栽植生姜对不同种植模式下紫色土微生物生物量及水解酶活性的影响

研究了岷江下游紫色丘陵区玉米+红薯间作、大豆单作、生姜连作、水稻-紫云英轮作等4个典型种植模式下栽植生姜后土壤微生物生物量碳、氮、磷含量和水解酶活性的变化特征.结果表明： 栽植生姜显著降低了4个种植模式下土壤微生物生物量碳、氮和磷含量，但各种植模式之间存在较大差异.其中，玉米+红薯间作和水稻-紫云英轮作模式下土壤微生物生物量碳、氮的下降幅度明显低于大豆单作与生姜连作模式，但土壤微生物生物量磷下降幅度明显较高.栽植生姜显著降低了土壤酸性磷酸酶活性，其下降幅度以玉米+红薯间作模式最大，水稻-紫云英轮作模式最小；土壤转化酶活性在生姜连作模式下显著降低；土壤脲酶活性在大豆单作、生姜连作和水稻-紫云英轮作模式下均显著降低.相对于其他模式，栽植生姜使玉米+红薯间作模式下的土壤维持了较高的转化酶和脲酶活性.

Ecological services value of forest ecosystem in eastern Qilian Mountains based on emergy theory

By using emergy analysis theory and method, this paper analyzed the emergy flow and ecological value of the forest ecosystem in Haxi area in eastern part of Qilian Mountains’ northern slope. In the study area, the input energy flow of forest ecosystem was larger than the output energy flow, indicating that the energy was accumulating in the forest ecosystem. Through energy flow, low-quality energy transformed into high-quality energy, and the environment of the ecosystem was relatively safe. The total emergy of five ecological services, including organic matter production, water conservation, soil maintenance, CO2 fixation, and air purification was 9.35 ×1021 sej, and the total emergy monetary value was 7.77×108 US$. The emergy monetary value of water conservation and soil maintenance was apparently higher than that of other services. The monetary value of each service was in the order of water conservation > soil maintenance > air purification > organic matter production > CO2 fixation. Water conservation was the most important ecological service in the study area, and the proportion of the emergy monetary value of water conservation was 69.6%. Among different vegetations, shrub land had the largest value of water conservation, while arbor forest had the largest value of water conservation per unit area.