稻田N_2O排放影响因素与减排研究进展

氧化亚氮(N_2O)是稻田生态系统中一种主要的温室气体,在全球温室效应中起着很大作用。本文从稻田N_2O的产生机制、影响稻田N_2O排放的主要因素以及稻田N_2O减排的技术措施等方面综述了稻田N_2O的研究进展,并对未来开展稻田N_2O排放研究提出了一些设想,以期为减少稻田温室气体排放和氮损失提供参考。     

辣木种子苗繁育技术操作规程

种苗繁育是规范化种植的基础环节，为进一步规范辣木种苗繁育技术，于2013～2015年对辣木种苗繁育过程中的种子采收、种苗繁育、田间管理、采收运输及分级标准进行了总结，并制定了辣木种苗繁育技术操作规程(SOP)，以期为辣木标准化的种苗生产提供依据。     

便携式XRF仪现场快速测定土壤中Pb的可行性研究

便携式XRF分析仪具有轻便、快速和可测对象较多与测量元素较广等特点而广泛应用于矿石、土壤等方面快速检测,但土壤的现场快速测定结果的准确性有待进一步研究与探讨。以安宁河谷平原土壤中Pb为研究对象,通过对便携式XRF仪现场快速检测结果与实验室分析结果的对比和影响因素的分析,建立基于安宁河谷平原表层土壤快速测定结果的线性函数为y=1.170 9x-17.326 0(R~2=0.992 9,x为现场检测结果),探讨其影响因素,为该区域表层土壤中Pb快速检测结果提供依据。     

脲酶抑制剂与硝化抑制剂对稻田土壤氮素转化的影响

【目的】本研究旨在阐明脲酶抑制剂(urease inhibitor,UI)和硝化抑制剂(nitrification inhibitor,NI)对稻田土壤氮素转化的影响,探讨抑制剂提高稻谷产量以及氮肥利用率的机理。【方法】本试验设在我国南方红壤稻田,共5个处理:1)不施氮肥(CK);2)尿素(U);3)尿素+脲酶抑制剂(U+UI);4)尿素+硝化抑制剂(U+NI);5)尿素+脲酶抑制剂+硝化抑制剂(U+UI+NI);脲酶抑制剂采用N-丁基硫代磷酰三胺(NBPT),硝化抑制剂采用3,4-二甲基吡唑磷酸盐(DMPP)。在水稻分蘖期和孕穗期测定土壤脲酶活性、硝酸还原酶活性、土壤铵态氮含量、硝态氮含量以及微生物碳、氮的含量,分析NBPT与DMPP对水稻两个主要生育期土壤氮素供应的影响,比较各处理的产量以及氮肥利用率,通过逐步回归分析研究以上各指标对产量的影响,探明脲酶抑制剂NBPT与硝化抑制剂DMPP在稻田的增效机理。【结果】1)与单施尿素相比,添加NBPT以及NBPT与DMPP配施均显著提高稻谷产量与地上部氮素回收率,两个处理分别增产6.56%与8.24%,氮素回收率提高幅度为19.4%与23.7%。2)与单施尿素相比,添加NBPT以及NBPT与DMPP配施,显著降低水稻分蘖期的土壤脲酶活性和铵态氮含量,显著提高孕穗期的铵态氮含量,而对此时期的脲酶活性无显著影响,所有处理对两个时期的硝态氮含量、硝酸还原酶活性、微生物量碳、氮含量均无显著影响;因此,NBPT对于抑制脲酶活性以及提高铵态氮含量的作用主要在孕穗期之前,而单施DMPP没有显著效应。3)从各项土壤指标与水稻产量相关性的逐步回归分析结果来看,水稻分蘖期与孕穗期稻田土壤中铵态氮含量对水稻产量影响显著,而且孕穗期的影响大于分蘖期,其余指标则对产量无显著影响。【结论】脲酶抑制剂NBPT以及NBPT与硝化抑制剂DMPP配施显著提高孕穗期土壤中的铵态氮含量,显著提高稻谷产量以及地上部氮素回收率,证明了生产上氮肥后移的重要意义。     

扬州市稻田高效种养模式应用现状及发展对策

近年来,扬州市根据国家农业供给侧结构性调整要求,充分利用自然资源禀赋,开展了多种形式稻田种养模式的示范与推广。本文阐述了扬州市稻鸭共作、稻虾共作以及稻田改作荷藕-虾共作等高效种养模式的应用现状,以单纯种稻为对照,比较了各种模式的生产效益;分析了稻田高效种养模式示范推广过程中存在的主要问题,并提出了促进稻田高效种养模式可持续发展的若干对策。     

发酵污泥不同施用方式对土壤温度和棉花苗期生理特性的影响

[目的]研究城市发酵污泥在棉花上的最佳施用方式,降低棉花生产成本。[方法]采用盆栽试验方法,探讨不施用发酵污泥(CK)、污泥覆盖土壤表面(处理(1))、污泥与土壤混合(处理(2))、混合+覆盖(处理(3))4种方式对棉苗、根系生长的影响。[结果]污泥的不同处理对棉花苗期根际土壤温度增温效果明显,以10 cm处土层最明显,处理(1)、(2)、(3)地温平均较对照CK高1.2、2.9、1.5℃;显著促进棉花苗的生长,棉花出苗率、健苗率、株高、叶面积、叶片数与CK相比极显著增加;对棉花苗根有诱导和促进生长作用,根长、根数量、根粗、根体积显著高于CK。[结论]发酵污泥3种不同施用方式都能够促进棉花苗生长,改善叶片和根的各项生理指标。整体来看,处理(2)综合优势好,是发酵污泥较有效的施用方式。     

杂交水稻种子不同活力测定方法与其田间成苗率的相关性

以3个杂交水稻品种不同活力水平的种子批为试验材料,比较了标准发芽试验、低温发芽测定和高温催芽试验3种活力测定方法,并将试验结果与田间成苗率进行相关性分析,发现标准发芽试验的发芽指标、低温发芽10 d的发芽率和高温催芽后的发芽率均与田间成苗率存在显著正相关关系,且高温催芽后的发芽率与田间成苗率相关系数最高。研究结果表明,高温催芽法可以作为杂交水稻种子活力测定的有效方法。     

金针菇菌渣有机肥对棉花产量及经济效益影响

以棉花为材料，在山东省德州市平原县前曹镇进行小区试验，试验共设菌渣有机肥作基肥、与化肥不同比例配施和农民习惯性施肥7个处理，研究施用金针菇菌渣有机肥对棉花产量及经济效益的影响。结果表明，菌渣有机肥可替代化肥在棉花上做基肥施用，可促进棉花增产，菌渣有机肥配合化肥使用效果较好，施用3000kg·hm-2菌渣有机肥和187．5kg·hm-2复合肥（15：15：15）的处理最佳，比农民习惯施肥增产8．2％，效益提高9．6％。     

The positive relationship between soil quality and crop production: A case study on the effect of farm compost application

In order to ensure sustainable agriculture, and for evaluating the effects of management practices on soil processes, tools for assessing soil quality are required. The development and use of a multiparameter index, which includes a wide range of soil properties, have been tested and found useful by several studies. However, soil quality measurements are ‘stand-alone’ tools unless they are either linked to important soil functions, used to characterize (agro)ecosystems or used to predict sustainability or productivity. In our study, the relationship between crop production and soil quality was assessed in a six year old field experiment studying the effect of farm compost (FC) amendment in a crop rotation of potato, fodder beet, forage maize and Brussels sprouts. To justify the hypothesis that repeated FC amendment results in both improved soil quality and consequently higher crop yields, a wide range of chemical, biological and physical soil properties were measured and integrated into a soil quality index (SQI). Next, crop yields were used as a functional goal to verify the causal relationship between SQI and crop production. Our results showed that there were significant changes in chemical, physical and biological soil quality as a result of repeated FC amendment. This was evidenced for example by a remarkable increase in both soil organic carbon (SOC) and total N content. Microbial biomass, the relative amount of bacterivorous nematodes and earthworm number were significantly increased as well and, together with SOC and total N, indicated as the dominant factors in assessing soil quality. The integration of these key indicators into the SQI revealed higher SQI values when FC was applied. In addition, crop yields were increased in all FC treated plots by which SOC was pointed out as the most important indicator influencing crop production. Finally, a causal relationship was observed between soil quality and the yield of potato and fodder beet. We conclude that our SQI may be a promising and useful tool to compare different (soil) management practices in relation to a strategic, regional goal, e.g., sustainable high yields. Before generalizing, we recommend a thorough validation of our SQI in other long-term field experiments.