玉米地垄沟种平菇培肥地力的研究——Ⅰ.种菇方法和条件

本文筛选了培养材料和确定了粉碎的玉米芯培养基。该培养基组成:粉碎的玉米芯90％,麦麸8％,过磷酸钙1.5％,生石灰0.5％和0.2％的多菌灵含水达65—70％左右。将这个培养基制成一个堆,该堆高1.2—1.3m,宽1.5—1.7m,用塑料膜复盖,当堆中间达56℃以上时,翻堆3至4次每次间隔24～48小时。 当玉米秸杆能遮荫时(约7月5日),在玉米地垄沟栽培Pleurotus sapidus,通过实践证明在秋天可收获鲜菇10kg/m_2左右。     

玉米秸秆还田培肥土壤的效果

辽北地区玉米根茬还田、秸秆直接还田或间接还田的3年微区培肥试验研究结果表明,无机肥的增产效果特别明显,而施有机物料,更主要的作用是改善土壤的物理、化学性质、培肥地力,与无肥对照相比,有机无机肥料配合施用可使土壤有机质提高3．06％－27．78％,各有机物料对土壤有机质提高的顺序依次为100％秸秆＞50％秸秆＞土粪＞牛粪＞33％秸秆＞根茬。在含C量相等的条件下,秸秆对土壤有机质的保持和提高好于土粪,土粪好于牛粪。同时,与单施化肥比,有机无机肥料配合施用可使土壤易氧化有机质增加10．91％－20．67％,使浸提腐殖酸提高1．43％－14．28％,使结合态腐殖酸的松／紧比值提高0．07－0．19,HA／FA比值提高0．07－0．24,并且能改善土壤的N、P、K营养状况、土壤水分和土壤孔隙状况,这标志着土壤有机质活性的提高和土壤肥力状况的改善。因此,应该大力提倡玉米秸秆秋季直接还田,其最佳施入量应为当年生产量的30％－50％。     

有机与常规培肥模式生产水稻的碳足迹

为明确不同施肥模式对水稻生产碳足迹的影响,采取田间动态监测与室内分析相结合的方式,应用生命周期碳足迹的评价方法,研究了施用化肥(CF)、猪粪(ZM)、牛粪(NM)、鸡粪(JM)对稻田系统碳排放、碳增汇、水稻生产碳足迹及单位产量碳足迹的影响。结果表明:水稻种植过程中温室气体的排放是水稻生产碳排放的主要来源,与CF处理相比,施用有机肥可增加稻田碳排放,ZM、NM和JM处理分别增加34%、30%和65%,各处理均以稻田CO_2排放贡献最大;施用有机肥处理的环境正效应高于施用化肥处理,ZM、NM和JM处理碳增汇分别是CF处理的3.3、3.8和2.9倍,可相应抵消76%、92%和55%的碳排放;施用不同有机肥对水稻生产碳足迹影响不一,但与CF处理相比均可降低单位产量的碳足迹,ZM、NM和JM处理分别降低了55%、83%和22%。综合考虑畜禽粪污处理、肥料生产与管理以及水稻种植各环节的碳排放与稻谷产量情况,有机培肥有利于降低水稻单位产量碳足迹,其中以施用牛粪处理效果最佳。     

长期培肥黑土脲酶活性动态变化及其影响因素

以东北典型黑土区长期(自1980年)不同培肥试验地土壤为研究对象,采用两种不同量有机肥、化肥和不施肥4个处理,对土壤脲酶在作物生长季的动态变化进行研究。结果表明,施用有机肥,生长季黑土脲酶活性明显高于施用化肥和不施肥,其生长季脲酶保护容量在160mg·kg^-1·h^-1以上,季节性变化平稳。保持土壤脲酶免遭变性、免遭分解作用显著．脲酶活性的动态变化与绝大多数土壤生物、理化特性指标的动态变化没有明显的相关性;与土壤生物、理化特性,植物N、P、K有极显著的正相关关系;与土壤含水量、籽粒粗蛋白含量呈显著正相关关系。     

不同土壤培肥措施下农田有机物分解的生态过程

通过在河北曲周实验站的田间试验,研究了4种不同土壤培肥措施条件下农田生态系统中几种主要土壤生物随有机物分解的变化规律、有机物的分解及其主要影响因素。研究结果表明：除土壤线虫外,其他几种主要的土壤生物的分布规律基本上是堆肥区〉原貌区〉对照区〉化肥区,与施入的有机物（小麦秸秆）的分解规律一致。在受人为扰动的堆肥区、化肥区和对照区土壤中,细菌占绝对优势,而在未开垦的原貌区中,真菌起着重要作用。 在有机物分解初期,土壤微生物能比较快地迁移到秸秆表面,秸秆表面的生物数量最多的是细菌,随着细菌的数量增加,原生动物数量亦呈现增加趋势,蚯蚓数量增多,而线虫的数量则减少。而有机物分解后期,真菌的数量逐渐减少,蚯蚓的数量也呈下降趋势,有机物的分解速度减慢。通过灰色关联度分析,9种外界因素（生物因素和环境因素）对小麦秸秆分解作用的相对重要程度排序：土壤温度（0．844）〉蚯蚓（0．777）〉真菌（0．764）〉全氮（0．754）〉线虫（0．753）〉有机质（0．742）〉细菌（O．738）〉原生动物（0．693）〉土壤含水量（0．661）,其中土壤温度和蚯蚓是影响土壤有机物分解的最重要的两个因素。     

长期培肥黑土微生物量磷动态变化及影响因素

长期采用两种不同量有机肥(M2、M4)、化肥(NPK)方式培肥黑土,研究微生物量P在作物生长季动态变化．结果表明。施用有机肥微生物量P显著高于施用化肥(NPK)和不施肥(CK),微生物量P分别为M48．75～47．68mg·kg^-1,M2 3．02～37．16mg·kg^-1,NPK1．59～10．62mg·kg^-1,CK0．76～6．74mg·kg^-1之间,波动性较大．M4、M2处理微生物量P最大值出现在抽雄吐丝期,NPK、CK处理最大值出现在大喇叭口期;施肥数量和种类不同所引起的黑土微生物量P的差异并未因季节变化及玉米生育时期影响而明显改变．微生物量P的动态变化与绝大多数黑土生物、理化特性指标的动态变化没有显著的相关性;微生物量P与黑土生物、理化特性(除全钾外),植物氮、磷、钾含量有极显著的正相关关系,与黑土含水量呈显著正相关关系．     

长期培肥黑土微生物量碳动态变化及影响因素

以东北典型黑土区长期采用2种不同量有机肥(M2、M4)、化肥(NPK)和不施肥(CK)4种方式培肥土壤为研究对象,对生长季微生物量碳的动态变化进行研究．结果表明,施用有机肥,微生物量碳显著高于施用化肥和不施肥,容量在620mg·kg^-1以上．在各处理中。微生物量碳大小顺序为M4>M2>NPK≥CK．M2、M4微生物量碳最大峰值出现在抽雄吐丝期,NPK最大峰值出现在播种期,CK最大峰值出现在蜡熟期,季节性变化平稳．施肥数量和种类不同所引起的微生物量碳的差异,并未因季节变化及玉米生育时期影响而改变．微生物量碳的动态变化与绝大多数黑土生物、理化特性指标动态变化无显著相关性;与黑土生物、理化特性。植物氮、磷、钾及作物籽粒粗蛋白含量之间存在较好的正相关性．     

Outdoor cultivation of sea vegetables

Summary The outdoor cultivation of sea vegetables is carried out on a large scale in the Orient, mainly in Japan, China, Taiwan, Korea and the Philippines. Food crops are the most important among the sea vegetables cultivated, with Porphyra and Undaria being the more important in Japan and Laminaria in China. Eucheuma, an industrial crop containing the phycocolloid carrageenan, is cultivated in wide areas of the Philippines. The cultivation of the major food crops, which developed quickly over the past 30 years, is largely based on the results of research, especially with regard to seeding procedures, which have reached a certain level of sophistication.The major crops of sea vegetables are cultivated attached to ropes or nets located in a suitable site and habitat. Crops of limited economic value, however, are still cultivated by the old, primitive method of planting on stones on the ocean bed and other similar means. The location and timing of farming are selected with regard to the requirements of the plants for light, temperature, water movement, exposure to air (for the intertidal species),etc. Cultivation of seeding material of the three food crops and seeding of ropes and nets is carried out indoors under more or less controlled conditions. When the sporelings become established they are transferred to cultivation grounds in the ocean. When the plantlets grow too densely (in Laminaria) they have to be separated and replanted at the correct distances. This is done several weeks after transplantation to the ocean, when they are large and sufficiently strong. Eucheuma and other industrial crops are propagated vegetatively, using cuttings and fragments as planting material. Where seawater is lacking in nutrients, fertilizers are applied to guarantee a higher yield. The harvest is carried out manually, except for Porphyra, for which mechanical harvesters are used. Sea vegetables are attacked by pathogens that may cause severe damage to the crops. Diseases caused by improper growing conditions are also known. Grazers may also inflict losses. In all major crops the strains cultivated have been selected. In a few cases hybridization and other genetic techniques have been used to obtain domesticated varieties that can grow and yield far beyond the limits of their wild-type parents.Despite the fact that some mechanization has been introduced into the cultivation of sea vegetables, it is still by and large a highly labor-intensive enterprise. Nevertheless, it competes well with terrestrial crops in the Orient from the economic point of view.Interest in the cultivation of sea vegetables is widespread in the West and much experimental work aimed at its materialization has been underway during the lastca. twenty years.     

How can miscanthus fields be reintegrated into a crop rotation?

The bioeconomy, with its aim of replacing fossil by biobased resources, is increasingly focusing on biomass production from perennial crops, such as miscanthus. To date, research on miscanthus has explored a number of cultivation aspects; however, one major issue has not yet been addressed: How can former miscanthus fields be reintegrated into a crop rotation? This encompasses the questions of which following crop most efficiently suppresses resprouting miscanthus and what happens to the soil nitrogen content after a miscanthus removal. This study aimed to answer both questions. For this purpose, four spring crops (ryegrass, rapeseed, barley, maize) and fallow as control were cultivated after a Miscanthus sinensis removal. To test the effect of the removal on soil nitrogen content, each spring crop (excluding fallow) was divided into fertilized and unfertilized plots. After the spring crop harvest, winter wheat was cultivated to clarify which spring crop had most efficiently suppressed the resprouting miscanthus. The results indicate that fertilized crops had 35% less miscanthus biomass per hectare than unfertilized crops, probably due to the higher plant density and/or better development of the fertilized crops during the growing season. The soil mineral nitrogen (N_min) content was found to increase during the vegetation period following the miscanthus removal (average +14.85 kg/ha), but was generally on a low level. We conclude that nitrogen from miscanthus residues is partly fixed in organic matter and is thus not plant‐available in the first cropping season. As some nitrogen is supplied by the decomposition of miscanthus residues, our results suggest that the crop cultivated after a miscanthus removal requires less fertilization. Of all the follow‐on spring crops tested, maize coped with the prevailing soil conditions and resprouting miscanthus most efficiently, resulting in satisfactory yields, and thus seems to be a suitable crop for cultivation after miscanthus.     

NDVI曲线与农作物长势的时序互动规律

利用气象卫星NOAA AVHRR资料,反演出农作物生育期内每日和旬度的NDVI数据,分析了NDVI时间曲线的波动与农作物生长发育阶段及农作物长势的响应规律,并以华北冬小麦为例,探讨了NDVI在冬小麦中生育期的积分值与农作物单产之间的相互关系。结果表明,利用长时间序列的NDVI数据,结合作物的物候历,可以实现作物长势的遥感监测和产量遥感估算。     

Understanding and engineering beneficial plant–microbe interactions: plant growth promotion in energy crops

Plant production systems globally must be optimized to produce stable high yields from limited land under changing and variable climates. Demands for food, animal feed, and feedstocks for bioenergy and biorefining applications, are increasing with population growth, urbanization and affluence. Low‐input, sustainable, alternatives to petrochemical‐derived fertilizers and pesticides are required to reduce input costs and maintain or increase yields, with potential biological solutions having an important role to play. In contrast to crops that have been bred for food, many bioenergy crops are largely undomesticated, and so there is an opportunity to harness beneficial plant–microbe relationships which may have been inadvertently lost through intensive crop breeding. Plant–microbe interactions span a wide range of relationships in which one or both of the organisms may have a beneficial, neutral or negative effect on the other partner. A relatively small number of beneficial plant–microbe interactions are well understood and already exploited; however, others remain understudied and represent an untapped reservoir for optimizing plant production. There may be near‐term applications for bacterial strains as microbial biopesticides and biofertilizers to increase biomass yield from energy crops grown on land unsuitable for food production. Longer term aims involve the design of synthetic genetic circuits within and between the host and microbes to optimize plant production. A highly exciting prospect is that endosymbionts comprise a unique resource of reduced complexity microbial genomes with adaptive traits of great interest for a wide variety of applications.     

Long-term global trends in crop yield and production reveal no current pollination shortage but increasing pollinator dependency

There is evidence that pollinators are declining as a result of local and global environmental degradation [1-4]. Because a sizable proportion of the human diet depends directly or indirectly on animal pollination [5], the issue of how decreases in pollinator stocks could affect global crop production is of paramount importance [6-8]. Using the extensive FAO data set [9], we compared 45 year series (1961-2006) in yield, and total production and cultivated area of pollinator-dependent and nondependent crops [5]. We investigated temporal trends separately for the developed and developing world because differences in agricultural intensification, and socioeconomic and environmental conditions might affect yield and pollinators [10-13]. Since 1961, crop yield (Mt/ha) has increased consistently at average annual growth rates of approximately 1.5%. Temporal trends were similar between pollinator-dependent and nondependent crops in both the developed and developing world, thus not supporting the view that pollinator shortages are affecting crop yield at the global scale. We further report, however, that agriculture has become more pollinator dependent because of a disproportionate increase in the area cultivated with pollinator-dependent crops. If the trend toward favoring cultivation of pollinator-dependent crops continues, the need for the service provided by declining pollinators will greatly increase in the near future.     

Insect pollinated crops, insect pollinators and US agriculture: trend analysis of aggregate data for the period 1992-2009

In the US, the cultivated area (hectares) and production (tonnes) of crops that require or benefit from insect pollination (directly dependent crops: apples, almonds, blueberries, cucurbits, etc.) increased from 1992, the first year in this study, through 1999 and continued near those levels through 2009; aggregate yield (tonnes/hectare) remained unchanged. The value of directly dependent crops attributed to all insect pollination (2009 USD) decreased from $14.29 billion in 1996, the first year for value data in this study, to $10.69 billion in 2001, but increased thereafter, reaching $15.12 billion by 2009. The values attributed to honey bees and non-Apis pollinators followed similar patterns, reaching $11.68 billion and $3.44 billion, respectively, by 2009. The cultivated area of crops grown from seeds resulting from insect pollination (indirectly dependent crops: legume hays, carrots, onions, etc.) was stable from 1992 through 1999, but has since declined. Production of those crops also declined, albeit not as rapidly as the decline in cultivated area; this asymmetry was due to increases in aggregate yield. The value of indirectly dependent crops attributed to insect pollination declined from $15.45 billion in 1996 to $12.00 billion in 2004, but has since trended upward. The value of indirectly dependent crops attributed to honey bees and non-Apis pollinators, exclusive of alfalfa leafcutter bees, has declined since 1996 to $5.39 billion and $1.15 billion, respectively in 2009. The value of alfalfa hay attributed to alfalfa leafcutter bees ranged between $4.99 and $7.04 billion. Trend analysis demonstrates that US producers have a continued and significant need for insect pollinators and that a diminution in managed or wild pollinator populations could seriously threaten the continued production of insect pollinated crops and crops grown from seeds resulting from insect pollination.     

Salt Tolerance in Selected Vegetable Crops

Ensuring adequate food production is a major issue in the context of an increasing human population, limit to the areas of new land that can be cultivated, and loss of existing cultivated lands to abiotic stresses. Of these stresses, salinity consistently has the greatest impact in reducing the area of cultivated land, often due to inappropriate irrigation techniques. To increase food supply, there is a need to produce salt-tolerant crops, which can grow successfully on salt-affected lands. Among crops, vegetables possess a central position in the human diet because of their nutritional value providing vitamins, carbohydrates, proteins, and mineral nutrients. There are many vegetable crops of local importance around the world but others that are very widely cultivated. All of these vegetable crops are affected by salinity more or less severely. Salinity affects every aspect of vegetable crop development including their morphology, physiological function and yield. Although efforts have been made to understand the mechanisms of salt tolerance in vegetable crops, less attention has been paid to these than to the staple crops. Where attempts have been made to improve salt tolerance of vegetables, the strategies have ranged from exogenous application of fertilizers, compatible solutes or plant growth regulators, to use of advanced molecular techniques for genetic modifications. This review focuses on the responses of pea, okra, tomato, eggplant, pepper, carrot, broccoli, cauliflower, and potato to salt stress and the strategies being used to enhance their salt tolerance.     

Genetic variation and possible origins of weedy rice found in California

Control of weeds in cultivated crops is a pivotal component in successful crop production allowing higher yield and higher quality. In rice‐growing regions worldwide, weedy rice (Oryza sativa f. spontanea Rosh.) is a weed related to cultivated rice which infests rice fields. With populations across the globe evolving a suite of phenotypic traits characteristic of weeds and of cultivated rice, varying hypotheses exist on the origin of weedy rice. Here, we investigated the genetic diversity and possible origin of weedy rice in California using 98 simple sequence repeat (SSR) markers and an Rc gene‐specific marker. By employing phylogenetic clustering analysis, we show that four to five genetically distinct biotypes of weedy rice exist in California. Analysis of population structure and genetic distance among individuals reveals diverse evolutionary origins of California weedy rice biotypes, with ancestry derived from indica, aus, and japonica cultivated rice as well as possible contributions from weedy rice from the southern United States and wild rice. Because this diverse parentage primarily consists of weedy, wild, and cultivated rice not found in California, most existing weedy rice biotypes likely originated outside California.     

北方农牧交错区农业生态系统生产力对气候波动的响应——以准格尔旗为例

气候变化对区域生态系统结构和功能有重大影响。以中国北方农牧交错区的准格尔旗为例,利用气象和《统计年鉴》数据,采用数理统计方法分析准格尔旗1961—2009年降水量、平均气温的波动特征,计算出该地区1961—2009年农业生态系统NPP值和主要农作物的气候产量,论述了准格尔旗农业生态系统生产力对气候波动的响应。结果表明:(1)降水量和平均气温的年际、年内波动均显著。(2)准格尔旗农业生态系统生产力呈现阶段性地波动上升趋势。排除社会、科技等影响,气候生产力对气候波动表现出较强的敏感性,是作物气候生态适应的结果。(3)中国北方雨养旱作区,粮食气候产量受降水量年际波动(特别是7、8月)显著影响;谷子、糜黍、玉米、薯类、大豆和油料等农作物的气候产量与降水量年际波动呈显著正相关;谷子、糜黍的气候产量与生长季降水量年内波动呈显著负相关。集水型生态农业是北方农牧交错区生态环境友好的农业发展模式。(4)谷子、糜黍、薯类、大豆和油料等农作物的气候产量与6、7、8月平均气温年际波动呈显著负相关;生长季平均气温年内波动对谷子、糜黍、大豆和油料等农作物的气候产量有显著负面影响。因此,需要综合采取工程、生物和农业措施,将气候变化对主要农作物气候产量的不利影响降到最低。     

Global climate change increases risk of crop yield losses and food insecurity in the tropical Andes

One of the greatest current challenges to human society is ensuring adequate food production and security for a rapidly growing population under changing climatic conditions. Climate change, and specifically rising temperatures, will alter the suitability of areas for specific crops and cultivation systems. In order to maintain yields, farmers may be forced to change cultivation practices, the timing of cultivation, or even the type of crops grown. Alternatively, farmers can change the location where crops are cultivated (e.g., to higher elevations) to track suitable climates (in which case the plants will have to grow in different soils), as cultivated plants will otherwise have to tolerate warmer temperatures and possibly face novel enemies. We simulated these two last possible scenarios (for temperature increases of 1.3°C and 2.6°C) in the Peruvian Andes through a field experiment in which several traditionally grown varieties of potato and maize were planted at different elevations (and thus temperatures) using either the local soil or soil translocated from higher elevations. Maize production declined by 21%–29% in response to new soil conditions. The production of maize and potatoes declined by >87% when plants were grown under warmer temperatures, mainly as a result of the greater incidence of novel pests. Crop quality and value also declined under simulated migration and warming scenarios. We estimated that local farmers may experience severe economic losses of up to 2,300 USOne of the greatest current challenges to human society is ensuring adequate food production and security for a rapidly growing population under changing climatic conditions. Climate change, and specifically rising temperatures, will alter the suitability of areas for specific crops and cultivation systems. In order to maintain yields, farmers may be forced to change cultivation practices, the timing of cultivation, or even the type of crops grown. Alternatively, farmers can change the location where crops are cultivated (e.g., to higher elevations) to track suitable climates (in which case the plants will have to grow in different soils), as cultivated plants will otherwise have to tolerate warmer temperatures and possibly face novel enemies. We simulated these two last possible scenarios (for temperature increases of 1.3°C and 2.6°C) in the Peruvian Andes through a field experiment in which several traditionally grown varieties of potato and maize were planted at different elevations (and thus temperatures) using either the local soil or soil translocated from higher elevations. Maize production declined by 21%–29% in response to new soil conditions. The production of maize and potatoes declined by >87% when plants were grown under warmer temperatures, mainly as a result of the greater incidence of novel pests. Crop quality and value also declined under simulated migration and warming scenarios. We estimated that local farmers may experience severe economic losses of up to 2,300 US$ ha^?1 yr^?1. These findings reveal that climate change is a real and imminent threat to agriculture and that there is a pressing need to develop effective management strategies to reduce yield losses and prevent food insecurity. Importantly, such strategies should take into account the influences of non‐climatic and/or biotic factors (e.g., novel pests) on plant development.