Bastida Felipe, Kandeler Ellen, Hernández Teresa, García Carlos
CEBAS-CSIC, Department of Soil and Water Conservation, Campus Universitario de Espinardo, 30100 Espinardo, Murcia, Spain.
Microb Ecol. 2008 May;55(4):651-61. doi: 10.1007/s00248-007-9308-0.
Microbial ecology is the key to understanding the function of soil biota for organic matter cycling after a single amendment of organic waste in semiarid soils. Therefore, in this paper, the long-term effect (17 years) of adding different doses of a solid municipal waste to an arid soil on humus-enzyme complexes, a very stable and long-lasting fraction of soil enzymes, as well as on microbial and plant abundance, was studied. Humic substances were extracted by 0.1 M pH 7 sodium pyrophosphate from soil samples collected in experimental plots amended with different doses of a solid municipal waste (0, 65, 130, 195, and 260 t/ha) 17 years before. The activity of different hydrolases related with the C (beta-glucosidase), N (urease), and P (alkaline phosphatase) cycles and with the formation of humic substances (o-diphenol oxidase) were determined in this extract. The density and diversity of plant cover in the plots, as well as the fungal and bacterial biomass (by analyzing phopholipid fatty acids) were also determined. In general, the amended plots showed greater humic substance-related enzymatic activity than the unamended plots. This activity increased with the dose but only up to a certain level, above which it leveled off or even diminished. Plant diversity and cover density followed the same trend. Fungal and bacterial biomass also benefited in a dose-dependent manner. Different signature molecules representing gram+ and gram- bacteria, and those corresponding to monounsaturated and saturated fatty acids showed a similar behavior. The results demonstrate that organic amendment had a noticeable long-term effect on the vegetal development, humic substances-related enzyme activity and on the development of bacteria and fungi in semiarid conditions.
微生物生态学是理解半干旱土壤中单次添加有机废弃物后土壤生物群落在有机质循环中功能的关键。因此，本文研究了向干旱土壤中添加不同剂量固体城市垃圾17年的长期影响，包括对腐殖质 - 酶复合物（土壤酶中一种非常稳定且持久的组分）以及微生物和植物丰度的影响。通过0.1M pH 7的焦磷酸钠从17年前用不同剂量固体城市垃圾（0、65、130、195和260吨/公顷）改良的试验地采集的土壤样品中提取腐殖物质。在该提取物中测定了与碳（β - 葡萄糖苷酶）、氮（脲酶）和磷（碱性磷酸酶）循环以及腐殖物质形成（邻二酚氧化酶）相关的不同水解酶的活性。还测定了试验地植物覆盖的密度和多样性，以及真菌和细菌生物量（通过分析磷脂脂肪酸）。总体而言，改良后的试验地显示出比未改良试验地更高的与腐殖物质相关的酶活性。这种活性随剂量增加，但仅到一定水平，超过该水平后趋于平稳甚至下降。植物多样性和覆盖密度遵循相同趋势。真菌和细菌生物量也以剂量依赖的方式受益。代表革兰氏阳性菌和革兰氏阴性菌的不同特征分子，以及对应于单不饱和脂肪酸和饱和脂肪酸的分子表现出类似行为。结果表明，在半干旱条件下，有机改良对植物发育、与腐殖物质相关的酶活性以及细菌和真菌的发育具有显著的长期影响。
