EFFECTS OF SUPPRESSION OF HERBICIDES ON VINEYARD NITROGEN STATUS, AND SOIL MICROBIAL AND CHEMICAL INDICATORS

eve.durocher@educagri.fr

Background

• Cover cropping in vineyards can bring many ecosystem services but can induce competition for nitrogen and water with grapevine (Celette et al., 2009).

• Cover cropping is widespread in Northern Eastern of France but chemical weeding under vine rows is still widely used to limit competition (Wilmes, 2014).

• Grapevine nitrogen nutrition, depends on N availability in soil and microbial activity, which can be affected by cultural practices (Steenwerth and Belina, 2008).

• Since 2014, the project « soil management in viticulture » aims to study the impact of suppression of herbicides on nitrogen dynamics in grapevine and in soil.

Experimental design

Financial partners

ResultsNitrogen Balance Index (NBI) of grapevine

Conclusion and perspectives

Technical partners

DUROCHER E.1, LANGENFELD, A.2, LEY L3., KLEIN C.1, THIOLLET-SCHOLTUS M.4, NASSR, N.2

1 EPLEFPA les Sillons de Haute Alsace, France ; 2 RITTMO Agroenvironnement, France ; 3 INRA SEAV, France ; 4 INRA UR-0055 ASTER, France

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Experimental plot

March April May June July August Sept Oct Nov

Budbreak Veraison Leaf-fall

- Bacterial/fungal biomass (16S & 18S rDNA)- Metabolic diversity (Biolog ®) : Average Well Color Development

(AWCD) + Functional Richness (FR)- N mineralization + N mineral concentration (NO3

-, NH4+)

Tillage Cover cropping

Chemical weeding

Cover croppingTillage

Classical system (CS) : chemical weeding under row

Innovative system (IS) : cover cropping + tillage under row

YieldWood weight

Nitrogen Balance Index - NBI (Chlorophyll

fluorescence of leaves)

Yeast Available Nitrogen in

must

Grapevine :nitrogen indices

Soil : microbial and chemical indices0-30 cm under rows

Site : Domaine de l’EcoleRouffach city

Grape variety : RieslingSurface : 0.30 haSoil : silty clayey

calcareousPlantation : 1998

Measurements (2014-2016)

2014

2016

NBI values

Classical

Innovative

Classical

Grapevine Nitrogen yield and Nitrogen indices

Low nitrogen status

• 2014 and 2015 (not shown) : Nitrogen deficiency in IS

effect of competition with cover crop at veraison

• 2016 : N deficiency less pronounced in IS

Effect of fertilization applied in May 2016

• N deficiency in center of CS lack of fertilization

Microbial and chemical indices

Fig. 4 : Principal Component Analysis of microbial and chemical indices

3 stages

• 2014: drop of Nitrogen indices of IS (NBI, Wood weight and Yeast available nitrogen)

• 2015 : stronger drop of yield and Nitrogen indices IS grapevine is more impacted the 2nd year

Decision : addition of an organic fertilization in 2016• 2016 : recover of N indices following organic fertilization but

yield still low• Presence of weed induces a competition for nitrogen

References : Celette F., Findeling A., Gary C., 2009. Competition for nitrogen in an unfertilized intercropping system: The case of an association of grapevine and grass cover in a Mediterranean climate. European Journal of Agronomy, 30, 41-51.Steenwerth K., Belina K.M., 2008. Cover crops and cultivation: Impacts on soil N dynamics and microbiological function in a Mediterranean vineyard agroecosystem. Applied Soil Ecology, 40, 370-380. Wilmes C., 2014. Un désherbage mécanique sur vigne qui progresse au delà des producteurs bio. Agreste, SRISE Alsace.

Fig.2 : Yield and nitrogen status indices of grapevine of innovative system, as a percentage of classical system from 2014 to 2016.

Fig 1 : Nitrogen Balance Index maps of Classical and Innovative Systems in 2014 and 2016

Innovative

• Transition towards non chemical soil management can induce significant drop of grapevine’s yield and others indices due to an competition for nitrogen, but organic fertilization can counteract these effects.

• However, at the soil microbial level, year effect is more noticeable than soil cover cropping under row.• At this stage, further analyses in next years are needed in order to determine which parameter is more sensitive to soil management

practices.

Effects of innovative soil management : - At grapevine level : induces N drop visible in leaves,

grapes and wood, with a yield decrease.Fertilization enhances N availability but effect on yield is

delayed.- At soil level : no significant effects on microbial

parameters and on N availability in soil.

Acknowledgements : the Authors would like to thank the Domaine de l’Ecole, Agence de l’Eau Rhin-Meuse and ComitéInterprofessionnel des Vins d’Alsace

• N mineralization rate and other microbial indices taken separately don’t show significant differences

between the 2 systems• PCA : Year effect stronger than

system effect • NO3

- concentration correlates with 16S and 18S DNA

Microbial communities more sensitive to climatic conditions than

soil management practices

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0 50 100 150

N m

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Days of incubation at 28°C

ClassicalInnovative

0 50 100 150Days of incubation at 28°C

0 50 100 150Days of incubation at 28°C

Fig. 3 : Nitrogen mineralization rates in soil at budburst

201620152014

High nitrogen status

0%

50%

100%

Yield (t.ha-1)

Yeast Availablenitrogen (mg.l-1)

Wood weight(kg.vine-1)

Nitrogen BalanceIndex (NBI_R)

Classical system

Innovative system 2014

Innovative system 2015

Innovative system 2016