日光温室内黄瓜群体结构参数分析

日光温室由于其特殊的光环境,黄瓜群体结构也具一定的特殊性,试验观测了日光温室内南北部的光环境及黄瓜不同生育时期的群体结构参数.结果表明:日光温室内南部的辐射强度明显高于北部,黄瓜的叶倾角、叶方位角、叶面积指数、叶面积密度等黄瓜群体结构因素在不同时期有明显的变化.植株南面叶片的叶倾角大于植株北面叶片的叶倾角.在整个生育期黄瓜以30°～40°叶倾角的叶片为分布主体.植株南面方位角分布频率也高于植株北面的方位角分布频率.叶面积指数和叶面积密度在生育前期上升,后期下降,这些变化与差异对黄瓜群体内的辐射分布有重要影响,所以此结果为探讨日光温室内的黄瓜群体结构与群体内辐射分布的关系和建立群体内辐射分布的数学模型奠定了基础.     

日光温室放风方式相关指标分析

通过调研从放风的操作难易程度、对棚膜的磨损程度及通风量大小等指标分析了目前温室的几种常用放风方式.比较了第5种类型和第6种类型放风方式的特点,计算了自然通风条件下日光温室所需的通风量,并依据"质量守恒原理"计算了在热压作用下,以上2种通风方式的风口面积.结果表明:第6种类型放风方式的筒口半径为 25cm,风筒高度为50 cm,屋脊处沿东西方向的布置间距为100cm.前底脚处通风口的有效宽度为20cm条件下基本能满足通风要求.该方法具有操作灵活方便,避免磨损棚膜,利于保护棚膜等优点.第5种类型放风方式在满足屋脊处和前底脚处风口最小宽度为23 cm条件下基本能满足通风要求,该方式能保持棚膜始终处于张紧的状态,不影响采光,磨损棚膜易于更换.     

大跨度温室屋面建设问题商榷

结合工程实例,针对温室工程建设中,采用双层充气膜屋面覆盖出现的兜水、漏水和其他构造问题,分析产生问题的原因,并介绍解决问题的技术措施.     

大花蕙兰温室管理技术

从大花葱兰的温室培养所需要的各种条件:温度、相对湿度、光照、栽培基质、水、肥以及病虫害等方面,对大花蕙兰的温室管理进行了讨论,并对其管理过程提出了相应的措施.     

黄土高原雨养农业区不同种植模式土壤温室气体排放特征

研究陇中黄土高原旱作农田,设置了苜蓿-苜蓿(L-L)、苜蓿-休闲(L-F)、苜蓿-小麦(L-W)、苜蓿-玉米(L-C)、苜蓿-马铃薯(L-P)和苜蓿-谷子(L-M)6个处理,采用静态箱-气相色谱法和碳通量测量系统LI-8100对苜蓿后茬轮作不同作物土壤温室气体排放动态及其影响因素进行了测定与分析。研究结果表明,农田土壤表现为CO₂源、N₂O源和CH₄吸收汇,且呈现夏秋高,春冬低的季节性变化特征。L-L处理的CO₂累积排放量最高,L-W处理较之降低了42.43%;L-C处理的N₂O累积排放量最高,L-P处理最低;CH₄吸收量以L-M处理最高,较L-F和L-L分别增加了62.71%和31.87%,综合增温潜势表现为L-L>L-M>L-C>L-P>L-F>L-W。相关分析结果表明,CO₂、CH₄、N₂O排放量与脲酶、过氧化氢酶活性及土壤温度呈极显著相关(P<0.01),与土壤水分在不同土层有显著相关性;逐步回归分析发现,土壤温度、过氧化氢酶是CO₂和CH₄排放的主导因素,土壤温度极显著影响气体排放,N₂O排放主要受到环境因子的影响。综合来看,与长期苜蓿连作相比,黄土高原地区苜蓿种植一定年限之后轮作粮食作物能减少土壤温室气体排放量,减弱农田温室气体的增温效应,其中以小麦效果最佳。     

设施蔬菜次生盐渍化防控效果浅析

为了有效解决设施蔬菜土壤次生盐渍化问题,实现设施蔬菜生产的健康可持续发展,以南京市江宁区设施蔬菜生产基地为调研对象,通过调查分析后发现设施内土壤pH值显著低于露地,且EC值和NO_3~--N含量显著高于露地,表明设施土壤盐渍化及酸化严重。然后有针对性地提出了相应的解决措施,如选择耐盐品种、改进浇水方法、合理施肥等。     

Dose–response effect of a pine bark extract on in vitro ruminal ammonia and methane formation kinetics

ABSTRACT

This study assessed the potential of a pine bark extract (PBE) to decrease methane (CH₄) and ammonia nitrogen (NH₃-N) production in vitro. Dietary substrates, mixed hay, soybean meal and corn grain, were supplemented 0, 2, 4 and 6% of PBE and incubated in an in vitro batch culture for 24-h. Incubations were run three times. Total gas production (GP) was determined at 6, 12 and 24-h and gas samples were analysed for CH₄. Samples were collected for volatile fatty acids (VFA) and NH₃-N analysis. Treatments were compared by polynomial contrasts for PBE concentration. Increasing PBE caused linear decreases in NH₃-N, microbial biomass production and digestibility, whereas the degradation rate was quadratically reduced. Total VFA were decreased but total GP and CH₄ production and kinetics were unaffected. The inclusion of 2% PBE in ruminant feed has the capability to reduce NH₃-N concentration by 50%, without affecting diet digestibility or CH₄ production.     

将地板采暖系统用于温室种植中的研究

为了在温室种植中取得更好的效果；结合现有供热方式，将优化的地板采暖系统运用在温室中。经过研究，地板采暖系统在温室种植中取得了不错的效果，得到的计算数据可以为日后工作中地板采暖系统的运用和推广提供参考和依据，并对地板采暖系统在冬季温室种植中的应用做了进一步的优化和比较。     

江苏沿海地区单体大棚棚型结构研究与分析

通过对盐城地区主要单体大棚棚型结构研究与分析,指明各单体大棚棚型结构的优缺点,在此基础上研究形成符合本地区气候特点、具有适用性和针对性的优化型大棚结构。     

Fulvic acid displaces manure to improve soil in vegetable greenhouse

Acid soil has led to a significant decrease in vegetable yield in high-yield greenhouse vegetable production system. Chicken manure and fulvic acid (FA) application experiment was conducted to evaluate the effects on chemical properties of soil in vegetable greenhouse so as to confirm whether FA could replace chicken manure in acid soil amelioration under the same addition levels of nutrient, when compared to the effect of chemical fertilizers application alone on acid soil improvement. The results showed that the pH of soil added with chicken manure and FA, respectively, increased from the original value of 5.4 to 5.99 and 6.32 at the end of the experiment, while soil pH applied only with chemical fertilizers decreased to 5.43. Correlation analysis indicated that cation exchange capacity (CEC) of soil was positively correlated with soil pH buffering capacity. The peak values of soil CEC and pH buffering capacity occurred in April each year and subsequently tended to decrease in August and December throughout the experiment. Data demonstrated that chicken manure and FA in combination with soil contributed to soil base saturation that increased from 26.5%, 33.8% to 36.7%, 45.9% in chicken manure and FA treated soil during December 2011 to December 2012, respectively; however, chemical fertilizers displayed an adverse effect on soil base saturation that decreased from 17.1% to 5.6% on the same time period. Exchangeable aluminum (Al) concentration showed a weak but significant increase by 5.2% on August 2012 in comparison to April 2012, as chemical fertilizers were added into soil alone. Unlike to chemical fertilizer, chicken manure and FA significantly decreased soil exchangeable Al concentration from the original value of 5.37 cmol kg^?1 to 4.56 and 4.22 cmol kg^?1 at the end of experiment respectively. Compared to total yield treated solely with chemical fertilizers, chemical fertilizers combination with chicken manure or FA resulted in an increase in total yield in 2011 and 2012. Although chicken manure and FA possessed the same trend of improving acidic soil in vegetable greenhouse, a greater contribution was attributed to FA due to its lower mineralization rate of organic matter. Therefore, it was suggested that FA could completely displace chicken manure in improvement in acidic soil in vegetable greenhouse.