新疆灌区农业节水发展现状与对策建议

水是新疆可持续发展的生命线,也是新疆农业发展的瓶颈。农业是新疆用水大户,占经济社会总用水量的90%以上,南疆农业用水占比更高。新疆节水潜力重点在农业,农业节水是新疆经济社会可持续发展的根本出路。为提高新疆农业水资源利用效率,促进农业高质量发展,本文梳理回顾了新疆灌区农业节水发展历程,分析了农业节水发展现状及存在问题,结合新时期国家对新疆农业发展的新定位、新要求,提出了大力发展适水型现代农业、加大高效节水工程建设、持续推进降盐节水、加强数字化灌区建设、加强农业节水宣传培训、健全农业节水服务体系等对策建议,以期为新疆现代农业可持续发展和保障国家粮棉油安全提供有力支撑。     

造纸废渣和养分的改良对北部硬阔叶林土壤表面CO_2通量的影响(英文)

安全经济地处理造纸废渣是林产品工业的一个主要考虑因素。本研究测定了造纸废渣和养分的改良对北部硬阔叶林土壤表面 CO2通量的影响,并量化该林分中 RS、土壤温度和湿度之间的关系。实验在美国 Michigan 州 Upper Peninsul地区糖槭(Acer saccharum Marsh)为主的硬阔叶林内采用完全随机区组设计进行三个处理:废渣改良施用、施肥和对照。RS 与土壤温度成正相关(R2 =0.80,p<0.001),而与土壤湿度相关很弱。土壤湿度仅在废渣改良施用处理中与 RS成正相关。废渣改良施用处理的 RS显著高于施肥(p = 0.033)和对照处理(p=0.048)的 RS。废渣改良施用处理中的最大 RS 为 8.8 μmol CO2·m-2·s-1,分别比施肥(4.6 μmol CO2·m-2·s-1)和对照处理3.9 (μmol CO2·m-2·s-1)中的最大 RS 高 91%和 126%。施肥和对照处理的 RS之间无显著性差异。废渣改良施用和其他处理的 RS之间的差异随处理时间而较少。表 4 图 3 参 33。     

The effects of alley cropping withLeucaena leucocephala and of different management practices on the productivity of maize and soil chemical properties in lowland coastal Kenya

The effects of leucaena hedgerows, mulching with leucaena foliage (0,50 and 100% of harvested foliage), cowpea intercropping and adition of dairy cattle slurry (55 t ha^–1 per maize crop) on the yield of maize from a sandy soil were assessed. The four-year results from five maize crops are reported.Except in the first year, yields of maize grain and stover were significantly reduced by 30% in the presence of leucaena hedgerows. Use of leucaena mulch eliminated this effect; application of all the harvested leucaena mulch (100%) increased the total maize grain yield of the five crops by 44% over sole maize. Hedgerow and mulching management required an additional 36 mandays labour ha^–1 which was more than compensated by the increased maize yields. Furthermore leucaena hedgerows substantially depressed the growth of weeds between cropping seasons.Intercropping with cowpea significantly depressed yields of maize grain and stover when both crops were sown together, but not in later seasons when cowpea was sown four weeks after the maize. Application of slurry increased the total yields of maize grain and stover by 35 and 37%, respectively. The grain yield of maize in leucaena hedgerow treatments fertilized with slurry did not respond to application of more than 50% of leucaena foliage, which suggested that half of the foliage could be spared for feeding to livestock. The cumulative yield of maize grain from the highest yielding organic system was 85% of the yield from the fertilizer treatment.The study, which is continuing, demonstrates that large increases in agricultural productivity are possible through the intercropping of maize with woody forage and grain legumes and the integration of dairy cattle production into the system. It thus shows the importance of exploiting crop/livestock interactions.     

膜下滴灌棉花高产群体质量诊断指标及优化调控途径

论述了膜下滴灌棉花高产群体质量诊断的主要指标及群体优化调控途径。描述膜下滴灌棉花高产群体质量的主要指标有 :高产群体光合速率与合理的叶面积指数发展动态、协调的群体干物质积累与分配、单位面积的总铃数和成铃率以及适宜 LAI条件下的铃叶比等。水、肥调控和化学调控技术对膜下滴灌棉花高产群体质量的建成具有十分重要的意义。     

地膜覆盖下土壤水分效应的模拟研究

通过分析地膜覆盖后土壤水分平衡的变化特点,建立了地膜覆盖前后农田土壤湿度变化的模拟方程.系统阐述了地膜覆盖土壤水分效应的形成机制及其变化规律.指出了地膜因子、气象因子及植物因子等在土壤水分效应形成中的作用,为地膜覆盖在农业生产中的优化利用提供了理论依据.     

Simulated Study on Effects of Ground Managements on Soil Water and Available Nutrients in Jujube Orchards

Soil erosion is a key factor affecting sustainable agriculture on Chinese Loess Plateau. A 2‐year study was conducted on jujube trees in a controlled study to compare effects of clean cultivation (CC) with jujube branch mulch (WJBM), strip white clover cover (SWC), strip shallow tillage (ST), jujube branch mulch under tree canopy + strip white clover cover (JBM + SWC) and jujube branch mulch under tree canopy + strip shallow tillage (JMB + ST). The study was on sloping soil (26·7%) in mesocosms (2·0 m × 0·8 m × 0·8 m) using a rainfall simulator. Runoff volume and sediment yield were significantly larger under CC than other treatments (p < 0·05), and were least under WJBM. Water infiltration under CC was significantly less than other treatments (p < 0·05), while it was the largest under WJBM. The available nitrogen (AN) and available phosphorus (AP) runoff loss under CC were significantly larger than others (p < 0·05), and least under WJBM. No differences in soil AN, AP and water‐soluble organic carbon (WSOC) concentrations were detected among all treatments. The soil AN and WSOC concentration under all treatments decreased during the growing season and slightly increased during fallow, while AP concentrations fluctuated but decreased slowly. The WJBM was the best management in this sloping jujube orchard study. Copyright © 2014 John Wiley & Sons, Ltd.     

设施菜地土壤酞酸酯污染的初步研究

通过对杭州周边某设施蔬菜大棚基地的土壤采集分析和农田残留农膜的提取分析,结果表明该地区土壤存在一定程度的酞酸酯污染,污染程度与国内大部分农田土壤相当。农膜中酞酸酯含量和农膜类型对土壤酞酸酯含量均有一定影响。农膜中酞酸酯含量和土壤中酞酸酯含量显著正相关,长期农膜覆盖与黑色农膜覆盖土壤的酞酸酯含量相对较高,因此减少农膜在土壤中的残留是减少土壤酞酸酯污染的有效途径之一。大棚覆盖或地膜覆盖等不同农膜覆盖方式对土壤酞酸酯含量在本研究中未发现显著差异。土壤酞酸酯含量与土壤有机质极显著正相关,表明土壤有机质对酞酸酯,尤其是高分子量酞酸酯污染单体的环境行为有重要的影响。     

浅松覆盖条件下二维根系吸水率模型

运用土壤水动力学方程反求根系吸水率,分析玉米拔节期梯形剖面取根资料,建立有效根密度分布函数,结合土壤剖面水分分布,建立适合浅松覆盖条件下的二维根系吸水率模型,并应用田间实测数据进行验证。结果表明,模拟值与实测值平均相对误差3.75%～7.11%,满足土壤水分动态模拟精度要求。     

塔克拉玛干沙漠公路防护林棵间土壤蒸发及蒸发量估算

通过田间试验,建立了实用性膜下滴灌棉花根系吸水模型,研究了在作物生长条件下的土壤水分运动,以揭示膜下滴灌棉花根系吸水规律。调查了不同生育期膜下滴灌棉花根系的分布,在棉花宽行及窄行采用根钻取样,将土样冲洗后,测定棉花根长参数,进而建立了棉花根长密度分布函数。根据理论分析和计算,考虑根长密度、土壤含水率及植株蒸腾量,建立了棉花根系一维吸水模型,其形式简单,涉及的参数较少。建立的棉花根系一维吸水模型能够反映棉花根系吸水的实际情况,应用方便,具有实际应用价值。     

不同剂量秸秆还田的保墒效果及其对玉米产量的影响

为了探讨在覆膜基础上不同剂量秸秆还田的保墒增产效果,在辽宁省朝阳市建平县的坡耕地上布设了田间小区试验;对未施入秸秆以及施入400,800,1200和1600kg/hm2共5种不同剂量处理秸秆还田的旱地农田土壤墒情及玉米产量进行了比较分析。结果表明,800kg/hm2处理的保墒效果优于其它各秸秆还田处理,400,800,1 200和1 600kg/hm2这4种不同剂量秸秆还田处理产量分别为5 069.20,5 781.46,5 462.25和5 407.46kg/hm2,较对照处理分别增产了18.62%,35.28%,27.81%和26.53%;800kg/hm2处理对玉米生长发育状况的影响优于其它剂量秸秆还田与未施入处理,差异均达极显著水平。