Garlic (
Allium sativum
L.) stalk is a byproduct and normally the waste of garlic production but now is thought a good
biological resource. It is necessary to utilize this resource
efficiently and reasonably to
reduce environment pollution and
achieve agricultural sustainable development. The allelopathy of decomposed garlic stalk at different ratios (0:100, 1:100,
3:100 and 5:100) was investigated in this study using lettuce (
L. sativa
var
. crispa
L.) as the allelopathic test plant. The
results are as follows: (1) Lower concentration of decomposed garlic stalk promoted lettuce plant growth, but higher
concentration inhibited growth. (2) The highest ratio of stalk to soil (5:100) significantly increased the root length and fres
h
weight of lettuce but decreased the shoot length and fresh weight. (3) Lower ratio of stalk to soil significantly increased the
content of protein and chlorophyll and the activity of plant enzymes. (4) Increasing the concentration of decomposed garlic
stalk increased the activity of soil urease and sucrase. It was concluded that the decomposed garlic stalk with lower
concentration could promote lettuce plant growth. This result provides a scientific basis for allelopathic study and
application of decomposed garlic stalk.