# Enzymatic activities in crop and grassland soils and the impact of copper addition

Isabelle Trinsoutrot-Gattin, Marthe Vinceslas-Akpa, Caroline Bailleul, Christian Mougin, Karine Laval

► To cite this version:

Isabelle Trinsoutrot-Gattin, Marthe Vinceslas-Akpa, Caroline Bailleul, Christian Mougin, Karine Laval. Enzymatic activities in crop and grassland soils and the impact of copper addition. Third International Conference on Enzymes in the Environment, Jul 2007, Viterbo, Italy. 2007. hal-01601168

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Submitted on 3 Jun 2020

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# Enzymatic activities in crop and grassland soils - Impact of copper addition

**Isabelle Trinsoutrot-Gattin, Marthe Vinceslas-Akpa, Caroline Bailleul, Agathe Brault, Christian Mougin and Karine Laval**
# Introduction

* Soil : non-renewable resource essential for life

* Several functions :

* Physical and cultural environment for humankind

* Food and biomass production

* Storing, filtering and transformation of organic matter

* Habitat and gene pool of living organisms...

* Pressures : agricultural production, urban and industrial development, transport networks, leisure activities...

* Necessity to guaranty the protection and sustainable use of the soil

<figure><img src="image_2.png" /></figure>

→ Project of European policy 2006.
* Current tools in agronomic practices : physical and chemical properties

* Soil organisms responsible for biogeochemical cycles, ...

* This study is a part of a vast project intending to elaborate an index of the biological state of soil.

<figure><img src="image_3.png" /></figure>

microbial, fungal and bacterial biomass

<figure><img src="image_4.png" /></figure>

**Enzymatic activities**

* Enzymatic activities :

* Soil functioning

* Scientifically recognized

* Integrative tool : pedological characteristics, climate, soil management
Objectives

✓ Impact of copper on soil enzymatic activites

✓ Considering the natural variations of the enzymatic activities in our referenced agricultural systems (grassland and crop plots)
Material and Methods
Enzymatic activities assessed

<table><thead><tr><td>Enzymes</td><td>Substrate</td><td>pH</td></tr></thead><tbody><tr><td>Dehydrogenase</td><td>1,3,5-triphenyltetrazolium chloride (TTC)</td><td>7</td></tr><tr><td>Acid Phosphatase</td><td>p-nitrophenyl phosphate (PNP)</td><td>6,5</td></tr><tr><td>Alkaline Phosphatase</td><td>p-nitrophenyl phosphate (PNP)</td><td>11</td></tr><tr><td>β-glucosidase</td><td>p-nitrophenyl b-glucoside (PNP)</td><td>6</td></tr><tr><td>N-acetyl glucosaminidase</td><td>p-nitrophenyl acetyl glucosaminide (PNP)</td><td>6</td></tr><tr><td>Urease</td><td>urea</td><td>7</td></tr></tbody></table>
# Material and Methods - Field plots

Two sites, located in the North West of France

20 samples per plot

<figure><img src="image_5.png" /></figure>

<figure><img src="image_6.png" /></figure>

Yvetot

18.2% clay
62.1% silt
19.7% sand

Crop pH 6,8

<figure><img src="image_7.png" /></figure>

Meadow pH 6,5

<figure><img src="image_8.png" /></figure>

Meadow pH 5,8

<figure><img src="image_9.png" /></figure>

Saint Georges sur
Fontaine

18.0% clay
67.2% silt
14.8% sand

April, June, October
Material and Methods
Cosme experimentation

<figure><img src="image_10.png" /></figure>

Undisturbed cosmes sampled from
Yvetot grassland and crop plots.

5 cosmes for each model
4 dates: 0, 7, 35 and 70 days

Incubation in field conditions

Models : Control
2 ppm Cu
200 ppm Cu

<figure><img src="image_11.png" /></figure>

<figure><img src="image_12.png" /></figure>
## Temporal and spatial variations for enzymatic activities

Acidic, alkaline phosphatases and b-glucosidase activities exhibit a great variability

The level of activities is higher in grassland than in crop plots

<figure><img src="image_13.png" /></figure>

Yvetot site

<figure><img src="image_14.png" /></figure>
# Enzymatic activities in Yvetot plots and in cosmes

<figure><img src="image_15.png" /></figure>

Enzymatic activities are similar in plots and control cosmes

<figure><img src="image_16.png" /></figure>

Validation of our undisturbed cosmes approach
# Impact of the two copper concentrations on enzymatic activities in crop cosmes

<figure><img src="image_17.png" /><figcaption>b-glucosidase - crop</figcaption></figure>

<figure><img src="image_18.png" /><figcaption>dehydrogenase - crop</figcaption></figure>

<figure><img src="image_19.png" /><figcaption>Alkaline phosphatase - crop</figcaption></figure>

<figure><img src="image_20.png" /><figcaption>N Acetyl Glucosaminidase - crop</figcaption></figure>

<figure><img src="image_21.png" /><figcaption>Urease - crop</figcaption></figure>

<figure><img src="image_22.png" /></figure>
# Impact of Cu on enzymatic activities : Literature controversy

## ✓ Differences in experimental conditions

<figure><img src="image_23.png" /></figure>

### Sieved soil vs undisturbed cosmes

- microbial physiological status

- physical protection on soil microorganisms

- availability of copper

<figure><img src="image_24.png" /></figure>

### High Cu concentration vs agronomic reality

- Status of copper

- Distribution of copper
# Distribution of inoculated copper in microcosms

<figure><img src="image_25.png" /><figcaption>Content (mg) after equilibration</figcaption></figure>
Cu distribution in cosmes

<figure><img src="image_26.png" /></figure>
Evaluation of the copper impact on the descriptors of the microbial communities

<figure><img src="image_27.png" /></figure>
Conclusion

✓Spatiotemporal variability of enzymatic activities ranged from 6 to 95 % in referenced systems

✓Total enzymatic activities are higher in meadow related to soil biomass increase

✓ Anova analysis shows :

<figure><img src="image_28.png" /></figure>

Agricultural practices

<figure><img src="image_29.png" /></figure>

Sampling date (including season and plant cover)

<figure><img src="image_30.png" /></figure>

No copper effect
Conclusion

✓Enzymatic activities as indicator of soil « quality »?

✓Links between microbial communities structure and
functional diversity?

✓Enzymatic activity of interest ?

<figure><img src="image_31.png" /></figure>

stage of organic matter decomposition ?

✓ Methodological strategies for Soil Science :

<figure><img src="image_32.png" /></figure>

pH?

<figure><img src="image_33.png" /></figure>

Substrate?

<figure><img src="image_34.png" /></figure>

spectrophotometry versus fluorimetry?

<figure><img src="image_35.png" /></figure>

Units?

✓ Agronomic decision tools?
Thank you for your attention