more cells per kernel equals more weight per kernel at harvest. Remember, this is also a period when the plant is susceptible to infection through the blossoms and steps should be taken to avoid disease flare ups. Applying foliar orthophosphate helps plants build their own defenses for better health and disease resistance.

 

Petal fall: At this point, almond kernel cell division continues to occur at a very rapid rate. Soil temperatures are still cold (<63-65°F) and foliar feeding is an efficient way to supplement plant and crop nutritional needs. Time is of the essence here as the plant will soon begin to shift the growth emphasis from crop-set into canopy-development. Feeding focus should now be on the developing nutlets and canopy. Crop retention is vital to profitability and photosynthesis from a healthy canopy plays a major part from now and until harvest time. Almond trees instinctively know how much crop they can support based upon current stored energy reserves. Remember, a plants primary objective is to perpetuate the species into the next generation and trees will not set more crop than can be matured. When trees run short of energy during bloom, they will begin to self-regulate at Petal-fall stage, by aborting nutlets. This is a time to be very aware of the orchards growth response and be ready to make rapid GMP fertility decisions, as needed. The crop won’t wait for you, so be readiness is crucial!

 

40-45 days Post-Full bloom: Soil temperatures are normally still below 65°F, so you won’t yet be benefitting much from soil-fixed nutrient release. Foliar applications will still be very useful and should focus on boosting canopy health and vigor. Photosynthetic production and efficiency are crucial to get the plant feeding itself as early as possible. If you notice a weakly growing canopy, just after Petal-fall, it can be an early indicator of a heavy crop set (See everything you are looking at!). The tree could be sending extra nutrition to developing nutlets due to positive fertilization activity. Tissue sampling should happen once mature leaves are visible. Use the tissue results as a treatment guide for making fertility decisions. Don’t guess at what your orchard or crop needs.  At this stage, fertility applications are building internal solids (oils) for more kernel weight. Total Soluble Solids (oils) are heavier than water and will not evaporate when you dry down the orchard before shaking. This stage lasts (April 15—June 15) approximately 60 days. Fertility plans should include fertigation and foliar feeding with emphasis on nitrogen, potassium, calcium and traces as needed.

               

Here’s to your crop’s success!

For more information contact me via direct message.

Photosynthesis - 101a

Photo credit: Marc Suderman

Photosynthesis – Everyone, everywhere benefits from plants; specifically from Photosynthesis. It’s the plant process that takes water (6H₂O), carbon dioxide (6CO₂) and sunlight (energy) and transforms them, into glucose (C₆H₁₂O₆) and oxygen (6O₂) during daylight hours. This supplies food for plants and oxygen (and food) for the rest of us. It is the most vitally important activity on earth.

Approximately 95% of all plant structures are made up of carbon, hydrogen, oxygen…95%! These are taken from the air via the photosynthetic process. While this is a plant activity, it is dependent upon a living, nutrient-rich soil for supplying water and the necessary mineral nutrition, which cannot be gotten from the air. The mineral nutrition is the part where we have a direct effect; the 5%. To make this dynamic system work well requires “give-and-take” action. There’s a symbiotic relationship between plants and soil (biology). Plants need what only the microbes can provide and are unable to get for themselves and vice versa. Plants make sugars and soil microbes eat sugars. Soil microbes liberate soil-bound minerals that plants cannot release, but need for survival; interdependence. Of the sugars produced, plants use ⅓ of these photosynthates within the canopy and the remaining ⅔ are sent down into the root system. This is a win-win arrangement. The more diverse and active the rhizosphere (the area surrounding plant roots where microbes live), the more the food demand will be, but this also means there is more reproduction too. This will improve nutrient translocation for better plant health and therefore higher glucose production for better rootzone health. This creates, in effect, a perpetuating action between soil and plant.

Plants are made to be in the sun. They are designed to absorb sunlight and the heat that comes with it. Summer brings plenty of sunlight and higher temperatures. A healthy canopy should provide food and protection to the developing crop, but sometimes there are limitations to the canopy’s effectiveness. These can be a challenge at critical stages of development and can cause problems for growers. A good understanding of the key growth stages for your crop is important. This can help you better plan for potential stressors, like weather, drought, bloom, fruit set, fruit fill, etc. Designing a fertility plan for the nutrient demands of growing crops (before they need them) and emphasizing key nutrients, like phosphate, magnesium, iron, boron, manganese, etc. to lessen plant stressors and promote better plant/soil health via the photosynthetic process, is in your best interest. Dan Skow wrote, in Mainline Farming for Century 21, “In photosynthesis there is one limiting factor, in putting sugars into plants, namely phosphate...” For instance, excessive light and heat can cause plant stress. The Stress is not the problem, but a symptom of the Problem, namely nutrient deficiency. Considering every nutrient, with the exception of nitrogen, enters the plant in phosphate form, shows how key a nutrient this is to overall plant health and function. In calcareous soils, this is a challenge. Adding specialized soil microbiology will provide an ample soil phosphate supply and plants respond by building larger, thicker, hardier leaves that are better suited to care for themselves. These are plants’ solar panels and the better they are equipped for “catching” sunlight, the better the sugar production. “The number of layers [in the mesophyll] varies, principally due to nutrition. More layers mean a thicker leaf, more photosynthesis, and more crop.” wrote Dr. Arden B. Andersen in Science in Agriculture. Thicker leaves have a larger storage volume and higher solute (sugars) content. As a result, this gives a plant more resistance to rising ambient temperatures and helps to regulate its internal temperature better. This also allows the guard cells of the stomata to remain open longer into the day before shutting down to conserve water. More photosynthetic production yields more energy and more energy equates to more plant health. It takes healthy plants to grow nutrient-rich food. The crop produced can be nothing more than the “nutrient-template” provided it from the diet of the parent-plant; “Garbage in, garbage out” or “You are what you eat”. Making assumptions about the soundness of your fertility plan without verifying with timely tissue testing can prove to be costly. Growing high quality fruits or vegetables doesn’t just happen. It’s a lot like trying to hit a moving target. It requires a good plan and execution to get good canopy efficiency. The opposite is also true, if anything occurs to limit a plant’s ability to absorb sunlight and build photosynthates. I mention this because; summer is a critical time for fruit bud development which happens concurrently with all other plant operations and can place added energy/nutrient demands, onto a plant. Deficiencies, at this stage, can ill-affect production for the coming year. Remember, the higher the photosynthetic efficiency, the better equipped a plant is to address all plant issues. This includes generating high quality crops and higher quality equals better ship-ability and shelf-life. But, to do this takes energy (sugars). Plants “bundle” sugars to form primary and secondary metabolites. It takes ten times more energy to produce secondary plant metabolites than glucose. Without secondary metabolites, strong, high quality, nutrient dense fruits or vegetables are not possible. This is directly dependent upon how well plants photosynthesize. Bottom line: When plant glucose production fails to meet plant demands, crop quality suffers. Don’t let this happen to you!

 

 

Photosynthesis, on the surface, can be assumed to be nothing more than the plant activity of absorbing sunshine and growing. But, it is a very complex process; one that works for you, but can be limited or benefitted by your fertility plan, both in the soil and the plant. Nutrition has a major influence on crop yield, plant health and soil response. Fertilizing a crop, with good intentions doesn’t guarantee good results. Regular and timely tissue and soil testing are useful tools for tracking your growing progress. Fertilizers and lab testing cost you money, but so does delivering a crop that has sub-par quality, size, color, brix, firmness, etc. on your bottom line. Utilizing test results to make timely nutrient decisions is good stewardship. Good stewardship is also making sure your plant’s canopy is functioning at a high level of efficiency to support your efforts to produce the best crop possible each and every year.

Here’s to your harvest success!

Of Soils and Nutrients

Phosphate, among other things, is a catalyst, and as such it recycles. It has a function that is special, for it guides all elements into the plant except nitrogen. In other words, all elements go into the plant in phosphate form except nitrogen. Somewhere along the line there has to be a union of the phosphate atom with necessary nutrient elements for healthy plant growth. If there is a phosphate insufficiency, the plant can still uptake nutrients, but they will not be incorporated into the cell. The consequence is shrinkage. When the crop is hay, shrinkage can make the crop almost vanish. A third of the corn crop can disappear because of shrinkage. The alfalfa crop is literally annihilated when there is a phosphate shortfall. Stems will be hollow, and the difference between half a yield and a full yield.

The last cutting on a farm I worked with had 80% solid stemmed alfalfa when we foliar fed after each harvest. The yield was greatest on the fourth cutting even though it wasn't taller – but there was no shrink.

A thinner stem may permit a larger population, but if the soil has insufficient nutrients there will not be enough energy to support the plants. If corn is healthy, tubules will be packed together all the way to the center. The center or pith of the stalk should be pearly white, not the dirty gray called gummosis.

Excess nitrogen will reveal a black layer node when the stalk is cut and put under a microscope. Such tubules often are completely blocked, much like a water pipe that is completely clogged. This is always an indication that there is not enough phosphate and calcium in relation to nitrogen.

Peppermint and spearmint do not have hollow stems if correct mineralization has been part of the fertility program. Even oats have solid stems if phosphate levels are maintained correctly to permit cell nourishment and growth. Properly nourished and nurtured, such oat stems will be more like a sturdy willow than a fragile soda fountain straw.

The research station at Bethesda, Maryland fed phosphate through the leaf in order to measure the effect on rootlets. Workers found that phosphate will travel to the roots at the rate of three feet per second. When it reaches the rootlet it forms an organic acid and solubilizes fertility elements for plant uptake. But once phosphate reaches a basic level in the soil, its need is greatly reduced. 

Nitrogen can carry all essential nutrients into the plant, potassium included. That is why much of agriculture grows crops with a combination of nitrogen, potassium and lots of water. This approach paints the field deep green, but at harvest the shrink is fantastic. It reminds one of grocery store hamburger made to look superb by blending the meat with crushed ice. That same hamburger melts away in a hot skillet. 

The same thing applies to livestock. It is possible to simulate growth and weight by feeding more nitrogen and potassium and keeping the phosphate level down. The gain is simply water in the cells. In a skillet or roaster, such meat shrinks and at the table it tastes like cardboard because minerals and nutrients for really good quality meat simply weren't there. 

The environment around you will tell most of the story if you see what you look at. If you go through an area where all the trees have branches bushed out at the top but there are no branches down the tree, that is an indication of a phosphate deficiency or a lack of availability to the plant. If a tree is branched out all the way to the ground, that indicates a good phosphate level in the area, or perhaps that there was one… 

Photo credit: AgFax

…carbon in the molecular structure of the seed brings water into the soil…one part carbon will hold four parts water. There are two million pounds of soil in the top six inches of an acre. A 1% organic matter soil will thus contain 20,000 pounds of carbon, and 20,000 pounds of carbon will absorb 80,000 pounds of water – or 10,000 gallons. It takes 28,000 gallons of water to cover an acre one inch deep. The problem of a three inch rain on a 1% organic matter soil is at once apparent. Even a 5% organic matter soil – which is difficult to achieve under row crop conditions – would have only 100,000 pounds of carbon, and therefore a potential for holding 400,000 pounds of water, approximately 50,000 gallons, only enough capacity to absorb a two inch rain. Once a saturation point is reached, the rest of the water will run off. The soil management problem is further complicated by hardpan, which prevents water from moving down into a water dome or aquifer and forces it to run off. 

With good biologically active carbon in the soil, there will still be a complement of soil air…Carbon attracts moisture from the air, especially at night. If there is high humidity in the air and enough carbon in the soil, plants can get enough moisture from the air to fix a crop if there is at least 20 to 25% humidity. 

Southern California was essentially desert in the early 1900s. The hills had no grass or trees. The Soil Conservation Service presided over the seeding of mountain areas with a variety of grasses. When the water wash ran off in the spring, a green layer developed and worked its way into the valley. Now when they get rain in that area, there is a basic climate change. In fact, it is possible to so manage carbon that is will change the climate of an area. It is also possible to so mismanage carbon that droughts are created. In Iowa - where they plow every possible acre from border to border – they have created droughts in areas where this phenomenon has never been heard of before. 

It is difficult to get carbon in the soil to go down. Magnetism must first be created, meaning phosphate molecules must be utilized to create a condition supportive of bacteria. This means aeration – and incorporation of carbon dioxide into the soil. When air can no longer enter soil, carbon goes out as CO₂ gas. Bacteria that run into salt-rich plow pan areas die off, much as if they were cast into a salt brine tank. 

The chemical symbol "C" means pure elemental carbon, a product that is difficult to achieve. We use the term carbon, but this expression requires a modifier. Carbon does not go in the soil as pure carbon. Generally speaking carbon is bonded with water and nitrogen to form organic acids in the soil which contain carbon. To really make soil magnetic, carbons have to be in residence to provide food for bacteria in the form of sugars. 

A cornstalk has cellulose, a form of carbon. If you break it down, the breakdown products will include sugars. Bacteria can work on this cornstalk if they have a suitable environment. A mandatory component of that environment is oxygen. Another is moisture.

It is not uncommon to see cornbelt farmers put in soybeans after one corn season, then return the third year to plow up corn stalks that have been neatly embalmed. Dead soils form formaldehyde, the same stuff that's used to preserve cadavers until after the funeral. Formaldehydes are an anaerobic breakdown product. In some cases aerobes work from the top down and dilute and break out the preserved biomass. But aerobes cannot survive in formaldehyde. The remedy, again, is carbon.

Carbon, we have noted, keeps the soil from blowing, not because it is some foo-foo dust, but because it serves up amino acids and nitrogen – the key to stickiness, in that order, and in that order of importance. This is the soil's method of storing nitrogen from one year to the next. The conventional wisdom has farmers using a modified hydroponic system. In this view soil has little function except to prop up the crop, and maintenance of a microsystem is a luxury too costly to justify. Such a soil on injectable nitrogen is much like a drug addict. It becomes dependent on the needle arrangement. 

No-till is to a large extent needle-till, forever dependent on hard chemistry. There is also a negative aspect to no-till, an inability to get the carbon to go down without air. No-till works best if the crop residue is incorporated into at least the top two inches of soil – a sort of contradiction. There has to be soil contact for microbial breakdown. There is usually as much biomass under as above the soil. 

Minimum tillage, in the beginning, is better than most management systems in keeping topsoil from blowing. With residue incorporated in the top inch or two of soil, it permits enough contact for meaningful activity. Basically, organic matter is some form of plant or animal life. Mixed with the life and work of microorganisms, organic matter delivers a most valuable constituent, carbon. Carbon can also come into an active soil through the air via the agency of bacteria. 

Another source is photosynthesis. The leaf takes in CO2 from the atmosphere through its stomata. Organic matter in the soil decomposes under proper conditions, releasing carbon dioxide for plant use. Decomposing bacteria break down into humus – a point at which parent material can no longer be recognized – organic material such as corn stover. The efficiency of this process is governed by the ratio of carbon to nitrogen in the soil, which at its optimum level should be twelve parts of carbon to one part of nitrogen. 

…bottom line seems to be that poor soils with less than 1% organic matter are not uncommon. Midwest prairie soils were running 10 to 12% in organic matter before the arrival of the moldboard plow. Today most of them have organic matter in the 2 to 3% range. Only a few well managed soils have a 5 to 6% index. Only rarely will 8% become an entry on a soil audit. Once intensified farming is started, most excellent soils have a tendency to back down to 5 or 6%.

…When such soils have a high carbon content, the roots will travel through the soil rapidly.

 

- Excepted from Mainline Farming for Century 21 - Dr. Dan Skow and Charles Walters