TITLE:
Planting Cotton in a Crop Residue in a Semiarid Climate: Water Balance and Lint Yield
AUTHORS:
Robert J. Lascano, Dan R. Krieg, Jeffrey T. Baker, Timothy S. Goebel, Dennis C. Gitz III
KEYWORDS:
Soil Water, Evapotranspiration, Cropping Systems, Semi-Arid, Wheat Residue
JOURNAL NAME:
Open Journal of Soil Science,
Vol.5 No.10,
October
26,
2015
ABSTRACT: Cotton (Gossypium
hirsutum L.) is planted on more land area than any other crop on the Texas
High Plains. Much of this area is considered highly erodible and requires a
conservation compliance program to participate in government farm programs.
Because this region is semiarid and because irrigation water is increasingly
limited, water conservation and efficient use of water are necessary to
maximize cotton lint yields. One popular conservation compliance practice used
is to plant cotton into a chemically terminated small grain crop, i.e., residue that provides wind
protection to the cotton seedlings. Our hypothesis was that in a semiarid
region the use of a small grain cover crop under irrigated conditions would use
more water than it conserves compared to conventional tilled cotton, thus
reducing cotton lint yields. To test the hypothesis separate field studies over
two growing seasons and on two soil textures, a loamy fine sand and a clay
loam, were conducted. The main treatments were tillage systems (conventional
and conservation using terminated wheat residue). The two split plot treatments
were water supply based on replacement of calculated grass reference
evapotranspiration (ETo). Tillage did not affect the amount of water
used by the cotton crop at either location ( 0.05)
except for an 80% ETo irrigation treatment at a single location
where the bare soil treatment used 10% more water than the residue treatments
for both years. The residue treatment decreased (P o single irrigation treatment in which the residue
treatment yielded 14% more lint than the bare soil treatment. The use of
terminated wheat residue had no impact on soil water storage during any part of
the year. During a 5-month period associated with wheat growth, the wheat
evapotranspiration was 20 to 40 mm more water (P