Nutrition Management
This page describes how we manage vine nutrition in six sections:
Irrigation System Management deals with annual maintenance and ongoing adoption of new technologies
Irrigation describes when we irrigate and how
Nutrition Requirements deals with measuring the available nutrients in the ground and the vines.
Soil Amendment deals with dispersing nutrients to the soil
Foliar Sprays describes how we spray nutrients directly on the plant leaves
Data Management explains what we record and report on
The following link leads to an excellent general presentation on grapevine nutrition: http://www.uvm.edu/~fruit/grapes/gr_horticulture/GrapevineNutrition.pdf. Our current approach to nutrition management is still very amateur. We irrigate when the plants look stressed. We send soil and plant samples to third-party laboratories to test nutrition deficiencies, but we are not yet confident how to interpret the results and take corrective action. We amend the soil with fertilizers, and we spray nutrients onto the leaves based on recommendations from consultants and experienced vineyard managers.
Irrigation System Management
Irrigation systems are complex and fragile. They require a fair amount of upkeep because of earth movements and erosion, interference from animals, general wear and tear, and evolving technologies. There is a never-ending effort to use less water and be more efficient. In our region, the bulk of necessary water comes from winter rain stored in the clay soils. Our long-term goal is to supply each vine with the estimated amount of water it needs without wasting any in evaporation from the vineyard floor or underground drainage. As each plant sits in slightly different soils, has different exposure to sun and wind, and varies in size and maturity – the ideal solution is to measure each plant’s requirement in near real-time and regulate the supply accordingly. This is not yet economically feasible but should be achieved within the next ten years at an investment of less than $10 per vine. In the meantime, we estimate the demand and regulate the supply manually by vineyard block.
Irrigation
As a general rule, mature vineyards need little irrigation. The vines’ root system should reach deep enough to get to the required moisture. Excess irrigation of mature vineyards prevents the roots from growing deep and makes the grapes watery. Young vines need irrigation for the first three years after planting because they only have shallow roots – that is the principal reason for the drip irrigation system built into the trellis.
There are four exceptions to the rule:
We irrigate the vineyard thoroughly once right after harvest when the summer heat has stressed the vines and now need to start focusing on growing the roots
We irrigate the vineyard a few days before extreme heat waves when we expect temperatures to exceed 95 F for more than a day. This assumes we get good weather forecasts and can supply the plant ahead of time with extra water reserve.
We irrigate the vineyard in the final days of berry maturation when we detect an imbalance between sugar levels and phenolic maturity of the grapes. In hot years, the sugars accumulate faster, and the maturity of the skins and seeds may lag. In this instance, intermittent irrigation during the last weeks before picking allows grapes to mature fully, prevents premature shriveling, and keeps the sugar levels in check.
We irrigate new replacement vines for the first three years every 1-2 weeks. This has to be done plant by plant. We used to use 5-gallon buckets, with a 1/16th-inch hole at the bottom, so they release water only very slowly. The buckets were placed next to each young vine and manually filled by a hose. The picture shows the setup. Since it is time-consuming to refill the buckets by hose every week, we added a second irrigation line controlled only to water the new plants. That line is on a timer for automatic irrigation.
Identifying Nutrition Requirements
There are three basic approaches to understanding whether plants need nutrition supplements:
Visual inspection: looking for visual clues signalling nutritional deficiencies or excesses.
Soil Testing: measuring the availability of nutrients in the soil
Petiole testing: measuring the nutrients taken up from the soil and stored in the plant
Experienced farmers and vineyard managers can look at a plant and identify nutritional deficiencies. Typical clues are the abnormal colouration of leaves or stunted growth.
Every 3 years or so, we test the soils for their nutrient and trace metals .We take about a dozen soil samples 3 to 12 inches from the surface in each block and mail them to a testing laboratory. Testing laboratories provide good instructions on how to take the samples and how to send them in. A week later we get the results by email. Following is a typical soil test report.
Testing soils is easy, interpreting the results and taking appropriate action is far more difficult. Each soil type has vastly different characteristics for water and chemical extraction. The challenge is to understand how the plant’s roots interact with which types of soil under different humidity and temperature conditions. Furthermore, the soil characteristics can vary greatly even over short distances. To complicate things even further, fertilizers take the better part of a season to sink into the ground and distribute, and the plants take another year or two to extract and react fully.
We have used an excellent consultant (http://www.growyoursoil.org) to interpret soil tests prior to planting when we added significant amounts of soil amendments to pastures (see Soil Analysis & Amendments on the Site Preparation page).
The difficulties in interpreting soil analysis results and correcting with fertilizers have led to an alternative approach: analyse the plant tissues instead. We collect around 50 petioles (stems of leaves) from plants in each block and mail them to a testing laboratory. Following is a sample of a resulting plant analysis report.
We then correct the shortages of nutrients in the tissue by spraying chemicals directly onto the leaves — not a very natural remedy, but quicker and more effective. For the primary nutrients (Nitrogen, Phosphorus, and Potassium), foliar sprays are only a band-aid; for micronutrients (iron, zinc, boron, manganese), they are the preferred application method.
Soil Amendments & Fertilizers
The primary nutrients (N, P, and K) can be sourced from inorganic (usually mined) or organic materials (collected on farms). Inorganic materials such as gypsum (Calcium Sulfate) or lime (Calcium Oxide) release nutrients faster than organic materials such as compost or manure. So, the challenge is to understand how much of which component needs to be added and how long it takes the plants to absorb it before it is washed away, evaporates, or disappears otherwise. Note that the excessive addition of nitrogen ends up in the groundwater and is a significant source of pollution (see https://www.cdfa.ca.gov/Is/ffldrs/frep/pdfs/GrapeBrochureWeb.pdf for a good summary on nitrogen application in vineyards). Another good source of general information is the International Plant Nutrition Institute (http://www.ipni.net/ ). The best summaries of fertilizers and soil amendments I have come across are from the University of Maryland https://extension.umd.edu//sites/extension.umd.edu/files/_images/programs/hgic/Publications/HG42_Soil_Amendments_and_Fertilizers.pdf and the Colorado State University: http://extension.colostate.edu/topic-areas/yard-garden/choosing-a-soil-amendment/.
We don’t yet have a solid program for applying fertilizers and soil amendments. Instead, we rely on recommendations from consultants following soil tests or from experienced vineyard managers on an ad-hoc basis. Following is a list of what we have used in the past:
YaraVera Urea (46-0-0)
Mini-prilled Calcium Sulfate from Art Wilson
Mono-Ammonium Sulfate from Simplot (11-52-0)
Greenbelt Fertilizer from Romeo (25-14-14)
Potassium Sulfate from Yara (0-0-50)
Rapid release limestone from ArtWilson
Maximo 360 Zinc Sulfate
Ferreous Sulfate from EcoFusion
SuperIron 11% from Simplot
Sodium Borate / Solubor from U.S. Borax
Manganese from PrinceMinerals
Bonemeal from Kellog Garden
Mushroom compost from a nearby mushroom farm
Horse manure from a nearby farm
Hydroprill 20-20-20. On the day after harvest, we put one spoonful of Hydropril under each dripper and irrigate for 4 hours (recommendation by Rick Berg)
There is much room for improvement.
Foliar Sprays
With foliar sprays, we apply nutrients directly to the leaves. Most of the time, we combine foliar sprays with Pesticide Sprays (see next page). We currently use:
Eleanor’s VF-11 (Nitrogen 0.15%, Phosphate 0.85%, Soluble Potash 0.55%): general plant food for foliar feeding.
LIG-Calcium+B: Calcium Lignosulfonate: Foliar Nutrient to add Calcium & Boron. to promote flowering and even fruit set; increases fungal resistance.
LIG-Trace: Complexed Lignosulfate: Foliar Nutrient to add trace elements to sulfate-based sprays
CropBiolife-O: Foliar Spray containing naturally occurring flavonoids that stimulate the biosynthetic pathways
Data Management
There are four data management tables and related layouts covering nutrition management
NutrientTest is used to record results from soil tests and foliar tests as well as recommendations for soil enhancement based on the test results
SoilAmendments contains the descriptions of soil amendments that are currently in inventory and used
FoliarNutrients contains the descriptions of foliar sprays currently in inventory and used
The “INPUT: VineyardActions “-Layout is used to record nutrition management tasks
We use the “ALL: NutrientTests”-Layout to input results from foliar tests. The screenshots show the results from a foliar test on Nov 10, 2014, in the Me2 block
We use the “ALL: VineyardActions”- layout to record the addition of a soil amendment. This screenshot shows the addition of 1,400 lbs of mushroom compost to the LFLR block in April 2018
