不同秸秆覆盖水平对砂姜黑土生物学性状的影响

Effects of Different Straw Mulching Levels on Biological Characteristics of Lime Concretion Black Soil

为明确秸秆覆盖对土壤生物学特性的影响,筛选出安徽淮北砂姜黑土区适宜的秸秆覆盖量,采用大田试验研究了7种秸秆覆盖水平M0（0 kg·hm^-2）、M1（3 000 kg·hm^-2）、m^2（6 000 kg·hm^-2）、M3（9 000 kg·hm^-2）、M4（12 000 kg·hm^-2）、M5（15 000 kg·hm^-2）和M6（18 000 kg·hm^-2）对玉米根际土壤微生物数量和酶活性的影响。结果表明,单位质量的土壤硝化细菌、氨化细菌和溶磷菌数量随秸秆覆盖量的增加呈先增加后下降的趋势,霉菌的数量随秸秆覆盖量的增加而增加。秸秆覆盖可显著增加土壤中的微生物数量,且不同种类微生物对应的最佳秸秆覆盖量存在一定的差异,其中吐丝期和灌浆中期单位质量的土壤溶磷菌数量和硝化细菌数量都以M4处理最高,氨化细菌数量以M3处理最高,霉菌数量以M6处理最高。土壤酶活性受秸秆覆盖的显著影响,但当秸秆覆盖量增加到一定程度,秸秆覆盖量的变化对土壤酶活性的影响不再明显。吐丝期和灌浆中期土壤中蔗糖酶、淀粉酶和磷酸酶活性以M4最高,过氧化氢酶活性以M3处理最高。土壤中硝化细菌、氨化细菌、溶磷菌、霉菌和总微生物数量与磷酸酶、过氧化氢酶、蔗糖酶和淀粉酶活性皆呈正相关关系。研究得出,秸秆覆盖在改善土壤生物学特性方面发挥着重要作用,但秸秆覆盖量过高则不利于土壤微生物数量和酶活性的增加,且不同种类微生物和酶对应的最佳秸秆覆盖量存在一定差异,秸秆覆盖量为9 000~12 000 kg·hm^-2时最有利于淮北砂姜黑土生物学特性的改善。

In order to clarify the effects of straw mulching on soil biological characteristics and screen out suitable straw mulch level in lime concretion black soil area of Huaibei in Anhui province, a field experiment with 7 straw mulching levels M0（0 kg·hm^-2）, M1（3000 kg·hm^-2）, m^2（6000 kg·hm^-2）, M3（9000 kg·hm^-2）, M4（12000 kg·hm^-2）, M5（ 15000 kg·hm^-2） and M6（18000 kg·hm^-2） was carried out to study the effects of straw mulching on maize rhizosphere soil microbial quantity and enzymes activities. The results indicated that the quantity of nitrobacteria, ammonifying bacteria and phosphate-solubilizing bacteria in soil had a change trend of first increased and then decreased with increasing straw mulching level, while the quantity of mould was increased with increasing straw mulching level. Straw mulching could significantly increase soil microbial quantity, and the most suitable straw mulching level for different kinds of soil microorganisms had some differences, the quantity of phosphate-solubilizing bacteria and nitrobacteria in M4 were the highest, the quantity of ammonifying bacteria in M3 was the highest, the quantity of mould in M6 was the highest, respectively at silking stage and middle of filling stage. Soil enzymes activities were significantly affected by straw mulching, while when the straw mulching level increased to a certain extent the effect of the change of straw mulching level on soil enzymes activities was no longer obvious. The activities of soil invertase, amylase and phosphatase in M4 treatment were the highest, and the activity of catalase in M3 treatment was the highest, respectively at silking stage and middle of filling stage. Correlation analyses indicated that the quantity of nitrobacteria, ammonifying bacteria, phosphate-solubilizing bacteria, mould and total soil microbial quantity were all positively correlated with the activities of phosphatase, catalase, invertase and amylase. All the findings suggest that suitable straw mulching level plays an important role in improving soil biological characteristics, while too high straw mulching level would bring some negative influences on increasing soil microbial quantity and enzymes activities, and the most suitable straw mulching level for different kinds of soil microbial quantities and enzyme activities have some differences,the quantity of 9000~12000 kg·hm^-2 is the best for improving lime concretion black soil biological characteristics in Huaibei area.