不同耕作方式对旱作区冬小麦生产和产量的影响

为了筛选出适宜旱作区推广的耕作技术,在旱作大田条件下,设置一次深翻、免耕覆盖、深松覆盖、传统耕作四种耕作方式,研究了不同耕作方式下花后土壤水分和养分状况、小麦旗叶叶绿素含量、小麦旗叶净光合速率和小麦籽粒灌浆速率及产量。结果表明,免耕覆盖、深松覆盖开花期和灌浆期0～40 cm土层土壤水分含量分别比传统耕作提高了4.13%、6.23%和5.50%、9.27%,0～40 cm土层土壤碱解氮、速效磷和速效钾含量均显著高于传统耕作,为小麦开花后生长发育提供了良好的环境,从而提高了小麦灌浆中后期旗叶叶绿素含量和净光合速率,促进花后干物质积累及干物质向籽粒转运,进而提高了籽粒灌浆速率,使得籽粒产量显著提高。     

土壤改良剂节水增产效应的田间试验研究

采用田间试验,探讨了施用土壤改良剂对冬小麦的产量及水肥利用效率的影响.结果表明,施加土壤改良剂能降低作物生育期耗水量,提高冬小麦的产量,增加水肥利用效率.在不灌水条件下,施加土壤改良剂1 500 kg/hm~2,能够使冬小麦较对照增产15%,水分利用效率(WUE)提高了21.65%,磷肥利用效率(PUE)较单施磷肥增加2.92%.在灌水33.3 mm的条件下,施加土壤改良剂较对照可增产28.57%,将土壤改良剂与磷肥混施增产可达到42.86%.而且,PUE较单施磷肥增加了11.11%,WUE达到25.06kg/(hm~2·mm).     

Small-scale heterogeneity in carbon dioxide, nitrous oxide and methane production from aggregates of a cultivated sandy-loam soil

Spatial variability in carbon dioxide (CO₂), nitrous oxide (N₂O) and methane (CH₄) emissions from soil is related to the distribution of microsites where these gases are produced. Porous soil aggregates may possess aerobic and anaerobic microsites, depending on the water content of pores. The purpose of this study was to determine how production of CO₂, N₂O and CH₄ was affected by aggregate size and soil water content. An air-dry sandy loam soil was sieved to generate three aggregate fractions (<0.25 mm, 0.25–2 mm and 2–6 mm) and bulk soil (<2 mm). Aggregate fractions and bulk soil were moistened (60% water-filled pore space, WFPS) and pre-incubated to restore microbial activity, then gradually dried or moistened to 20%, 40%, 60% or 80% WFPS and incubated at 25 °C for 48 h. Soil respiration peaked at 40% WFPS, presumably because this was the optimum level for heterotrophic microorganisms, and at 80% WFPS, which corresponded to the peak N₂O production. More CO₂ was produced by microaggregates (<0.25 mm) than macroaggregate (>0.25 mm) fractions. Incubation of aggregate fractions and soil at 80% WFPS with acetylene (10 Pa and 10 kPa) and without acetylene showed that denitrification was responsible for 95% of N₂O production from microaggregates, while nitrification accounted for 97–99% of the N₂O produced by macroaggregates and bulk soil. This suggests that oxygen (O₂) diffusion into and around microaggregates was constrained, whereas macroaggregates remained aerobic at 80% WFPS. Methane consumption and production were measured in aggregates, reaching 1.1–6.4 ng CH₄–C kg⁻¹ soil h⁻¹ as aggregate fractions and soil became wetter. For the sandy-loam soil studied, we conclude that nitrification in aerobic microsites contributed importantly to total N₂O production, even when the soil water content permitted denitrification and CH₄ production in anaerobic microsites. The relevance of these findings to microbial processes controlling N₂O production at the field scale remains to be confirmed.     

Temporal variation of total and DTPA-extractable heavy metal contents as influenced by sewage sludge and perlite in a calcareous soil

Continuous application of sewage sludge (SS) as a source of organic matter, may increase available heavy metals (HMs) up to their critical levels. As a consequence their uptake by plants, risks of accumulation in food chain and groundwater pollution increases. To evaluate the effects of perlite and SS on total content and available fraction of iron (Fe), manganese (Mn), lead (Pb), copper (Cu), nickel (Ni), cadmium (Cd) and zinc (Zn) over 45 and 90 days a completely randomized pot experiment was conducted. Treatments consisted of SS (0, 2 and 4%) and combined SS and perlite levels (1:1, 1.5:0.5 and 0.5:1.5% SS:perlite). Mean available Fe, Ni, Cd, Mn and Zn fractions decreased over time by 7–27%, whereas, total contents did not change. Available HMs in SS-treated soils increased by 0.5–25%; whereas, only total Zn, Cu and Pb concentrations increased with SS application (although concentrations fall in the range of critical levels). The lowest (1.6 fold) and highest (22.1 fold) increases obtained for available Cu and Zn, respectively. Perlite could mitigate the adverse effect of high rate application of SS on amplification of HMs extractability. Therefore, their concomitant applications can be suggested considering the perlite durability and its positive effects on soil physical properties.     

中国粮食主产区参考作物蒸散量演变特征与成因分析

在全球变暖的背景下,参考作物蒸散量（reference crop evapotranspiration,ET0）的改变及其空间分布势必对中国粮食主产区农业水资源规划、农业用水管理等产生重要影响。本文将中国粮食主产区划分为温带湿润半湿润地区（I区）、温带干旱半干旱地区（II区）、暖温带半湿润地区（III区）和亚热带湿润地区（IV区）4个子区域,基于粮食主产区265个站点1961-2013年53a气象数据,采用FAO-56 Penman-Monteith公式计算各站点逐日ET0,利用ArcGIS空间插值、Mann-Kendall趋势检验、敏感性分析和贡献率分析等方法,对该区域ET0的时空分布规律及其成因进行分析。结果表明：（1）近53a来,中国粮食主产区年均ET0为878.9mm,整体呈显著下降趋势,速率为0.47mm·a^-1（P＜0.05）,I、II区和IV区年均ET0分别为741.8、1079.8和924.2mm且均有所减小,但变化趋势并不明显,III区年均ET0为940.2mm,呈极显著下降趋势,速率为1.21mm·a^-1（P＜0.01）。（2）全区及I-IV区ET0最敏感气象因子均为相对湿度,其敏感系数分别为-1.060、-1.232、-0.784、-1.114和-1.009。（3）全区及I-III区对ET0变化贡献最大的气象因子为风速,IV区为相对湿度。（4）风速的减小是造成粮食主产区全区及I-III区ET0减小的首要原因,风速减小和日照时数缩短是造成IV区ET0减小的主要原因。     

Irrigation and Zn fertilizer management improves Zn phyto‐availability in various rice production systems

Zinc (Zn) is an important micronutrient for rice (Oryza sativa L.) production and its deficiency has been observed in various production systems. High grain Zn concentration is equally important for high rice yield and human health. In this work, the effects of Zn fertilization on seedling growth, grain yield, grain Zn concentration, and their association with root traits were studied under alternate wetting and drying (AWD), aerobic rice (AR), system of rice intensification (SRI), and continuous flooding (CF). Zinc fertilization (15 kg ha^?1) improved nursery seedlings chlorophyll and Zn concentrations, root length, and number of roots with highest values observed in CF. At harvesting, maximum plant height, panicle length, total and panicle bearing tillers, and kernel yield were found with Zn addition in AWD and CF rice systems. Mid season drainage provided at maximum tillering and Zn fertilization increased its concentration in leaves, culms, panicles, and grains under CF and AR at physiological maturity. Most of Zn applied was allocated into culms and panicles, nevertheless, a significant increase in grain Zn concentration was also observed in all production systems. Association of leaf Zn with grain Zn concentration was stronger than with culm and panicle Zn. The results indicate that Zn application after rice nursery transplanting is more important for grain Zn enrichment in all rice systems than for increase in grain yield in all systems except AWD where grain yield was also increased. More grain yield in CF and AWD as compared to SRI and AR can also be attributed to decreased spikelet sterility and to better Zn phyto‐availability in these rice systems at physiological maturity.     

红外光谱技术在淀粉粒有序结构分析中的应用

傅里叶变换红外光谱技术(FTIR)可用于研究淀粉粒的有序结构,包括透射模式和衰减全反射模式2种。本文探讨不同去卷积设置条件对FTIR波谱的影响,并分析FTIR在淀粉粒有序结构分析中的应用。研究结果表明,不同去卷积设置对FTIR波谱和相关峰强度影响较大,以半峰宽19 cm^-1和增强因子1.9的设置对FTIR原始波谱去卷积,获得的结果较好。天然淀粉晶体类型不同,其FTIR波谱有差异,表现在马铃薯和山药淀粉的衰减全反射FTIR波谱相似,与水稻淀粉明显不同;水稻和马铃薯淀粉透射FTIR波谱相似,与山药淀粉明显不同。淀粉中的水分含量影响衰减全反射FTIR波谱,当水分含量超过60%时,对波谱分析结果基本没有影响。酸水解优先降解淀粉粒无定形区的结构成分,提高淀粉粒的有序度。淀粉葡糖苷酶水解淀粉对淀粉粒外部区域的有序度影响不大,但明显提高整个淀粉粒的有序度。不同品质稻米淀粉的衰减全反射FTIR波谱相似。上述研究结果为应用FTIR分析淀粉粒有序结构提供重要的参考作用。     

化肥施用对中国粮食产量的贡献率分析——基于主成分回归C-D生产函数模型的实证研究

施肥是农业持续发展的重要措施,施用化肥对中国粮食安全的保障作用是投入其他生产要素所不能替代的,掌握化肥的增产效应从指导农业生产及确定科学有效的施肥方案方面来说,都具有重要的理论与实践意义。分析了化肥施用量与粮食产量之间的关系,选取粮食作物播种面积、农用机械总动力、有效灌溉面积、化肥施用量和农业从业人员为中国粮食产量的影响因素,采用主成分回归C-D生产函数模型,计算了化肥投入对粮食增产的弹性及贡献率。结果表明：化肥施用与粮食产量之间存在较强的正相关关系;1978—2010年间化肥投入对粮食产量增长的弹性值为0.18,贡献率达20.79%,化肥对粮食增产的弹性和贡献与以往的研究结果相比略有下降,单位质量化肥投入带来的实际粮食产量增加量有所减少,但化肥投入仍是影响粮食产量增长的重要因素。     

储藏物冷却机在高温高湿区高大平房仓的应用

选用功率较小的储藏物冷却机与负压通风相结合,对福建漳州地区的粮面压盖稻谷仓进行降温冷却,通过改变粮面压盖方式实现冷却的均匀性和彻底性.累计运行时间112.7 h,降温3.3℃,水分变化为0.1％,达到了保水降温的效果.运行期间的降温单位能耗为0.47 kW·h/℃·t,符合《谷物冷却机低温储粮技术规程》的规定,结束降温后粮面压盖延缓了粮温复温.     

覆膜、沟垄作对旱作农田玉米产量和水分利用的叠加效应

为了揭示黄土高原半干旱区玉米(Zea mays L.)种植中覆膜、沟垄作的增产作用和水分利用特征, 布设大田定位试验, 包括全覆膜沟垄作、全覆膜平作、半覆膜平作和不覆膜平作4个处理。结果发现, 连续3个平水年中, 全膜沟垄作集成了全覆膜与沟垄作的优点, 产生明显的叠加效应, 较半膜平作分别增产2282.9、2460.2和2765.5 kg hm^-2, 增产率为32.3%、49.8%和46.5%。其中, 全覆膜的贡献分别为59.3%、90.3%和20.9%, 沟垄作的贡献分别为40.7%、9.7%和79.1%。叠加效应中全覆膜与沟垄作对产量的贡献呈此消彼长态势, 连作前两年, 全覆膜的作用大于沟垄作, 连作第3年, 沟垄作的作用大于全覆膜。玉米的水分利用效率, 全膜沟垄作较半膜平作的增幅为10.6%~25.2%。在同等降水条件下, 全覆膜沟垄作、全覆膜平作处理播前土壤贮水量较不覆膜平作增幅分别达6.3%~15.1%和3.5%~11.5%。收获期土壤贮水量明显低于不覆膜平作, 降幅达6.0%~12.9%和4.7%~7.5%。随着连作年限的增长, 土壤贮水量呈递减趋势, 连作第2、第3年收获期全覆膜沟垄作、全覆膜平作较连作开始土壤贮水量分别降低37.1%、44.0%和35.5%、40.9%, 连作第2年全覆膜沟垄作在50~200 cm出现干燥化现象, 第3年各处理30~200 cm土层均出现干燥化现象。综上所述, 全覆膜沟垄作具有明显的增产和提高水分利用效率的作用, 但其较高的产量以高耗水为代价, 在连续低降水条件下, 3年玉米连作会导致土壤干燥化, 存在生态安全风险。