Many producers have eliminated tillage as they have bought strip-till equipment for planting cotton and other crops. Our research on cotton has shown that attention to every detail is important to high yields.
Cotton is often strip-tilled back into old cotton residue and some farmers have gone back over the old row several years in a row to take advantage of residual fertilizer, beds, controlling traffic and to maintain the old subsoil slot.
We began looking at the effects of nematodes on cotton yield in strip-tillage several years ago. We assumed that the cotton plant would survive for several weeks into the fall and winter after harvest, allowing nematode survival on live plant roots.
Our first look at reniform nematode numbers in-row versus row middles on mowed cotton stubble in January showed more than 60 percent more nematode numbers in-row as compared to row middles.
Cotton was strip-tilled planted in-row and in row middles in May of that year resulting in 23 percent more cotton yield when planted in row middles as compared to planting over old rows due to less nematode damage.
Nematode levels were still higher at the end of the season by about 25 percent from in-row planted samples as compared to that planted in row middles.
The second year of studies showed much the same trend and data from 2000 shows reniform nematode numbers from a late July sampling were about 40 percent less in cotton planted in row middles versus that planted over the old row.
This data indicates that it is important to remove cotton plants as soon as possible after harvest if strip-tillage is to be done the next year over the old row.
Since cotton is a perennial, nematodes can survive as long as cotton stalks are alive in the field. Pulling stalks can be a viable way to reduce nematode numbers for the next crop, often resulting in higher yields.