棉隆对苹果连作土壤微生物及平邑甜茶幼苗生长的影响

以生产上常用苹果砧木——平邑甜茶为试材,盆栽条件下研究了棉隆微粒剂对苹果连作土壤微生物及平邑甜茶幼苗生长的影响。结果表明:与重茬(对照CK)相比,棉隆处理极显著(P0.01)降低了连作土壤中真菌数量,降幅达58.8%,细菌和放线菌数量分别显著(P0.05)降低15.3%、8.5%,细菌/真菌增加108.8%,放线菌/真菌增加124.2%;棉隆使连作条件下平邑甜茶单株幼苗根系长度、根表面积、根体积和根系活力分别提高421.4%、426.5%、171.7%、48.8%。平邑甜茶植株叶面积以及叶片中叶绿素a、b含量、净光合速率均极显著提高,分别增加162.6%、14.9%、15.0%、24.0%,叶片同化能力增强;植株长势增强,株高和地径均极显著提高,植株地上干鲜重和地下干鲜重也得到了极显著性增加,最高增加幅度达2.2倍。综上,棉隆处理后苹果连作土壤中微生物数量降低,而细菌与真菌比值、放线菌与真菌比值增加,平邑甜茶幼苗植株长势增强,棉隆可有效减轻苹果连作障碍发生。

Effects of dazomet on edaphon and growth of Malus hupehensis rehd. under continuous apple cropping

ARP (Apple replant problem, ARP), which is also known as the continuous cropping obstacles of apple, influences the cultivation of replanted fruit trees. It occurs in all major apple planting regions throughout the world. Generally, it is believed that both biotic and abiotic factors act together to cause ARP, and that the biotic factors are recognized as the main cause of continuous cropping obstacles. This study aims to examine the responses of Malus hupehensis Rehd. and edaphon to dazomet, which was used to alleviate ARP, and to develop an effective method to prevent and cure ARP. The study was carried out in 2012 at the State Key Laboratory of Crop Biology and College of Horticulture of Shandong Agricultural University. The trees were planted in pairs in containers filled with loamy sand. The apple sick soil was originated from a remediate 20-year-old apple orchard. The soil was mixed with dazomet at the ratio of 0.5 g/kg before tree planting. Trees grown in the soil untreated with dazomet served as the control. Trees were dripirrigated consistently. The results showed that compared with the control, dazomet inhibited the growth of fungi, actinomycetes and bacteria under continuous cropping conditions. Dazomet treatments noticeably decreased the numbers of fungi, bacteria and actinomycetes by 58.8% (P < 0.01), 15.3% and 8.5% (P < 0.05), respectively. Therefore, dazomet had the most inhibition effect on fungi, and the lowest on actinomycetes. With respect to the ratio of bacteria (actinomycetes) to fungi,the ratio of bacteria and actinomycetes to fungi increased by 108.8% and 124.2%, respectively. Compared with control, the dazomet had significantly increased the length of roots, surface area of roots, total roots volume and root activity by 4.2, 4.3, 1.7, 0.49 times, respectively. The dazomet generally enhanced root biomass and improved the function of root under continuous cropping conditions. All these differences in content were statistically significant (P < 0.01). The roots play crucial roles in plant. The roots affect the growth and development of aboveground plant, which inclued the growth of foliage, starkrimsom of leaves, forming of flower buds and the reproductive growth of trees. The assimilation ability of leaves increased upon treated with dazomet under continuous cropping conditions. Compared with the control, the area of leaves, content of chlorophyll a, content of chlorophyll b and net photosynthetic rate significantly (P < 0.01) increased by 162.6%, 14.9%, 15.0%, 24.0%, respectively, after treated with dazomet. Plant height, geoxyl, root and shoot biomass showed a general growth (P < 0.01). The dry weight of the plant above the ground and underground also had extremely significant increase (P < 0.01). The highest increase rate was up to 2.2 times. In conclusion, the above-mentioned parameters show that dazomet improved vigor of trees by inhibiting the growth of fungi, actinomycetes, bacteria on replant disease sites.