水肥条件对煤矸石土壤上两种牧草光合及生物量的影响
马 戌1, 王进鑫2, 张玉玉1, 胡杭丽2

(1.西北农林科技大学 水土保持研究所, 陕西 杨凌 712100; 2.西北农林科技大学 资源环境学院, 陕西 杨凌 712100 )

煤矸石; 净光合速率; 生物量; 水肥耦合; 植被恢复; 模型寻优

Effects of Water and Fertilizer Conditions on Photosynthesis and Biomass of Two Forage Grasses in Coal Gangue Soil
MA Xu1, WANG Jinxin2, ZHANG Yuyu1, HU Hangli2

(1.Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; 2.College of Natural Resources and Environment, Northwest A & University, Yangling, Shaanxi 712100, China)

gangue field; net photosynthetic rate; biomass; water-fertilizer coupling; vegetation restoration; model optimization

备注

西北干旱荒漠区煤矸石排放数量巨大,占用了大量土地且造成了多种污染,为了解决植被恢复面临的水分短缺、蒸发力强和养分贫瘠等困难,保证煤矸石山土壤上典型牧草能够正常存活和生长良好,试验采用二次通用旋转组合设计,测定了不同水肥条件下草木樨和蒙古冰草的光合及生物量并建立了水肥耦合回归模型,得到了煤矸石山植被恢复中2种牧草的最优水肥方案。结果 表明:土壤水分对2种牧草的光合及生物量最敏感; 磷肥对草木樨生长的贡献大于氮肥,氮肥对蒙古冰草生长的贡献大于磷肥; 草木樨的光合及生物量均远大于蒙古冰草。西北煤矸石山植被恢复的草本植物首选草木樨,其最优水肥方案为土壤相对含水量68.44%～71.84%,施氮量82.09～102.92 kg/hm2,施磷量139.92～192.58 kg/hm2。其次是蒙古冰草,其最优水肥方案为土壤相对含水量65.33%～71.11%,施氮量138.40～172.62 kg/hm2,施磷量82.09～117.91 kg/hm2。试验结果为西北干旱荒漠区采煤迹地植被恢复提供了理论依据和实践指导。

Coal mining activities produce a huge amount of coal gangue and other solid wastes, which are deposited in piles and replace a large area of arable land into bare land. Moreover, these mining activities are more severe in the arid desert area of northwest China where scarcity of water and nutrients plays a significant role in the vegetation restoration. A quadratic general rotary combination design was adopted to examine the influence of different doses of water and fertilizers on the photosynthesis and biomass of Melilotus albus Desr. and Agropyron mongolicum Keng grown in coal mine spoils. Moreover, to identify a suitable water and fertilizer doses for vegetation restoration in the coal gangue area of northwest China. The experimental results showed that soil water was most important factor for the net photosynthesis rate and biomass production of the two forage grasses, and also demonstrated that the influence of phosphorus fertilizer on growth of Melilotus albus Desr. was higher than that of nitrogen fertilizer, whereas the influence of nitrogen fertilizer on growth of Agropyron mongolicum Keng was higher than that of phosphorus fertilizer. The net photosynthesis rate and biomass production of Melilotus albus Desr. were greater higher than Agropyron mongolicum Keng, suggesting that planting Melilotus albus Desr. for revegetation purpose in the northwest coal gangue area with optimum water and fertilizer doses is the effective practice, which follows the pattern: soil relative water content 68.44%～71.84%, nitrogen application 82.09～102.92 kg/hm2, phosphorus application 139.92～192.58 kg/hm2. In addition, vegetation with Agropyron mongolicum Keng using soil relative water content of 65.33%～71.11%, nitrogen application of 138.40～172.62 kg/hm2, phosphorus application of 82.09～117.91 kg/hm2 can also be considered as a second option.