The quantity and availability of N from green manures will considerabl
y affect the N management of a succeeding cotton (Gossypium hirsutum L
.) crop. This study was conducted to determine the N supplying capacit
y of crimson clover (Trifolium incarnatum L.), Austrian winter pea [Pi
sum sativum subsp. arvense (L.) Poir.], and rye (Secale cereale L.) to
cotton and their influence on cotton yield and fiber properties. Gree
n manure treatments (and a fallow check) with fertilizer N levels of 0
, 56, 112, and 168 kg ha-1 were compared for 3 yr on a Norfolk loamy s
and (fine-loamy, siliceous, thermic Typic Kandiudult). Soil moisture a
t planting was similar among the four green manure treatments. At the
0 N level, the legumes generally had higher soil NO3-N than rye or fal
low. Cotton grown following clover and pea with 0 kg ha-1 added N had
petiole NO3-N levels similar to those of rye and fallow with 56 kg N h
a-1. Fertilizer N had no influence on cotton yield in the pea winter c
over treatment. A quadratic regression equation best described the lin
t yield response following clover. For both rye and fallow treatments,
yield plateaued at 56 kg N ha-1. Green manures had little influence o
n fiber properties. The results indicate that legumes supply adequate
but not excessive N for modern cotton production and that incorporatio
n of rye into the production system does not affect N fertilization re
quirements.