芹菜露地反季节高产栽培技术

芹菜性喜冷凉湿润的环境条件,害怕高温干旱,不耐霜冻。中原地区露地常规栽培的芹菜一年种两茬。一茬在5月上旬育苗,8月上旬定植,11月上旬上市;另一茬在8月下旬育苗,11月中旬定植,第二年4月底5月初上市。这两茬     

大棚菠菜—番茄—芹菜一年三茬高效栽培模式

塑料大棚菠菜-番茄-芹菜连作栽培模式具体茬口如下：第1茬菠菜于11月上旬播种,翌年4月上旬收获;第2茬番茄于2月上旬育苗,4月10日定植,6月上旬上市,7月底拉秧;第3茬芹菜于6月初育苗,8月初定植,10月下旬收获。经过数年的栽培实践,该栽培模式均获得了较好的经济效益。现将相关栽培技术作一介绍。     

大棚菠菜-番茄-芹菜一年三茬高效栽培模式

塑料大棚菠菜-番茄-芹菜连作栽培模式具体茬口如下:第1茬菠菜于11月上旬播种,翌年4月上旬收获;第2茬番茄于2月上旬育苗,4月10日定植,6月上旬上市,7月底拉秧;第3茬芹菜于6月初育苗,8月初定植,10月下旬收获.经过数年的栽培实践,该栽培模式均获得了较好的经济效益.现将相关栽培技术作一介绍.     

大拱棚马铃薯—芹菜一年两茬栽培技术

宁夏西吉地区采用大拱棚马铃薯-芹菜一年两茬栽培模式,每667m平均生产马铃薯2000kg、芹菜5000kg,产值共计近1万元,经济效益显著.其中,马铃薯于3月初播种,6月中旬上市；移栽芹菜于5月进行露地育苗,7月中下旬定植,10月底至11月初采收上市.     

拱棚春茬西瓜-秋延辣椒连作高产栽培模式

拱棚春茬西瓜一秋延辣椒连作模式,在陕西蒲城地区推广面积大,具有较好的经济效益.西瓜1月上中旬育苗,2月下旬至3月上旬定植,5月中下旬开始采收上市;辣椒7月上旬进行育苗,7月底、8月初定植,11月上旬陆续收获上市销售.     

无公害菜豆温室生产实用技术

<正>1茬口安排与品种选择适宜温室栽培的茬口有冬春茬和秋冬茬两个茬次。冬春茬:12月下旬温室育苗,次年1月下旬定植,3~5月份采收上市。适宜的品种有双丰架豆、绿龙、架豆王等。秋冬茬:8月中旬露地小拱棚育苗,9月上旬定植,10月~12月采收上市。适宜的品种有秋紫豆、双丰架豆等。     

甘蓝露地一年两茬高效栽培

通过提前育苗、地膜覆盖等技术措施，露地甘蓝可实现一年两茬高效栽培，产量高，效益好。春甘蓝2月下旬采用小拱棚育苗，3月下旬整地、趁墒覆膜，4月上旬定植，6月中旬上市；秋甘蓝6月中旬育苗，7月中旬定植，9月上旬上市，10月中旬收完。     

拱棚春茬西瓜—秋延辣椒连作高产栽培模式

拱棚春茬西瓜一秋延辣椒连作模式,在陕西蒲城地区推广面积大,具有较好的经济效益。西瓜1月上中旬育苗,2月下旬至3月上句定植,5月中下旬开始采收上市;辣椒7月上旬进行育苗,7月底、8月初定植,11月上旬陆续收获上市销售。     

日光温室越冬黄瓜——夏秋丝瓜——芹菜育苗高效栽培技术

1、茬口安排 冬茬黄瓜。10月上中旬播种育苗，11月上中旬定植，12月上中旬至来年5月收获。夏秋茬丝瓜。4月下旬至5月上旬，即前茬拉秧前35天左右直播或育苗、定植，夏秋季生产。秋冬茬芹菜育苗播期为6月中旬-7月中旬，苗龄50-60天。     

蔬菜一年三茬高效栽培模式

近年来,湖南省衡阳县樟木乡高程村一带的农户在生产实践中摸索出了芹菜-空心菜-苦瓜一年三茬高效栽培模式,每亩生产总值在18 000元以上。现将该生产模式技术要点总结如下。1茬次安排芹菜在8月上旬播种,8月底至9月初定植,春节前开始收获上市,来年3月中旬收获完毕。苦瓜2月底至3月初在大田内搭建小拱棚采用营养钵育苗,3月底至4月初定植,搭平棚栽培,5月初上市。     

有效营造城市特色景观研究

在经济全球化和信息高度发达的今天,城市文化出现多元化的现象,导致全球范围内的文化"趋同",各种设计形式和手法简单的如同潮流般被模仿.现从城市景观的基础理论入手,分析建设有城市特色景观的重要性和意义.在借鉴国外的理论研究和实践经验的基础上,探索营造城市特色景观的有效方法和途径.     

堤滩刺槐林改建栽培油桃

1998年从山东省果树引进超五月火油桃，利用砍伐刺槐后的堤滩地栽培，经3年管理，平均666.7m^2产油桃1602.4kg，经济效益显著。     

Computation of the Boltzmann entropy of a landscape: a review and a generalization

Landscape Ecology - A key goal of landscape ecology is to understand landscape ecological processes across space and through time, with reference to the central organizing principles of nature....     

Light studies in a spacing trial with apple on a dwarfing and a semi-dwarfing rootstock

Light interception by the orchard canopies in a spacing trial with Golden Delicious and Jonathan on M IX and on M II was measured in 1968, 1969 and 1970. In 1969 and 1970 light distribution over the Golden Delicious hedges in the high-density plots was also measured and related to fruit and foliage distribution and to fruit quality. Simultaneously, integrated light readings at 100–200 locations were taken over 24-hour periods, using a photochemical method.Although all plots attained their ceiling yield level in 1967, the 6th year after planting, light interception continued to increase from 1968 to 1970. In the low-density plots — 1100 trees per ha on M IX and 660 trees per ha on M II — the canopies intercepted roughly half of the incident light and yields levelled off at 40 tons per ha. The high-density M IX plot (3300 trees per ha) intercepted two-thirds, the high-density M II plot (2260 trees per ha) more than three-quarters of incident light. Both plots yielded more than 70 tons per ha in 1967 and 1968, but thereafter the yield level dropped, especially for trees on M II, presumably because of mounting inter-tree competition for light.Light levels in the hedges in the high-density plots at equal distances from the hedge perimeter were very much the same for both varieties, for both rootstocks and in the two years. Light levels fell sharply towards the interior and bottom parts of the hedges. The main advantage of the M IX hedge was its smaller cross section, leaving little room for a poorly illuminated centre. At lower light levels weight per fruit and especially fruit colour declined, but the relation between light level and fruit quality was not consistent for both rootstocks and in both years. These inconsistencies could be explained on the basis of differences in pruning system, affecting the type of wood on which the fruit is borne.Fruit was concentrated in the interior part of the hedges, so that a high proportion of the crop suffered from the poor light conditions in this part. Fruit distribution was generally correlated with foliage distribution. In the M IX hedge by far the highest leaf density was found in the centre of the hedge. This is an advantage in comparison with the large leaf area — relatively unproductive and casting much shade — in the top of the M II hedge. Light measurements before and after fruit removal suggested that the shade cast by the fruit is negligible as compared to shading by the foliage.It is concluded that canopy architecture in the high-density M IX plot, with a leaf area index of 2.15, is close to the optimum for single row planting systems in Northwest Europe. Gains in percentage light interception, as in the high-density M II plot, are associated with a greatly inferior light distribution over the canopy, leading to lower yields per unit growth and deterioration of fruit quality. In addition to light, pruning strongly influences fruit quality.     

The distribution of a threatened migratory bird species in a patchy landscape: a multi-scale analysis

Understanding the driving forces behind the distribution of threatened species is critical to set priorities for conservation measures and spatial planning. We examined the distribution of a globally threatened bird, the corncrake (Crex crex), in the lowland floodplains of the Rhine River, which provide an important breeding habitat for the species. We related corncrake distribution to landscape characteristics (area, shape, texture, diversity) at three spatial scales: distinct floodplain units (“floodplain scale”), circular zones around individual observations (“home range scale”), and individual patches (“patch scale”) using logistic regression. Potential intrinsic spatial patterns in the corncrake data were accounted for by including geographic coordinates and an autocovariate as predictors in the regression analysis. The autocovariate was the most important predictor of corncrake occurrence, probably reflecting the strong conspecific attraction that is characteristic of the species. Significant landscape predictors mainly pertained to area characteristics at the patch scale and the home range scale; the probability of corncrake occurrence increased with potential habitat area, patch area, and nature reserve area. The median potential habitat patch size associated with corncrake occurrence was 11.3 ha; 90% of the corncrake records were associated with patches at least 2.2 ha in size. These results indicate that the corncrake is an area-sensitive species, possibly governed by the males’ tendency to reside near other males while maintaining distinct territories. Our results imply that corncrake habitat conservation schemes should focus on the preservation of sufficient potential habitat area and that existing management measures, like delayed mowing, should be implemented in relatively large, preferably contiguous areas.     

果实乃日中储水库:一个长期争议的问题(英文)

20世纪初创立的所谓"果实乃日中储水库"的理论,在70—80年代受到了挑战。反对者认为原来理论创立者所采用的是切枝试材而非完整植株,属于试验方法上的错误。他们怀疑切枝试材会迫使形成一种非自然的水势梯度,导致蒸腾的叶片能够从果实获取水分。本文报道氚水示踪法在完整植株上的试验结果,证明果实的水分完全可以被叶片抽走,此外,"去果实"和"留果实"的对比试验证明果实的存在有利于降低叶片在昼间的缺水程度,即叶水势相对较高。作者指出果实在夜间对水分的竞争力往往超过叶片,所以结果多的果树植株反而容易受旱而死。因此,单纯把果实比喻为"储水库",作为科学用语似不恰当。     

Estimating density of a territorial species in a dynamic landscape

Context

Conservation planning for at-risk species requires understanding of where species are likely to occur, how many individuals are likely to be supported on a given landscape, and the ability to monitor those changes through time.

Objectives

We developed a distribution model for northern spotted owls that incorporates both habitat suitability and probability of territory occupancy while accounting for interspecies competition.

Methods

We developed range-wide habitat suitability maps for two time periods (1993 and 2012) for northern spotted owls that accounted for regional differences in habitat use and home range size. We used these maps for a long-term demographic monitoring study area to assess habitat change and estimate the number of potential territories based on available habitat for both time periods. We adjusted the number of potential territories using known occupancy rates to estimate owl densities for both time periods. We evaluated our range-wide habitat suitability model using independent survey data.

Results

Our range-wide habitat maps predicted areas suitable for territorial spotted owl presence well. On the demographic study area, the amount of habitat declined 19.7% between 1993 and 2012, while our estimate of the habitat-based carrying capacity declined from 150 to 146 territories. Estimated number of occupied territories declined from 94 to 57.

Conclusions

Conservation and recovery of at-risk species depends on understanding how habitat changes over time in response to factors such as wildfire, climate change, biological invasions, and interspecies competition, and how these changes influence species distribution. We demonstrate a model-based approach that provides an effective planning tool.

     

Behavior as a tool for assessing a managed landscape: a case study of the Karner blue butterfly

In an increasingly human-dominated landscape, effective management of disturbance-maintained ecosystems, such as grasslands and savannas, is critical to the conservation of biodiversity. Yet, the response of individual organisms to landscapes created by disturbances and management is rarely studied. In this study, we examined the endangered Karner blue butterfly, Lycaeides melissa samuelis, in a heterogeneous oak savanna. Our objective was to quantify the butterfly’s habitat use and behavior to assess the effects of prescribed burning. The oak savanna management in Ohio, USA divides each Karner blue site (n = 4) into three units. Each one-third unit is then burned, mowed, or unmanaged in an annual rotation within each site, and the result is a fire return interval of ~3 years. Our surveys measured habitat use, while behavior observations quantified reproduction and foraging for the two annual broods. Our habitat use results showed burned treatments were recolonized quickly, but there was not a clear selection for burned treatments. Foraging rates were similar in all treatments; however, females oviposited significantly less in unmanaged treatments (only 5 of 127 ovipositions). This oviposition preference was likely due to habitat degradation and the availability of recently burned, early successional habitat. Since Karner blues avoided reproduction in units unburned for ≥4 years, these units could be burned to create high quality early successional habitat. These results demonstrate how behavioral decisions can be pivotal forces driving spatial population dynamics. Our case study demonstrates how a fine-scale landscape perspective combined with measurements of behavioral processes can assist with management decision-making.