NITROGEN MANAGEMENT IN WINE GRAPE VINEYARDS

progressive viticulture NITROGEN MANAGEMENT IN WINE GRAPE VINEYARDS Stan Grant Progressive Viticulture & Mid Valley Agricultural Services NITROGEN IS A TIMELY TOPIC Wineries are concerned about fruit nitrogen The state water resources control board have focused their attention on nitrogen Sustainable wine growing certifications include nitrogen management standards Progressive Vi culture 2016 1

NITROGEN IS A TIMELY TOPIC Our knowledge & resources for managing nitrogen have increased Our appreciation for the pivotal role of fertilizer nitrogen in balanced mineral nutrient management has deepened N uptake greatly influences the uptake of other nutrients, which accompany it N uptake & assimilation depends on adequate levels of certain micronutrients OUR OUTLINE Vineyard nitrogen (N) facts Vineyard nitrogen monitoring Forms of applied nitrogen the N tool set Nitrogen application rates & timings Optimizing vineyard nitrogen efficiency Fruit nitrogen VINEYARD NITROGEN FACTS Progressive Vi culture 2016 2

VINE NITROGEN FACTS Grapevines require more N than any other mineral nutrient N is a grapevine growth factor N availability is equally as important as water availability for growth & development Grapevine N imbalances are detrimental in the current year & sometimes, beyond VINE NITROGEN IMBALANCES Too Little Restricted shoot growth Pale foliage Reduced fruit yields Impaired grape ripening Slow fermentations Increased winterkill Decreased capacity Vine decline Too Much Excessive shoot growth Dark foliage Reduced fruit yields Impaired grape quality Fast fermentations Decreased tissue integrity Decreased fruitfulness Poor anchorage/attachment NITROGEN SUPPLY FACTS The atmosphere is the ultimate source of N Certain soil microbes fix atmospheric N Vine foliage may take up small quantities of N from rainfall Very little atmospheric N contributes directly to vineyard N Vineyard N must be supplemented with atmospheric N fixed by other means Progressive Vi culture 2016 3

SOIL NITROGEN FACTS Vine roots take up mineral N forms (NO 3-, NH + 4 ) There are no native forms of mineral N in soils. (i.e. they are not present in rocks) Most residual N in soils occur in organic forms contained within soil organic matter (OM) Since most California soils are low in OM, they are also normally low in residual N SOIL NITROGEN FACTS Mineral-N availability depends on soil microbes to: Decompose OM & release organic-n Transform organic-n into mineral-n The supply of mineral N is transient & normally low being either Consumed by plants or soil microbes or Lost from the root zone LEACHING LOSS Source: Provin & Hossner. Undated. Progressive Vi culture 2016 4

Erosion, Gases Harvested Fruit Above Ground Below Ground Leaching Inefficiencies Cover Crop Tissues Soil Microbes Soil Organic Matter Woody Tissues Nutrient Demand OUR NITROGEN MANAGEMENT GOAL Strive for maximum N efficiency Enhance the natural processes & other root zone factors affecting N availability & use by grapevines Optimize the value of applied inputs through careful selection of N form, rate, timing, & placement, & adequate levels of other mineral nutrients MONITORING VINEYARD NITROGEN Progressive Vi culture 2016 5

VINEYARD NITROGEN MONITORING SOIL SUPPLY Soil N is commonly analyzed as nitrate-n (NO 3 -N), which is highly transient in soils NO 3 -N 1 ppm may indicate a shortage NO 3 -N > 25 ppm likely indicates excess Some labs analyze potential release from soil OM Soil analysis challenge = providing an accurate representation of the N supply in the vineyard root zone over time VINEYARD NITROGEN MONITORING VINE STATUS Vine tissue N is commonly analyzed as petiole nitrate-n Transport N form (yet to be assimilated) May accumulate due to high soil moisture, cloudiness, & lack of micronutrient cofactors required for assimilation False sufficiency: slow release from storage w/in cells & redistribution between tissues Bloom NO 3 -N < 100 to 200 ppm is low Bloom NO3-N > 3000 ppm may be high VINEYARD NITROGEN MONITORING VINE STATUS Also analyzed as total N = N in organic molecules (i.e. assimilated N) Bloom petiole total N < 0.8% is low Bloom petiole total N > 2.5% is high Use both petiole nitrate-n & total N along with visual vineyard observations Progressive Vi culture 2016 6

VINEYARD NITROGEN MONITORING VISUAL CUES Low N Indicators Slow shoot growth Short internodes Small leaves Short shoots Insufficient canopy Pale foliage High N Indicators Rapid shoot growth Long internodes Large leaves Long shoots Excessive canopy Dark foliage Progressive Vi culture 2016 7

TAKE HOME MESSAGE: Effective vineyard nitrogen monitoring requires a combination of methods! Visual observations + tissue analysis results FORMS OF APPLIED NITROGEN THE VINEYARD NITROGEN TOOL SET Progressive Vi culture 2016 8

FORMS OF APPLIED NITROGEN Nitrate (NO 3 - ): highly soluble, highly mobile, & transient in soils; taken up directly by roots; enhances nutrient cation uptake (K, Mg, Ca); & fast acting in vines Common fertilizer forms: Dry & liquid calcium nitrate Foliar potassium nitrate Mined sodium nitrate (organic) Some irrigation waters are nitrate sources FORMS OF APPLIED NITROGEN Ammonium (NH 4 + ): interacts with soil matrix, most is converted to NO 3 before uptake, depresses cation uptake while enhancing anion uptake (P, S, Cl), & transient in vines Common fertilizer forms: Ammonium sulfate (21-0-0-24(S)) dry Ammonium thiosulfate (12-0-0-26(S)) liquid Monoammonium phosphate (11-52-0) dry Ammonium polyphosphate (10-34-0) liquid FORMS OF APPLIED NITROGEN Urea (CO(NH 2 ) 2 -N): most is converted to NH 4 & then NO 3 before uptake by roots Dry urea (46-0-0) Foliar low biuret urea Fertilizers with combinations of N forms CAN-27 (dry) CAN-17 (liquid) UAN-32 (liquid) UCAN-22 (liquid) Progressive Vi culture 2016 9

FORMS OF APPLIED NITROGEN Grapevines benefit from a mixture of nitrate & ammonium applied either in sequence or together Minimizes root pathogens associated with excesses of one or the other N form Promotes neutral soil ph Provides greatest growth benefit Improves balance of other mineral nutrients FORMS OF APPLIED NITROGEN N Form Nitrate Ammonium Urea Organic Amendments Effect on Soil ph Increase (alkalizing) Decrease (acidifying) Decrease (acidifying) Neutral (weakly acidifying) FORMS OF APPLIED NITROGEN Organic Amendments Manure Pomace Composted organic materials Leguminous cover crop residues Organic N fertilizers: fish emulsion, fish meal, blood meal, bone meal, & hoof & horn meal Progressive Vi culture 2016 10

FORMS OF APPLIED NITROGEN Mineral fertilizers Nitrate-N (NO 3 -N) Ammonium-N (NH 4 -N) Urea-N (CO(NH 2 ) 2 -N) Organic amendments & fertilizers Manure-N (High C/N) Compost-N (Low C/N) N in other organics Dry: 11% to 46% Liquid: 1% to 32% 0.5% to 4.5% 1% to 2% 1% to 13% MANURE-NITROGEN Parameter Unit Quantity Moisture Content % 37 Bulk Density lb / yd3 548 Total N Concentration % dry wt 2.7 % fresh wt 1.7 lb / yd3 9.3 lb / ton 34 Application Rate yd / acre 9 N Applied lb / acre 84 MANURE-NITROGEN Parameter Quantity Handling Nutrient Loss 10% Mineralization Rate Year 1 45% Year 2 20% Year 3 10% Denitrification Coefficient 0.85 Fertilization Efficiency 65% Efficiency Index Year 1 0.22 Year 2 0.10 Year 3 0.05 Progressive Vi culture 2016 11

MANURE-NITROGEN FORMS OF APPLIED NITROGEN Which is better: organic amendment-n or inorganic fertilizer-n? Fertilizer-N allows precision N applications To accommodate root zone conditions Synchronize with uptake & vine N demand Amendment-N builds resilience through consistency in the soil N supply Which is better? Neither. TAKE HOME MESSAGE: Apply a combination of N forms to maximize benefits & to minimize undesirable side effects! Progressive Vi culture 2016 12

NITROGEN APPLICATION RATES AND TIMINGS HOW & WHEN TO USE THE N TOOL SET NITROGEN APPLICATION RATES Seasonal N application rates usually depend on N removal = crop N demand ( 3 lb/ton) N in harvested fruit came mainly from reserves in woody tissues & the soil = replenishment N demand Include an inefficiency factor to account for events between N entry into soil & uptake NITROGEN APPLICATION TIMINGS Allocate applied N over time in proportion to vine size, crop load, & stage of development Early season - rely on stored N reserves in woody tissues & residual N in the soil Progressive Vi culture 2016 13

180 160 140 120 100 80 60 40 20 0 5/23/17 200 180 PERCENT INCREASE IN GRAPEVINE NITROGEN CONTENT Sources: Conradie (1980) & Conradie (1981) Cell Multiplication Maturation Senescence Dormancy Nitrogen Content Increase (%) 160 140 120 100 80 60 40 20 0 3/28/03 4/11/03 N Demand For Growth Stored 4/25/03 5/9/03 End of Bloom Residual 5/23/03 6/6/03 6/20/03 Applied 7/4/03 Veraison 7/18/03 8/1/03 Date 8/15/03 Harvest 8/29/03 9/12/03 N Demand For Storage 9/26/03 Applied 10/10/03 10/24/03 Leaf Fall 11/7/03 11/21/03 12/5/03 12/19/03 Typical wetted soil volume of 4% to 13%, depending on drip emitter density ACCOMMODATE ROOT ZONE DYNAMICS Big concern: early soil dry down, early root zone contraction, & reduced access to soil N Most common for vineyards on sandy, rocky, & shallow soils (low water holding capacity) Nutrient Content Increase (%) End of Bloom Veraison Harvest Leaf Fall 3/28/03 4/11/03 4/25/03 5/9/03 5/23/03 6/6/03 6/20/03 7/4/03 7/18/03 8/1/03 Date 8/15/03 8/29/03 9/12/03 9/26/03 10/10/03 10/24/03 11/7/03 11/21/03 12/5/03 12/19/03 Progressive Vi culture 2016 14

NITROGEN APPLICATION STRATEGY Considering all factors, it is best to split applied N into several small applications to: Best match vine N demand Optimize N uptake & fertilization efficiency Avoid excess salinity Avoid toxicity Apply with liquid OM to enhance efficiency & reduce risks within the small root zone Fertilizer Fertilizer/ Fertigation Timing Formulation Acre gal Shoot Emergence 3-12-14-4(S) 0 (Applied during 1 CN 9 0 early irrigation) MVAS Liq. OM/OA 0 Subtotal 0 Post bloom 3-12-14-4(S) 9 CN 9 3 MVAS Liq. OM/OA 8 Subtotal 20 Veraison 3-12-14-4(S) 5 CN 9 0 MVAS Liq. OM/OA 8 Subtotal 13 Ripening 3-12-14-4(S) 4 CN 9 1.5 MVAS Liq. OM/OA 8 Subtotal 13.5 Post Harvest 3-12-14-4(S) 12 CN 9 0 MVAS Liq. OM/OA 8 Subtotal 20 SEASONAL TOTAL 67 Urea Ammonium A + U Nitrate N lb/ac lb/ac lb/ac lb/ac lb/ac 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3.0 3.0 0.0 3.0 0.0 0.2 0.2 3.1 3.3 0.0 0.3 0.3 0.0 0.3 0.0 3.5 3.5 3.1 6.6 0.6 0.6 1.2 0.3 1.5 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.3 0.6 0.9 1.5 0.3 1.8 0.5 0.5 1.0 0.2 1.2 0.0 0.1 0.1 1.5 1.6 0.0 0.3 0.3 0.0 0.3 0.5 0.9 1.4 1.8 3.2 1.4 1.4 2.9 0.7 3.6 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.3 1.4 1.8 3.2 0.7 3.9 2.5 7.1 9.6 5.9 15.5 Copyright 2002 Progressive Viticulture TAKE HOME MESSAGE: Consider seasonal vine N demand & root zone conditions in the allocation of vineyard N inputs! Progressive Vi culture 2016 15

OPTIMIZING VINEYARD NITROGEN EFFICIENCY OPTIMIZING VINEYARD NITROGEN EFFICIENCY Maximize N reserves stored in woody tissues to: Ensure adequate N to support early season growth Decrease the need for early season N fertilizer, which is often difficult to apply To replenish or build reserves, apply fertilizer N after harvest any time before leaf fall OPTIMIZING VINEYARD NITROGEN EFFICIENCY Maximize soil organic matter to: Promote N cycling & availability in the soil Enhance early season vine N uptake Reduce N losses To build & maintain OM, annually apply organic amendments, such as cover crop residues While fertigating, apply liquid OM to enhance efficiency Progressive Vi culture 2016 16

OPTIMIZING VINEYARD NITROGEN EFFICIENCY Ensure adequate tissue concentrations of other nutrients involved in N metabolism Boron: required nitrate uptake by vine roots Manganese, copper, & molybdenum: nitrate assimilation in vine foliar tissues Other mineral nutrients involved carbon assimilation, such as magnesium & iron NITROGEN FORMS & INEFFICIENT SITUATIONS Nitrate Leaching with excessive irrigation Denitrification with prolonged soil saturation Ammonium Ammonia volatilization from wet soil surfaces under warm, breezy conditions Urea a high potential for ammonia volatilization losses. Also, may gas off decomposing OM. All forms surface runoff & soil erosion AVOIDING INEFFICIENCIES ASSOCIATED WITH N FORMS Assure adequate subsurface drainage prior to planting Manage soil for maximum infiltration & permeability Progressive Vi culture 2016 17

AVOIDING INEFFICIENCIES ASSOCIATED WITH N FORMS Immediately incorporate dry N fertilizer & soil amendments after application Manage to conserve topsoil AVOIDING INEFFICIENCIES ASSOCIATED WITH N FORMS Use sound irrigation & fertigation practices Use N fertigation rates & timings that are synchronized with vine N demand Irrigate sufficiently following N application to assure incorporation below the soil surface Avoid over irrigation: soil saturation & leaching USE FOLIAR FERTILIZATION TO ADVANTAGE Foliar N fertilizer applications have value in some situations Early season while soils are wet & cool, & root activity is low In combination with miticides to increase the activity of damaged leaves (potassium nitrate) Dry farmed vineyards Progressive Vi culture 2016 18

INCREASING FRUIT NITROGEN FRUIT NITROGEN Some vineyards low in N produce fruit low in yeast assimilable N (YAN < 140 ppm) YAN = alpha amino acids + ammonia Fruit low in YAN is prone to slow & stuck fermentations, & as a result, off aromas Winemakers may add N, but at a cost & with increased risk of undesirable side effects Low YAN vineyards have higher than normal post bloom N demand FRUIT NITROGEN & SOIL FERTILIZER N Fruit YAN responsiveness to soil applied N varies among varieties (Merlot > Cab. Sauv.) Varietal responses may be related to amino acid composition (assimilable vs. non-assimilable) Fruit YAN appears more responsive to soil applied nitrate than to ammonium Fruit YAN ceases to respond to soil applied N very early in the ripening period Progressive Vi culture 2016 19

FRUIT NITROGEN & FOLIAR FERTILIZER N Foliar applied low biuret urea will increase fruit YAN Requires multiple applications (pre-bloom, BBsize berry, bunch closure) Works best with cofactors (Mn, Cu, B, & Mo) Fruit YAN responsiveness to foliar applied N varies among varieties (Cab. Sauv. > Merlot) Fruit YAN increases with increasing foliar N application rate 200 Merlot Yeast Assimilable Nitrogen at Harvest as a Function of Rate of Low Biuret Urea Applied to the Foliage Post Bloom 180 y = 1.938x + 120.78 R² = 0.99359 Yeast Assimilable Nitrogen (ppm) 160 140 120 100 80 60 40 Minimum Acceptable YAN Concentration 20 0 0 10 20 30 Low Biuret Urea Application Rate (lb/acre) GRAPE YAN MANAGEMENT Start the season with adequate N in balance with other mineral nutrients to minimize YAN problems To increase fruit YAN, apply N fertilizer between early fruit set through early ripening A combination soil & foliar applied fertilizers may be most effective for increasing YAN Progressive Vi culture 2016 20

GRAPE YAN MANAGEMENT Use a balance nutrition approach with soil applied N Apply a high rate of CN-9 for rapid movement to the shoot Ensure adequate K, S, Fe, Mn, Cu, B, Mo & perhaps others (e.g. P, Mg) Avoid ammonium & chloride during this time Fertilizer Fertilizer/ Fertigation Timing Formulation Acre gal Shoot Emergence 3-12-14-4(S) 12 (Applied during 1 CN 9 2 early irrigation) MVAS Liq. OM/OA 8 Subtotal 22 Post bloom 3-12-14-4(S) 12 CN 9 5 MVAS Liq. OM/OA 8 Subtotal 25 Veraison 3-12-14-4(S) 5 CN 9 0 MVAS Liq. OM/OA 8 Subtotal 13 Ripening 3-12-14-4(S) 4 CN 9 2 MVAS Liq. OM/OA 8 Subtotal 14 Post Harvest 3-12-14-4(S) 12 CN 9 0 MVAS Liq. OM/OA 8 Subtotal 20 SEASONAL TOTAL 94 Urea Ammonium A + U Nitrate N lb/ac lb/ac lb/ac lb/ac lb/ac 0.0 4.0 4.0 0.0 4.0 0.0 0.1 0.1 2.0 2.2 0.0 0.3 0.3 0.0 0.3 0.0 4.4 4.4 2.0 6.5 0.0 4.0 4.0 0.0 4.0 0.0 0.4 0.4 5.1 5.5 0.0 0.3 0.3 0.0 0.3 0.0 4.6 4.6 5.1 9.7 0.6 0.6 1.2 0.3 1.5 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.3 0.6 0.9 1.5 0.3 1.8 0.5 0.5 1.0 0.2 1.2 0.0 0.1 0.1 2.0 2.2 0.0 0.3 0.3 0.0 0.3 0.5 0.9 1.4 2.3 3.7 1.4 1.4 2.9 0.7 3.6 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.3 1.4 1.8 3.2 0.7 3.9 2.5 12.7 15.2 10.4 25.6 Copyright 2002 Progressive Viticulture GRAPE YAN MANAGEMENT Increasing YAN with foliar urea applications At least 3 applications between fruit set & early ripening at > 10 lb/acre are required Apply nitrate assimilation cofactors to assure maximum use of N taken up from the soil, including Fe, Mn, Cu, B, Mo Progressive Vi culture 2016 21

CONCLUSIONS CONCLUSIONS Careful vineyard N management saves $ s; optimizes vine growth, yield, & fruit quality; & avoids environmental problems Attentive vineyard monitoring facilitates effective N management Carefully select a combination of N sources, rates, timings, & application techniques to meet vine N demand & optimize vineyard N use THANK YOU Progressive Vi culture 2016 22

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