新疆和田绿洲耕地阈值预估

[目的]在西北干旱区,因开垦耕地,绿洲不断扩张,挤占了生态用水,引起一系列生态与环境问题。以和田绿洲为例,用定量方法计算耕地面积阈值,可为当地水土资源开发及生态保护提供理论依据。[方法]水土平衡法。[结果]结果表明,P=75%时,2010、2020、2030年和田绿洲的耕地面积阈值分别为13.83×104、16.78×104、16.50×104 hm2;P=50%时,2010、2020、2030年和田绿洲的耕地面积阈值分别为14.95×104、18.08×104、17.78×104 hm2。如果不采取有效措施控制耕地扩张,2020、2030年耕地面积将分别超过P=75%时耕地面积阈值2.78×104 hm2、5.07×104 hm2。即使采取高效节水技术,2020年及2030年种植业需水量将由2010年的19.77×108 m3增加到20.82×108、21.95×108 m3,生态需水量及入塔里木河水量将无法得到保证,这必将危及和田河流域,甚至塔里木河流域的生态系统安全与稳定。[结论]耕地超过耕地阈值时,不仅危及和田绿洲的生态安全,同时因耕地扩张加大水资源消耗,和田河汇入塔里木河水量减少,威胁着塔里木河生态与环境安全。为此建议制定严格措施,加强干旱区绿洲-荒漠过渡带的保护,严禁以各种名义的开荒。     

塔克拉玛干沙漠边缘典型绿洲城市宜居性分析

分析城市的宜居性可以为改善当地人居环境提供科学依据。以塔克拉玛干沙漠边缘典型绿洲城市为研究对象,运用层次分析法从社会、经济、环境3个方面分析研究区2002～2011年间的宜居性。研究结果表明,各城市的宜居度存在年际变化且有差别,并不都是稳步上升;库尔勒市的社会、经济、环境及综合宜居性均处于5个城市之首;宜居城市排名为库尔勒市>阿克苏市>阿图什市>喀什市>和田市。     

河西古浪县沙漠绿洲边缘土地合理利用对策

通过对河西古浪县腾格里沙漠南缘新垦绿洲区农业生产、土地与水资源利用现状,区域种植结构、经济发展水平与生态环境建设等内容进行调查分析,结果显示：项目区农业用地资源有限,水资源短缺,农作物品种单一产业结构简单,经济作物种植面积小,严重制约了区域生态农业整体发展水平。为了改善绿洲边缘生态环境和发展新垦人工绿洲农业生产,提高区域土地利用效率,推广节水型生态农业,增加区域经济收益,采用在项目区增加种植经济植物、节水型农作物品种的种植面积,发展优质牧草和地膜种植面积,扩大养殖业等试验研究的方法和措施,调整区域产业种植结构,改革现行农田耕作技术,改善绿洲边缘生态环境,提高区域土地利用效率和增强土壤肥力,达到明显的经济效益,为沙漠绿洲边缘发展生态农业和促进区域农业可持续发展起到示范作用。     

绿洲不同生态区资源变异及水土开发模式研究

水土资源的开发始终是绿洲农业发展的核心问题,通过对冲积洪积扇绿洲、冲积平原绿洲、干三角洲绿洲等绿洲不同生态区水土资源空间组合差异及水土资源的开发特点分析,提出了不同生态区水土开发利用要点,认为在冲积扇及冲积平原区域,通过合理井灌井排、人工种植草场及机械化除盐等技术进行恢复盐渍化弃耕地为主来扩大耕地,避免重新开荒后又弃耕的发生;在流域下游干三角洲及沙漠边缘区域,通过高效节水技术防止地下水位抬升,造成土壤次生盐渍化,为绿洲农业资源的优化配置和农业结构调整提供理论依据。     

Policy incentives for reducing nitrate leaching from intensive agriculture in desert oases of Alxa, Inner Mongolia, China

Excessive irrigation and nitrogen applications result in substantial nitrate leaching into groundwater in intensively cropped oases in desert areas of Alxa, Inner Mongolia. An integrated modelling approach was developed and applied to compare policy incentives to reduce nitrate leaching. The integrated model consists of a process-based biophysical model, a meta-model, a farm economic model and an assessment of policy incentives. The modelling results show that there are “win-win” opportunities for improving farm profitability and reducing nitrate leaching. We found that 4471 Yuan ha⁻¹ of farm gross margin could be obtained with a reduction in nitrate leaching of 373 kg ha⁻¹. Farmers’ lack of knowledge about water and nitrogen in soil, and on crop requirements for water and nitrogen could explain the differences, so that agricultural extension is an appropriate policy incentive for this area. When the economic optimum is obtained reductions in nitrate leaching are not achievable without profit penalties and there is a “trade-off” relationship between farm profitability and groundwater quality protection. The combination of low elasticity of nitrate leaching and large elasticity of farm gross margin against water price increases results in very high costs for reducing nitrate leaching (105.6 Yuan kg⁻¹). It is suggested that if the water price increases were coupled with subsidies for adopting nitrate leaching mitigation practices, environmental gains could come at a lower cost.     

营养水平对策勒黑羊羔羊生产性能的影响

研究营养水平(A因子:A1为1.0倍NRC、A2为0.9倍NRC、A3为0.8倍NRC)和性别(B因子:B1为公羔、B2为母羔)对策勒黑羊羔羊生产性能的影响及经济效益分析。结果表明,A1B1组羔羊试验末体重分别较A1B2组、A2B1组、A2B2组、A3B1组、A3B2组羔羊提高6.17%、7.44%、12.84%、14.29%、17.22%;A1B1组羔羊平均日增重分别较A1B2组、A2B1组、A2B2组、A3B1组、A3B2组羔羊提高20.87%、17.06%、34.89%、37.35%、39.62%;A1B1组羔羊料肉比分别较A1B2组、A2B1组、A2B2组、A3B1组、A3B2组羔羊降低28.24%、23.96%、62.47%、63.84%、62.96%。根据经济效益分析可知,A1B1组羔羊纯收入分别较A1B2组、A2B1组、A2B2组、A3B1组、A3B2组羔羊增加17.13%、28.19%、41.58%、40.24%、42.69%。由试验可知,采用1.0倍NRC的饲粮饲喂的策勒黑羊公羔羊生产性能和经济效益较高。     

策勒黑羊BMPR-IB基因多态性与产羔数的相关性研究

以BMPR-IB基因为策勒黑羊多羔性状的候选基因,采用PCR-RFLP方法对策勒黑羊BMPR-IB基因的多态性进行分析,研究其与产羔数的关系。在随机选取的100只策勒黑羊中BB、B+和++基因型对应的每胎产羔数分别为3.00、2.66和1.98只,BB基因型与B+基因型产羔数极显著高于++基因型(P<0.01),BB基因型与B+基因型之间产羔数差异不显著(P>0.05)。因此,在策勒黑羊中B等位基因对产羔数有显著影响,可以作为分子遗传标记之一用于对策勒黑羊产羔数的选择。     

绿洲区滴灌施磷对苜蓿地肥力和磷素利用率的影响

为探讨绿洲区滴灌施磷对苜蓿磷素利用效率的影响及其土壤肥力变化规律,在石河子绿洲区滴灌苜蓿田设不同的施磷处理,即1次性施180 kg·hm^-2磷肥（L₁）、1次性施360 kg·hm^-2磷肥（H₁）、均分3次施180 kg·hm^-2磷肥（L₂）、均分3次施360 kg·hm^-2磷肥（H₂）及不施肥（CK）,对各处理下苜蓿田土壤肥力和磷素利用效率进行测定和分析。结果表明,较CK相比,L₂处理可显著提高耕作层平均有机质含量（P<0.05）,H₁和H₂处理可显著提高耕作层平均全磷含量（P<0.05）。各处理均可显著提高耕作层平均速效磷含量（P<0.05）。各处理对平均碱解氮含量及pH值无显著影响。‘新牧2号’苜蓿（Medicago sativa ‘Xingmu No.2’）磷素利用效率最高的为L₁和L₂处理（F=17.02）,‘三得利’（Medicago sativa ‘Sanditi’）为L₂处理（F=14.33）。因此,建议绿洲区苜蓿栽培滴灌施磷的最佳模式为均分3次施用180 kg·hm^-2磷肥。     

叶尔羌河,喀什噶尔河流域的绿洲化和沙漠化环境问题

本文以该流域的绿洲化和沙漠化环境问题为主线，通过对沙漠与绿洲过渡带的评价，合理利用水资源的评价，河床改造利用的评价，阐述了荒漠生态系统的被破坏和绿洲生态系统的被建立。     

Temporal and spatial variations of net primary productivity and its response to groundwater of a typical oasis in the Tarim Basin,China

Net primary productivity (NPP) of the vegetation in an oasis can reflect the productivity capacity of a plant community under natural environmental conditions. Owing to the extreme arid climate conditions and scarce precipitation in the arid oasis regions, groundwater plays a key role in restricting the development of the vegetation. The Qira Oasis is located on the southern margin of the Taklimakan Desert (Tarim Basin, China) that is one of the most vulnerable regions regarding vegetation growth and water scarcity in the world. Based on remote sensing images of the Qira Oasis and daily meteorological data measured by the ground stations during the period 2006-2019, this study analyzed the temporal and spatial patterns of NPP in the oasis as well as its relation with the variation of groundwater depth using a modified Carnegie Ames Stanford Approach (CASA) model. At the spatial scale, NPP of the vegetation decreased from the interior of the Qira Oasis to the margin; at the temporal scale, NPP of the vegetation in the oasis fluctuated significantly (ranging from 29.80 to 50.07 g C/(m²•month)) but generally showed an increasing trend, with the average increase rate of 0.07 g C/(m²•month). The regions with decreasing NPP occupied 64% of the total area of the oasis. During the study period, NPP of both farmland and grassland showed an increasing trend, while that of forest showed a decreasing trend. The depth of groundwater was deep in the south of the oasis and shallow in the north, showing a gradual increasing trend from south to north. Groundwater, as one of the key factors in the surface change and evolution of the arid oasis, determines the succession direction of the vegetation in the Qira Oasis. With the increase of groundwater depth, grassland coverage and vegetation NPP decreased. During the period 2008-2015, with the recovery of groundwater level, NPP values of all types of vegetation with different coverages increased. This study will provide a scientific basis for the rational utilization and sustainable management of groundwater resources in the oasis.