Study on Temperature and Humidity of Plastic Greenhouse under Different Ventilation Modes in the Yangtze-Huai Region in Hot Season

In order to analyze the ventilation and cooling performance of single-tunnel plastic greenhouse in Yangtze-Huai region, the effects of two different ventilation modes （side window, side window＋roof window） on the temperature and humidity of plastic greenhouse were studied. The results showed that the ventilation mode of opening side window and roof window could effectively reduce the temperature and humidity at the plant canopy height, which was conducive to the growth of plant in greenhouse.

Standard Operating Procedure of Houttuynia cordata Thunb.Plastic Greenhouse Cultivation

This standard operating procedure stipulated the natural condition of pro- ducing area, cultivation technique, disease and pest control, harvest, quality stan- dard, packaging, transportation and storage of H. cordata, in order to provide a ba- sis for the standard cultivation of H. cordata.

Salt Contents in Soils Under Plastic Greenhouse Gardening in China

Field experiments were conducted on three main soils, brown soil, meadow soil and cinnamon soil, of Shandong Province to study the effect of plastic greenhouse gardening on soil salt contents. As compared to the open fields, the soil nutrient contents in the fields under plastic greenhouse gardening all increased significantly. The organic matter, quickly available N and P increases were extremely significant and the quickly available K increase was also significant. Along with the nutrient increases the soil salt contents increased clearly in all the soils investigated not only in the top layer but also in the deeper layers, being extremely significant in the 0～10 cm layer and significant in the 10～40 cm layers. The salt contents in the plastic greenhouses had significant correlations with the soil available nitrogen and phosphorous. Soils with longer plastic greenhouse gardening time tended to have more salt. The plastic greenhouse soils contained less CO-3～(2-) and much more NO-3 than the open soils, which indicated a higher influence of human intervention in plastic greenhouses. Among the constituent ions, Cl～(-), NO-3～(-) , Ca～(2+) and Mg～(2+) had positive while HCO-3～(-) had negative significant or extremely significant correlations with total salt, with correlation coefficients being 0.66*, 0.80**, 0.92**, 0.80** and -0.64* , respectively. Nitrate decreased from the top to deeper layers both in the plastic greenhouses and in the open fields. The plastic greenhouse soils contained much more nitrate than the open fields in every layer and even the nitrate contents of the 80～l00 cm layer were still several times those of the top layer in the open fields. The main reason for the salt increases was considered to be the inappropriate fertilization and selective absorption of nutrients by plants in the plastic greenhouses. The methods recommended to avoid soil salt increase in the plastic greenhouses were to apply fertilizers rationally according to the soils, vegetables and fertilizer properties and to adopt a good intercropping or rotation system.

Analysis of Phthalate Esters in Air, Soil and Plants in Plastic Film Greenhouse

The phthalate esters such as DMP, DEP, DBP and DEHP in air, soil and plant samples in plastic film greenhouse were clean up with fine silica gel column and determined with HPLC. It was found that the concentrations of PEs in air and soil samples in plastic film greenhouse are much higher than those of contrast samples. But concentrations of PEs in plants in plastic film greenhouse are not remarkably affected by the pollution of air and soil.

Effects of plastic film mulching on soil greenhouse gases(CO2,CH4 and N2O) concentration within soil profiles in maize fields on the Loess Plateau,China

To better understand the effects of plastic film mulching on soil greenhouse gases（GHGs） emissions,we compared seasonal and vertical variations of GHG concentrations at seven soil depths in maize（Zea mays L.） fields at Changwu station in Shaanxi,a semi-humid region,between 2012 and 2013.Gas samples were taken simultaneously every one week from non-mulched（BP） and plastic film-mulched（FM） field plots.The results showed that the concentration of GHGs varied distinctly at the soil-atmosphere interface and in the soil profile during the maize growing season（MS）.Both carbon dioxide（CO_2） and nitrous oxide（N_2O） concentrations increased with increasement of soil depth,while the methane（CH_4）concentrations decreased with increasement of soil depth.A strong seasonal variation pattern was found for CO_2 and N_2O concentrations,as compared to an inconspicuous seasonal variation of CH_4 concentrations.The mean CO_2 and N_2O concentrations were higher,but the mean CH_4 concentration in the soil profiles was lower in the FM plots than in the BP plots.The results of this study suggested that plastic film mulching significantly increased the potential emissions of CO_2and N_2O from the soil,and promoted CH_4 absorption by the soil,particularly during the MS.

Biological Characteristics of Fusarium oxysporum f. sp.niveum Isolated from Watermelon Cultivated in Plastic Greenhouse and Indoor Toxicity Determination of Different Fungicides in Hainan Province of China

[ Objective] The paper was to study biological characteristics of Fusarium oxysporum f. sp. niveum in watermelon cultivated in plastic greenhouse in Hainan Province of China and to determine indoor toxicity of fungicides. [ Method] Effects of various factors on mycelial growth and spore germination were stud- ied, and the lethal temperature of spores and indoor toxicity of fungicides were also determined. [Result] The fungal mycelium had a better growth rate on water- melon juice medium than the others. The optimum temperature for mycelial growth and spore germination were 28 ℃ and 30 ℃, and the optimum pH values were 7 - 8 and 7 - 9, respectively. Light-dark alternation was conducive for mycelial growth. The lethal temperature of spore was 60 ℃ for 5 min. The fungal mycelium grew better while taking fructose and glucose as carbon sources and yeast extract and peptone as nitrogen sources. Toxicity determination showed that 50% pro- chloraz-manganese chloride complex WP had the greatest inhibition effect on mycelial growth, with the ECso value of 0.730 9 μg/mL; followed by 32.5% benzoic azoxystrobin SC, 30% benzoylate· propieanazol EC, 10% difenoconazole WG, 25% bromothalonil · carbendazim WP and 25% bromothalonil WP, with the ECso values from 1.884 7μg/mL to 8. 161 0μg/mL. [Conclusion] The study provided basic data for field control against F. oxysporum f. sp. niveum on watermelon cultivated in plastic greenhouse in Hainan Province.

Research and Analysis on Cooling Capacity of Temperature Adjustment Equipments in Agricultural Multi-span Greenhouse

The high summer indoor temperature in agricultural greenhouse is not conducive to crop growth,so it is necessary to cool the greenhouse. In this study,taking the agricultural multi-span greenhouse with strong temperature adjustment ability for example,we make an experimental analysis on the temperature changes inside and outside the greenhouse under nine different equipment combinations( fan,skylight,sunshade,sunshade + fan,cooling pad + fan,skylight + fan,sunshade + skylight,sunshade + fan + cooling pad,sunshade + skylight + fan),respectively,and conduct the overall assessment on the measures to cool the summer agricultural greenhouse,in order to provide a reference for selecting a cost-effective cooling method for greenhouse. Tests show that the three treatment modes of fan,sunshade and sunshade + fan almost have no cooling capacity; skylight,sunshade + skylight have cooling capacity,but the effect is slow; cooling pad + fan,sunshade + skylight +fan can reduce the indoor temperature,but the effect is not very good; skylight and fan have good cooling effect; sunshade + fan + cooling pad has obvious cooling effect,which can well meet the cooling needs in the summer greenhouse.

Impacts of Micro- and Nano-Plastics on Soil Properties and Plant Production in Agroecosystems: A Mini-Review

Micro- and nano-plastics (MNPs) are tiny plastic particles resulting from plastic product degradation. Soil MNPs have been identified as potential influential factors affecting various soil properties and crop biomass productivity. This mini-review provides a synthesis of recent findings concerning their effects on soil physicochemical properties, microorganisms, organic carbon content, soil nutrients, greenhouse gas emissions, soil fauna, and their impacts on plant ecophysiology, growth, and production. The results indicate that MNPs may markedly impede soil aggregation ability, increase porosity, decrease soil bulk density, enhance water retention capacity, influence soil pH and electrical conductivity, and escalate soil water evaporation. Exposure to MNPs may predominantly induce changes in soil microbial composition, reducing the diversity and complexity of microbial communities and microbial activity while enhancing soil organic carbon stability, influencing soil nutrient dynamics, and stimulating organic carbon decomposition and denitrification processes, leading to elevated soil respiration and methane emissions, and potentially decreasing soil nitrous oxide emission. Additionally, MNPs may adversely affect soil fauna, diminish seed germination rates, promote plant root growth, yet impair plant photosynthetic efficacy and biomass productivity. These findings contribute to a better understanding of the impacts and mechanistic foundations of MNPs. Future research avenues are suggested to further explore the impacts and economic implications.

Experimental research on the microclimate in the naturally ventilated multi-span greenhouse

In order to further understand the changing laws of environmental factors in large multi-span greenhouses under natural ventilation conditions and the internal relations between various environmental factors,and ultimately improve the precision of microclimate regulation of large multi-span greenhouses.Taking the multi-span greenhouse with a small spire structure in the Demonstration Base of Guangdong Agricultural Technology Extension Station as the research object,under the condition of natural ventilation with butterfly-shaped windows,the changes in temperature,humidity,wind speed and solar light intensity of different monitoring planes in the greenhouse were monitored.After analyzing the monitoring data,it was found that:1)The temperature gradient in the vertical direction in the large multi-span greenhouse is more obvious than that in the small greenhouse,and the highest average temperature difference monitored can reach 7.9℃.The velocity field in the multispan greenhouse is always maintained within the range of 0.3-0.4 m/s,and the ambient wind speed has no effect on the airflow speed in the greenhouse.The humidity and speed in the multi-span greenhouse show good uniformity.2)In a large multi-span greenhouse,the secondary radiation generated by the internal shading has less impact on the area near the ground,which can effectively reduce the ground temperature.3)Under the conditions studied in this research,the temperature and humidity in the greenhouse follow the external environment as well,showing that the greenhouse design is reasonable,and the air renewal and heat exchange inside and outside the greenhouse are good during natural ventilation.

CFD Based Study of Heterogeneous Microclimate in a Typical Chinese Greenhouse in Central China

Indoor microclimate is important for crop production and quality in greenhouse cultivation. This paper focuses on microclimate study based on a computational fluid dynamics （CFD） model of a typical plastic greenhouse （with a sector shape vertical cross-section） popularly used in central China. A radiation model is added into the CFD model so as to simulate coupling of convective transfers and radiative exchanges at the cover and the roof, instead of using the usual coupling approach based on energy balance. In addition, a fractal permeability model is innovatively adopted in the modeling of the crop canopy. Compared the numerical results with measured experimental data, the model simulation is proved with success. This model then is used to explore the microclimate variable distributions in the greenhouse. It shows that the airflow pattern, temperature and humidity profiles are different from those in a sawtooth Mediterranean- type greenhouse. The study suggests that this deliberately developed CFD model can be served as a useful tool in macroclimate research and greenhouse design investigating.

北方地区塑料大棚内葡萄与香菇生态套种技术

基于葡萄树下套种香菇试验,总结出北方地区塑料大棚内葡萄树下香菇半熟料畦床套种和香菇菌棒地表摆放套种两种生态套种模式,系统介绍了茬口安排、场地消毒、原料准备、原料处理、播种、发菌管理、转色管理、出菇管理和采收管理等不同栽培阶段的技术要点,并讨论了塑料大棚内葡萄香菇生态套种的注意事项。

塑料大棚萝卜-番茄-黄瓜一年三茬高效栽培技术规程

渭河流域河谷川道地区利用塑料大棚进行春番茄-秋黄瓜并套种萝卜的种植模式,实现了一年三茬高效栽培,这种模式在天水市武山县城关镇、洛门镇等地形成了一定规模。为促进武山县塑料大棚蔬菜产业健康可持续发展,根据国家及行业标准,结合多年试验示范和生产实践,从适用范围、规范性引用文件、产地环境、品种选择、茬口安排、栽培技术要点等方面总结制定了塑料大棚萝卜-番茄-黄瓜一年三茬栽培技术规程。本规程的制定将为武山塑料大棚多熟制蔬菜的发展提供有力的技术支撑,进而促进渭河流域塑料大棚蔬菜产业的高质量绿色标准化生产。

塑料大棚香瓜-番茄轮作生产技术

基于黑龙江省在保障粮食供给以及自然资发[2021]166号文件中严格控制农业设施建设用地使用一般耕地要求的两大背景下,开展塑料大棚一年两茬高效生产技术模式研究,形成地方标准1项,主要包括轮作茬口安排、香瓜生产技术、过渡期设施管理、番茄生产技术,以期建立以夏秋茬北菜南销番茄生产为主,早春抢早香瓜生产为辅的轮作模式,提升现有塑料大棚的产出率以及推进“北菜南销”塑料大棚番茄产业可持续发展。

桁架拱塑料大棚骨架平面内竖向荷载受力性能试验

桁架拱塑料大棚在我国北方寒区广泛使用且数量庞大。由于我国北方寒区雪荷载大,而多数大棚骨架设计制造不合规,冬季常有暴雪导致的大棚坍塌事故发生。为研究桁架塑料大棚骨架在平面内竖向荷载的受力性能,以节点间距及桁架拱高度为影响因素,研制了4榀桁架拱塑料大棚骨架及试验装置。采用竖向加载的方法得到了桁架拱塑料大棚骨架竖向荷载作用下的试验现象、骨架极限荷载及位移等试验数据。通过极限荷载数据分析得到了影响桁架拱塑料大棚骨架承载力因素排列顺序为:矢高>上弦节点间距>桁架高度。通过分析骨架荷载-位移曲线得到了骨架弹性极限荷载及对应的弹性位移,并通过分析骨架变形形态得到了骨架进入平面外屈曲的位置和屈曲状态。采用ABAQUS建立了桁架拱塑料大棚骨架三维线性有限元模型,通过跨中及l/4跨处的荷载-位移曲线试验值与模拟值对比分析,验证了有限元模型的正确性。研究成果可为桁架拱塑料大棚使用阶段受力和后续非线性屈曲稳定有限元分析提供参考。

山东省设施农业风灾风险评估研究

本研究利用气象观测、高分辨率卫星影像、灾情直报等数据,基于自然灾害风险理论,探索了设施农业风灾风险评估方法。以山东省为例,从设施农业风灾危险性、暴露度、脆弱性和防灾减灾能力4个方面,构建设施农业风灾风险评估指数,开展风险评估研究,并对评估结果进行了分析和验证。结果显示,风灾危险性受地形影响,高值区主要分布在鲁中山区和山东半岛;暴露度高值区分布符合设施种植建设用地规范,主要集中在鲁中的东部、鲁西北和鲁西南;脆弱性与基本风压反向分布较为吻合,中高值区主要分布在鲁南和鲁中的东部地区;防灾减灾能力较弱地区主要分布在成灾指数大、风灾预警能力相对较弱、经济欠发达的鲁西北、鲁西南和鲁中的西部;设施农业风灾风险高低由危险性、暴露度、脆弱性和防灾减灾能力共同决定,高风险区主要分布在鲁西北、鲁西南以及鲁中。经检验,设施农业风灾风险分布与风灾灾情发生情况空间上具有显著一致性,基于自然灾害风险理论构建的设施农业风灾害风险评估指数合理、方法可行,结果可为设施农业风灾风险管理以及防灾减损提供参考。

基于物联网的塑料大棚保温被自动揭放对越冬叶菜生长及品质的影响

【目的】为研究应用物联网系统调控塑料大棚保温被的自动揭放,对越冬叶菜生长及品质的影响。【方法】以每日日出日落时间为依据,针对不同气候环境,设计自动揭放保温被的环境条件阈值为处理H,园区管理员经验揭放时间为对照(CK)。两个塑料大棚内种植相同品种叶菜(小白菜、油麦菜、油菜、菠菜),对塑料大棚内叶菜的生长指标、品质及产量进行比较。【结果】基于物联网的自动控制系统能够有效监测温室内外光照强度、温度和湿度等环境信息,能进行保温被的自动揭放控制,并且该系统应用安全、方便、灵活。越冬叶菜3个生育期内,H处理比CK的平均空气温度和平均土壤温度分别高10.8%~21.3%和10.1%~23.2%,对叶菜的生长发育以及品质产量起到促进作用。【结论】物联网系统控制保温被揭放的塑料大棚具有良好的环境性能,可解决冬季叶菜缺乏问题,具有推广价值。

辽宁地区葡萄不下架防寒模式探讨

葡萄下架埋土防寒一直是北方葡萄防寒区产业发展的重要制约。文中论述了辽宁地区葡萄不下架越冬的几种栽培模式,包括日光薄膜温室、塑料大棚、连栋大棚栽培中葡萄不下架越冬方法,并对比分析了其优缺点,其中塑料大棚采用二道拱防寒越冬方法既节约了成本又能优产高产,且建造投入低,是一种较优的不下架越冬模式,在北方寒冷地区应用前景广阔,值得进一步研究、推广。

我国塑料大棚结构优化及性能研究现状

塑料大棚作为农业设施主要类型之一,在解决我国北方地区淡季吃菜难、提供鲜嫩蔬菜上有着重要作用。但在实际生产中,因塑料大棚所在地理环境恶劣和其结构与建造缺陷等,棚室结构难以抵抗暴风、暴雪等极端恶劣天气,且可能存在光热环境不好、稳定性不足等问题。该文介绍了塑料大棚的发展与主要结构类型,对近年来塑料大棚结构创新优化与性能研究进行了归纳总结,分析了其结构在生产中的实际问题,提出了未来发展相关建议。

农机农艺融合条件下塑料大棚黄瓜适度规模化生产技术

针对北京地区蔬菜种植设施面积小、种植零散问题,借鉴工业生产的思维模式,开展适度规模化管理模式,以塑料大棚黄瓜为例进行生产示范,统一育苗、定植、水肥管理、植株调整等环节的操作标准,通过互联网智能化手段监测大棚内环境条件、植株生长状态、病虫害发生等情况,针对灌水、施肥、采收等关键技术环节,集成省力化精准作业模式,缓解作业强度,实现农技、农机和设施的深度融合。

高温越夏日本大葱种质表型性状差异及亲缘关系研究

为了鉴定、筛选出越夏高产大葱种质并用于耐高温品种改良和选育,以42份日本大葱种质为试材,采用形态鉴定方法,在塑料大棚环境下研究了经高温越夏后种质的表型性状差异和亲缘关系远近,并用隶属函数法对初筛种质进行综合评价。结果表明:42份种质单株质量、株高、假茎质量、假茎长、假茎直径、叶长、叶扁宽、宿存叶片数、假茎指数和叶形指数10个数量性状的变异范围为10.50%~38.60%,平均值为19.62%。其中,假茎质量和单株质量变异系数较高,分别为38.60%和37.23%。经聚类分析将42份种质聚为1个高细类型、1个矮细类型、2个矮粗类型亚组共计4个组群,组群间性状差异显著。采用隶属函数法对高细类型、矮粗类型第1亚组14份种质进行种质综合评价,排名为喜太郎晚抽、玖源晚抽、什全一本、夏力源、成田一本、智荣、玖美、咏秀、荣辉、金春一本、卡曼、盛源泰32号、川田一本和揽胜。该研究从形态学角度解析了越夏日本大葱种质遗传差异,明确了不同资源亲缘关系远近,为越夏大葱种质筛选和优势杂交育种亲本选择提供了依据。