Previous studies measured a long-term increase in infiltration rate
in a sandy loam soil with time when alfalfa (Medicago saliva L., cv.
WL514) was grown. Cotton (Gossypium hirsutum L.) was direct-planted
into alfalfa to determine if the high infiltration rates measured
under alfalfa culture could be maintained in cotton under either
a till or no-till system. Treatments were no-till or tillage to the 0.15 -
m depth just before the cotton was planted. Prior compaction levels
created by harvest traffic applied to the alfalfa made the soil loose
or compacted. Cotton was planted flat and irrigated as a basin. Infiltration
rates measured 2 h after water was applied and averaged
for the season were 101 (no-till, loose), 56 (till, loose), 82 (no-till,
compacted), and 42 mm/h (till, compacted). All the infiltration rates
were much higher than normally measured for cotton in these soils.
Water flow in the 5-yr-old alfalfa was determined to be mainly
through the soil macropore system. High infiltration rates measured
in the no-till cotton were also probably the result of flow through
the macropores
