巴西蘑菇培养料筛选

对11个配方进行试验,筛选出一种适合巴西蘑菇生长的高产培养料配方:棉籽壳42％,麦草28％,牛粪20％,麦轶5％,石灰2.5％,过磷酸钙1％,石膏1％,尿素0.5％。用这种培养料栽培巴西蘑菇,产量可达到9.12～9.59 kg·m~(-2),生物学效率为39.65％～41.70％。     

稀土对刺槐苗木生理特性影响的研究

稀土对刺槐苗木生理特性影响的研究赵兰勇，梁玉堂（山东农业大学林学院泰安２７１０１８）王九龄（北京林业大学北京１０００８３）关键词稀土，刺槐，光合速率，叶绿素含量，水分利用效率，矿质元素含量近年来，稀土元素在农业上的应用研究越来越受到人们的重视，并且已...     

棉花调亏灌溉的生理基础研究

以盆栽棉花为材料,通过苗期和现蕾期不同程度的亏水处理(低、中、高三个水平),对调亏灌溉节水效应及生理机制进行了研究。结果表明:适时适度的水分亏缺可使植株旺盛的营养生长得以有效控制,株型和根冠比都更为理想。调亏期间,蒸腾速率和气孔导度都明显下降,而光合速率下降不明显,复水后光合速率和气孔导度明显恢复且接近或高于对照;此外,水分亏缺不仅影响棉桃的数量,而且影响单果重。表明适度的亏水处理可使水分利用效率明显提高,而经济产量接近或高于对照,同时节水20%以上。     

限水灌溉对转基因抗虫棉产量形成的影响

采取限水灌溉的方法,研究了灌水对棉花产量形成的影响。研究结果表明,合理灌水能促进棉花开花成铃,延长最佳成铃时段,增加棉株优质节位的成铃数,单株籽棉干物重增加23.4%～61.9%,产量提高16.8%～45.3%。灌水量以675m3/hm2效果最好,灌水效益高达0.57kg/m3,灌水量达1350m3/hm2增产幅度下降,灌水效益仅0.21kg/m3。     

退耕还草产业化技术经济效果评价方法探讨

以平凉市退耕还草产业化技术开发为例,以产业化系统链中各子系统间的功能协调统一为依据,以退耕还草产业化机制为纽带,在研究建立平凉市退耕还草产业化技术经济效果包括4个一级指标(基础指标、配套指标、服务指标和效益指标)和17个二级指标体系的基础上,采用层次分析法(AHP法)、隶属度函数法和综合效益指数法作为退耕还草产业化技术经济效果的评价方法.经比较得出:平凉市退耕还草产业化技术开发综合指数达到0.595 1,属初步产业化阶段,相对发展指数达到27.268%,年均产业化进步速度达到6.817%.     

海河平原区棉花饲用黑麦复种方式及水肥利用效率分析

2011年10月-2014年10月连续3年在河北省任县安排了定位试验,通过饲用黑麦不同播期与棉花构建几种棉草复种茬口搭配方式,从产量、经济效益、水分利用效率和养分利用效率以及对土壤肥力影响等方面综合分析棉花饲用黑麦复种的可行性及复种方式。结果表明,棉花可与饲用黑麦复种,为降低饲用黑麦对棉花的影响,饲用黑麦可适当推迟到10月20日播种,次年4月底收获,效益可提高5470.1元·hm^-2。棉花饲用黑麦复种与棉花单作相比,平均水分利用率提高16.49%;水分经济利用效率提高56.54%;并且土壤有机质平均增长幅度提高5.71%,土壤含盐量平均降低幅度达到23.72%,土壤改良效果明显;是适用于该区域的高效复种模式。     

Innovative layer genetics to handle global challenges in egg production

1. In commercial layer breeding, extensive gene pools are tested and selected for market requirements which must be anticipated at least 5 years ahead. Field results confirm a continuous positive genetic trend in egg output and better feed efficiency which can be converted into land savings.

2. Animal welfare and cage-free housing dominate future needs of the market. Nesting behaviour and minimal tendency to develop feather-pecking or cannibalism without beak treatment are key trait complexes. Stronger shells for longer production cycles without moulting have to be combined with better bones.

3. No single big gene effect can be expected to control the multifactorial problem of feather-pecking. Adjusting the shape of the beak, with a heritability of .10–.25, can contribute to reducing the risk of severe cannibalism.

4. For better skeletal integrity, the assessment of bone quality in pedigree birds housed in enriched cages is done by keel bone palpation or ultrasound measurement of the humerus. Both traits show similar heritabilities in the range of .15–.30 and can be included in a balanced selection approach for performance, quality and welfare traits.

5. The combination of performance testing and genome-wide DNA marker analysis is a promising tool to generate more progress for a balanced performance and behaviour profile.     

Sex‐dependent responses of perch to changes in water clarity and temperature

Rising temperatures and decreasing water transparency of lakes have strong wide ranging effects on fish. Fish responses to various changes in the environment are usually species‐dependent, but responses may also vary within species. In general, large individuals are considered to be more sensitive to environmental variation due to higher energy demand, than smaller individuals. Similarly, large individuals require more food to maintain bodily functions and are thus more sensitive to resource and food scarcity. These size‐specific responses to environmental gradients are also sex‐dependent in species that exhibit sexual size dimorphism (SSD). We studied in enclosures with short‐term experiments how rising temperatures and decreasing water transparency regulate the feeding rates of female and male European perch (Perca fluviatilis L.). To explore experimental results, we calculated perch SSD in nine lakes with varying environmental conditions using previously collected field data. The results of the experiments revealed that the combined effect of water transparency and temperature on the feeding rate of fish is gender‐dependent: feeding rate of females decreased more than that of males. The experimental results were also supported by field data that revealed a negative relation between water transparency and the magnitude of SSD in perch. Our results suggest that rising temperatures and decreasing water transparency may potentially decrease fish size in a sex‐dependent manner. As female size is one of the main demographic traits determining the reproductive success of a fish population, changing environments may have unexpected and far‐reaching consequences on fish population dynamics.     

种植密度对滴灌马铃薯生长、产量的影响

为了了解耕培土滴灌条件下种植密度对马铃薯生长、产量以及水分利用效率的影响.试验共设密度分别为7.28×10⁴ 株/hm²(RS25),6.67×10⁴ 株/hm²(RS35),5.55×10⁴ 株/hm²(CK)3个处理.结果表明:随着种植密度的增加,株高、茎粗、干物质积累量以及商品薯率均有降低的趋势;产量、水分利用效率随种植密度的增加表现出先增大后减少,其中RS35处理产量和水分利用效率均表现最高,分别达到47 325 kg/hm²和12.05 kg/m³;在马铃薯品质方面,种植密度对马铃薯粗蛋白含量的影响不具有统计学意义;淀粉和维生素C随着密度的大幅增加而降低,其中RS25处理的淀粉较CK降低了5.57%,RS25处理的维生素C较CK降低了7.96%,同时RS35与CK处理不具有统计学意义.综上所述,种植密度为6.67×10⁴ 株/hm²的RS35处理马铃薯高产优质,且水分利用效率最高,为黑龙江地区滴灌马铃薯较为适宜的种植密度.     

应用~(15)N示踪探究楸树无性系对氮素的吸收和分配

为探讨楸树无性系对氮素的吸收、分配及利用特性,以2年生楸树无性系015-1、1-3、7080、1-4和004-1组培苗为试验材料,应用15N示踪技术对楸树无性系进行施肥试验。结果表明,5个楸树无性系氮肥的吸收率、利用率及分配率具有较强的一致性,氮肥利用率介于27.14%~31.24%之间。楸树无性系根和叶的肥料氮比例(Ndff)明显大于茎,楸树无性系根和叶对氮肥的竞争力较强,茎对氮肥的竞争力最弱。015-1茎部氮素分配率及无性系7080根部氮素分配率明显高于其他4个无性系;氮素分配率在各个器官中差异显著,叶片氮素的分配率最高,总体趋势为叶根茎。本研究结果为楸树氮肥的合理施用提供了理论依据。