Lesson 8: mechanical control

What is the goal of minimum till/no till

You are trying your best to not disturb the soil profile.

What have herbicide tolerant crops done to no-till?

They have made it a more attractive option. No till requires a lot of chemical inputs

What is mechanical control?

The use of tools, equipment, or hands to physically disturb weeds.

What are the two types of mechanical tillage?

1. primary tillage (a deep pass that really digs up soil)

2. Secondary tillage (tilling in between the rows/crops that is shallow)

How does tillage control weeds outside destroying them?

It can bring up seeds to germinate to kill later or it can burry seeds so they never germinate.

When is tillage ineffective?

Wet soil that bogs you down, certain row crops do not like secondary tillage (potatoes, onions, etc), it can actually promote weed germination, it can reduce soil moisture content.

When in no till least effective?

In its first years when the field does not have a good matt of biomass.

What are the most common mechanical weed seed controls?

1. mowing

2. hoeing

3. tilling

4. no-till biomass

5. harrington seed destuctor

6. chaff lining/burning

7. 
   

What types of plants is mowing best for?

It is good for small annuals. It can also be used to deplete perennial carbohydrate stores.

When is it best to mow a perenial?

It is best in spring/summer to use up stores before it goes into winter/fall where it needs carbohyrdate stores.

Why are harrington seed destructors not on everything?

Expensive to buy, install, and require certain combines (not effective in cotton pickers/peanut inverters)

How is chaff lining effective?

You line up all the weed seed and treat it with herbicide or burn it (requires extreme temperatures). its also really cheap

What are the main downsides of chaff carts?

They take away biomass that would have been returned to soil. They also take a lot of passes to deal with all the chaff.

Why is hand pulling not used commonly?

It is extremely expensive to hire people to go pick weeds.

Where is hand picking mainly used?

In high value crops or developing countries.

What is goal and what can mulch be made out of?

Mulch goal is to block sunlight preventing weed germination. It can be plastic mats, woodchips, stones, anything really

Where is mulching not practical?

In agronomic systems outside using cover crop residues

Why is steam sterilization mainly used in greenhouses?

It has a lot of licensing requirements, and it is not scalable well.

Why is soil solarization not great?

It takes weeks to take effect and it cost alot to place out sheets of clear tarp.