If you are going to cover part of that area with cement there is no reason to spend any time, energy, or money on "weed" control, just dig out the soil in that area and put down the base for the patio and then the cement.

For the are to be sodded you should make the soil into a good healthy soil that will row a good healthy turf and that means starting with a good reliable soil test. Contact your local office of your Louisiana State Universities Cooperative Extension Service about having this done.

http://www.lsuagcenter.com/portals/our_offices/departments/spess/servicelabs/soil_testing_lab/

A few other simple soil tests you can do are,

1) Soil test for organic
material. From that soil sample put enough of the rest to make a 4 inch level in
a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and
replace the lid, tightly. Shake the jar vigorously and then let it stand for 24
hours. Your soil will settle out according to soil particle size and weight.
For example, a good loam will have about 1-3/4 inch (about 45%) of sand on the
bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above
that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole
1 foot square and 1 foot deep and fill that with water. After that water drains
away refill the hole with more water and time how long it takes that to drain
away. Anything less than 2 hours and your soil drains’ too quickly and needs
more organic matter to slow that drainage down. Anything over 6 hours and the
soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful
of your slightly damp soil and squeeze it tightly. When the pressure is
released the soil should hold together in that clump, but when poked with a
finger that clump should fall apart.

4) Smell. What does your
soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant
odor? The more organic matter in your soil the more active the soil bacteria
will be and the nicer your soil will smell, to a point. Too much organic matter
can be bad as well.

5) Life. How many
earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5,
according to the Natural Resources Conservation Service, indicates a soil that
is not healthy.

Once the soil is made into a good healthy soil the unwanted plant growth may be a thing of the past

kimmq is kimmsr

Was the yard flooded at some recent point? What it looks like you've got is a lot of dead grass and some other grasses trying to grow. As kimmsr says, why do double work? Put in your patio (which will probably entail a bit more damage to the lawn), and then work on the yard. Rake up all the dead stuff and start again.