Varietal choice to limit weed development in silage corn

Case studies - Chamber of Agriculture Occitanie - Aglae - Guy Doléac (2012) - Weed management

Arable crops Protein autonomy Climate resilience Crop-livestock farming Weed control in arable crops Weed control

Hautes-Pyrénées (department)

55 ha

2

Loamy plain to clay-loamy

Arable crops

Crop-livestock farming

Irrigated system

Feedback from Guy Doléac, within the framework of the Aglae project. He presents his criteria for selecting silage corn varieties depending on their place in the rotation.

Motivations

I have a crop-livestock farming operation that includes a poultry unit and a dairy product processing unit.

The management strategy I have implemented aims to achieve objective of protein autonomy for feeding my herd. I therefore also have plots of grasslands, mixed croppings, silage corn, sunflower and soybean.

I prioritize varieties with high nutritional value and strong initial vigor.

The choice of varieties based on these criteria also serves as a lever to reduce weed pressure, especially on corn and soybean plots.

Implementation

Varietal choice: my way of doing

Implemented since 2012.

My selection criteria for silage corn

Good nutritional value

Strong initial vigor:

- I need a vigorous corn from the start, which develops quickly to be able to shorten the cycle and facilitate early establishment of mixed cropping (between October 10 and 25)

- reduce risks of attack by corn borers and wireworms

- a crop that establishes quickly creates faster competition with weeds

Plant habit:

- drooping habit

- covers the inter-row faster compared to an upright habit and thus helps limit the development of potential weeds, especially black nightshade, amaranths and ryegrass.

The varieties I use for silage corn

For corn at the head of the rotation: index 540, late group

very good nutritional value
good digestibility
strong initial vigor
drooping habit

For corn following a mixed cropping: index 400/450, mid-late group

good nutritional value
strong initial vigor
upright habit

"This year (2019), I chose to use the variety PR34B39 for corn at the head of the rotation and P0319 for corn following a mixed cropping. Although its habit is upright, it has good nutritional value and its strong initial vigor means it covers the soil quite quickly and still limits weed development. In general, I have observed fewer weed problems after a mixed cropping."

The variety I use for grain corn

Index 400/450, mid-late group

strong initial vigor
semi-drooping habit

"This year (2019), I chose to use the variety P9838 for grain corn."

Benefits and points of caution

Benefits

Allows greater protein autonomy
Allows early establishment of following crops
Limits weed development in inter-rows
Reduces risks of attack by certain pests

Points of caution

Limited choice of varieties based on selected criteria

My tips for success

Choose a variety adapted to your region and soil type
Do not choose a later variety just to favor drooping habit
Work on a soft and drained soil
For more effectiveness, combine with other levers

My perspectives

Equip with a more efficient hoe to perform more mechanical weeding
Set up trials to fight against corn borer and sesamia

Leviers évoqués dans ce système

My results

Agro-environmental

Reduction of herbicide TFI (0 to 10%)
Reduction of weed pressure
Reduction of disease pressure
Stability of pest pressure

Social

Stability of spring workload
Increase in observation time

Economic

Stability of mechanization costs
Stability of net margin
Stability of implementation cost

Expert committee opinion

Evaluation according to the ESR analysis grid.

Efficiency

The objective is to increase the efficiency of available control methods through the development of technologies that improve their use or by better positioning. In this context, decision support tools and precision agriculture are included.