Straw mulching is an effective measure to improve soil properties, crop growth, and yield. To further understand the advantage mechanisms of straw mulching, a field experiment with seven straw mulching levels (0 to 18 000 kg ha
-1) was
conducted to study the effects of straw mulching on maize (
Zea mays
L.) photosynthesis and rhizosphere soil microecological
environment. Results showed that maize chlorophyll content was evidently affected by straw mulching, and the
highest chlorophyll content was at 12 000 kg ha
-1 (M4). Straw mulching could significantly improve the photosynthetic
characteristics of maize, and the difference between M4 and 0 kg ha
-1 (M0) was significant. There was as trend change in soil
microbe quantity; it first increased and then decreased with increasing straw mulching levels, and the most suitable straw
mulching level for different types of microorganisms was 9000 kg ha
-1 (M3) or M4. Straw mulching significantly enhanced
soil enzyme urease, invertase, dehydrogenase, and protease activities, but when the straw mulching level reached a certain
level, the effect of straw mulching was no longer apparent and even had some adverse effects at straw mulching levels higher
than 15 000 kg ha
-1 (M5). Yield in M4 (10 186.84 kg ha
-1) was the highest compared with M0 (9365.12 kg ha
-1), and yield
significantly increased by 8.8%. Correlation analyses indicated that the soil microbe quantity and aforementioned enzyme
activities were all significantly and positively correlated with maize chlorophyll content, photosynthetic rate, and yield.
Findings suggest that straw mulching can apparently increase soil microbe quantity and enzyme activities and improve
crop photosynthesis and yield; the M4 level is the most reasonable straw mulching level in this study under comprehensive
consideration, and a straw mulching level that is too high (over M5) will have some negative effects.
