陇中半干旱区集雨限灌对马铃薯干物质积累和产量的影响

研究了大田条件下集雨有限补偿灌溉对旱区马铃薯干物质积累分配和产量的影响。结果表明:进行有限补充灌溉对旱作马铃薯有显著的增产效果,其经济系数也得到相应提高,与对照(不灌水)相比,补灌处理产量增幅在3.91%~21.21%之间,苗期补灌45 mm与90 mm对马铃薯产量的补偿效应显著;补灌马铃薯干物质积累量与对照相比无显著差异,但花后干物质的分配运转,苗期补灌处理比对照移动量大,转换率高,有利于花后薯块营养物质的积累;薯块膨大期补灌45 mm和90 mm,在干物质积累和花后干物质转化方面均低于对照,增产效果也并不显著。     

Genetic monitoring of deep‐water exploited banks of the precious Sardinia coral Corallium rubrum (L., 1758): useful data for a sustainable management

相似文献   

不同施肥水平下全膜双垄沟播玉米土壤酶活性及氮磷养分含量的动态变化

为进一步完善全膜双垄沟播玉米栽培技术体系,采用大田随机区组试验法,研究了不同施肥水平下全膜双垄沟播玉米土壤酶活性及氮磷养分含量的动态变化情况。结果表明：在玉米生长前期,土壤脲酶、碱性磷酸酶、蔗糖酶活性以及碱解氮、速效磷含量均呈现快速增长趋势。脲酶、蔗糖酶、过氧化氢酶活性和碱解氮含量均在拔节期达到最大值,碱性磷酸酶活性和速效磷含量在抽雄期达到最大值。在玉米生长后期,各种土壤酶活性和氮磷养分含量又呈降低趋势。土壤脲酶活性与氮磷养分含量,土壤碱性磷酸酶活性与速效磷含量均存在显著或极显著正相关关系,土壤蔗糖酶活性与氮磷养分含量也存在显著的正相关关系,而土壤过氧化氢酶活性与氮磷养分含量之间,土壤碱性磷酸酶活性与碱解氮之间无显著相关关系。西北干旱半干旱地区全膜双垄沟播玉米种植密度确定为6.75×10⁴株·hm^-2时,最佳施肥量为纯N 210 kg·hm^-2、P₂O₅ 168 kg·hm^-2。     

太湖地区农业源对水体氮污染的贡献——以宜溧河流域为例

宜溧河流域是太湖上游的主要集水流域,该流域的污染物排放是太湖污染负荷的重要来源。重点针对种植业、畜禽养殖业和水产养殖业三种农业污染源,基于统计年鉴、遥感解译、野外监测和调研等多种手段,对种植业、水产养殖业和禽畜养殖业分行业进行了氮污染负荷核算。结果表明,2013年宜溧河流域主要农业源氮污染负荷总量为6861 t,单位排放强度为22.2 kg·hm^-2;种植业和禽畜养殖业是宜溧河流域氮污染的主要来源,其中种植业源TN排放量最大,为3832 t,占总负荷的55.9%,种植业中蔬菜地对氮污染的贡献较大,TN排放量占总农业源负荷的18.7%;禽畜养殖业源TN排放量次之,占总负荷的34.4%;水产养殖业源TN排放量最小,占总负荷的9.8%.因此,针对宜溧河流域农业源氮污染的治理,在考虑禽畜养殖和水产养殖的同时,应以种植业污染尤其是菜地作为重点研究对象,制定合理的控制措施。     

邓下小流域植物多样性与主要植被类型土壤养分效应

以苏南丘陵区邓下小流域为研究区,针对目前小流域内植被物种多样性状况和水平,选择物种丰富度指数（33、Shannon—Weiner指数（SW）、Simpson指数（SP）和Pielou均匀度指数（J）作为物种多样性的测度指标,分析不同植物群落结构特征。对流域内现有主要植被类型（茶园、杉木林、马尾松林、毛竹林、水田和旱耕地共6种）以0—10cm,10—20cm,20～40cm和40～60cm分层挖土壤剖面,分析各植被类型下土壤养分效应,以期为小流域综合治理与植被恢复中植被模式选择提供理论指导。     

Water for irrigation or hydropower generation?—Complex questions regarding water allocation in Tanzania

The need for achieving efficient, equitable and sustainable use of water resources to meet water demands of different sectors is pressing, particularly in areas where water resources are dwindling. Along with this is the quest for having a good understanding of the value of water in its different uses. Using a simplified model derived from the residual imputation approach (the Change in Net Income Model) we assess the value of water in irrigated paddy and hydropower generation in the Great Ruaha River Catchment (GRRC) in Tanzania. The estimated productivity of water (PW) in irrigated paddy ranges from 0.059 to 0.250 kg/m³ (for withdrawn water) and 0.126 to 0.265 kg/m³ (for consumed water). The PW in hydropower generation is estimated to range from 0.45 to 1.68 kWh/m³. In monetary terms the value of water in irrigated paddy is estimated at 15.3 Tanzanian shilling (Tsh)/m³ (for water withdrawn) and 0.19 Tsh/m³ (for water consumed). The values of water for hydropower generation are relatively higher than for irrigated paddy, ranging from 59 to 226 Tsh/m³. Yet, irrigated paddy also supports livelihoods of about 30,000 agrarian families in the GRRC, with gross revenue of about Tsh 15.9 million per annum and GRCC paddy contributes about 14–24% of national rice production. We conclude that understanding the value of water in its alternative uses is key to fostering informed debate on water management and allocation, identifying the basis for making ‘agreeable’ trade-offs, the potential for improvement and creating linkages with water allocation options particularly in agricultural-based economies, where agriculture competes with other sectors and where water re-allocation decisions may involve large transfers of water from the sector generating the highest pro-poor returns (agriculture for this case) to the sectors generating the highest economic returns (hydropower generation and industrial uses).     

关于黄土高原径流农业发展的思考

径流农业实质上是增强人工对自然降雨时空分布不均的调控能力,实现高效用水的系列化技术体系。目前黄土高原径流农业的主要类型是控制径流非目标输出、径流在时间和空间上向农田聚集。为了促进黄土高原跨世纪农业发展和生态环境建设,有必要深化对径流农业内涵的认识,分区位科学规划和规范化利用径流资源,把径流利用、粮食生产、结构调整、生态环境建设有机结合起来,以小流域为单元,加强对径流资源网络化利用的系统研究。     

固化土集流面无侧限抗压强度影响因素研究

该文采用无侧限抗压强度作为反映指标,对影响固化土强度的剂量、龄期、密度、含水率、凝结时间和养护环境等主要因素进行研究,提出增强土壤固化剂集流面强度的措施。研究结果表明：固化剂集流面的剂量选择12％左右,养护龄期需要7 d以上,压实度控制在0.94以上。在同一密度下含水率为最优含水率的(80±5)%范围内时,固化土的强度达到最大。在混合料拌和好12 h内尽快完成施工。施工结束后,应立刻进行覆盖防蒸发处理,24 h后方可进行洒水或浸水养护。温度和湿度越高越有利于固化剂集流面强度的增长和外观的平整。     

温室集雨与集雨水高效利用研究

在半干旱偏旱区设置了清除土表杂草、红沙覆盖、废膜覆盖和日光温室棚面4种不同的集流面处理,结合日光温室秋冬茬黄瓜、番茄不同灌水量试验,通过水的转化效率探讨不同集流面的使用价值和提高水转化效益的适宜灌水量.结果表明:温室棚面的年产流率最高为85.4%,其次为废膜集流面45.4%,清除土表杂草集流面的年产流率仅有8.2%.从单方水集流费用看,清除土表杂草>红沙集流面>废膜集流面>日光温室棚面,平均集流费用为2.18元/m3,单座温室棚面(450 m2)集流面加上温室间隔区废膜集雨(600 m2),集雨水总量可达到197 m3,能够满足温室一茬黄瓜和一茬番茄的需水量.     

旱农区不同种植模式作物最佳补灌时期和适宜补灌量研究

The effect of supplementary irrigation with catchment rainfall on crop yield increment and its water use efficiency was studied on upland field with different cropping patterns to make full use of the natural rainfall. The results showed that the crop yield and water use efficiency was increased significantly after 45 mm～90 mm supplementary irrigation, as compared with no irrigation. The optimum total amounts of supplementary irrigation for all three cropping patterns were 90 mm. The optimum amounts and periods of irrigation for mono-cultured wheat were 8mm before sowing and 82　mm at its boot stage, those for film-covered mono-cultured were 90mm at its big horn stage, and those for multipled cropping wheat and film-covered corn were 4mm before wheat sowing and 19　mm both at jointing and boot stages, and 24　mm both at jointing and big horn stages of corn. The results were suitable for northern upland fields.