【作者】 张旭；

【导师】 塔娜；

【作者基本信息】 内蒙古农业大学 ， 农业机械化工程， 2022， 博士

【摘要】 《中共中央国务院关于做好2022年全面推进乡村振兴重点工作意见》,即2022年中央一号文件,再次提到保障“菜篮子”产品供给,大力推进北方设施蔬菜基地的建设,加快发展设施农业,因地制宜发展塑料大棚、日光温室、连栋温室等设施。通过课题组多年对我国北方寒旱地区冬季日光温室内土壤水热的试验和研究,发现温室南侧边际区域,土壤温度长期处于低温状态。通过调研区域周边日光温室冬季种植情况,发现温室运营者针对温室南侧边际土壤温度低的现象,一般采用在南侧边际区域留有30～100cm的缓冲区域、增加供暖辅助、在温室南侧边际外埋设较厚的保温衬砌材料等,用以缓解温室南侧边际土壤温度低的现象,但上述方式存在一定缺陷,如降低了温室内土地的使用率、增加冬季种植运营成本、保温衬砌埋设不科学不但提升不到保温措施,反而造成人力、材料等成本的浪费。为解决该实际问题,本研究基于北方寒旱区日光温室(双层膜)为试验温室,在课题组多年对温室南侧边际的研究基础上,以及最大程度提高温室经济产出,降低改造投入成本,本研究以温室南侧边际不同形式的保温衬砌低导热材料为出发点,进行了2年不同保温衬砌形式的冬季试验。研究得出主要结论如下:(1)在不同保温衬砌材料及埋深的对比试验下,温室内距地表5cm,各试验区域土壤温度与土壤含水率呈负相关作用关系,该处保温衬砌对土壤温度变化影响较小;距温室南侧边际10cm和65cm处,距地表15cm及以下区域,保温衬砌对土壤温度的影响较大;距南侧边际120cm处,距地表15cm及以下区域,保温衬砌对土壤温度的影响逐渐减弱,土壤含水率对土壤温度的影响逐渐增强,且与土壤含水率呈正相关关系。通过对温室南侧边际处,南北方向边际界点的变化趋势分析,发现无保温衬砌组在距地表15cm及以下土壤层的边际界点效应强于保温衬砌组,埋深60cm的保温衬砌挤塑聚苯乙烯泡沫板组边际界点效应最弱。因此,相同埋深不同保温衬砌材料试验对比,挤塑聚苯乙烯泡沫板的隔热保温效果优于水泥砖;相同保温衬砌材料不同埋深时,得出保温衬砌埋深60cm时,能较好阻断温室内热量向温室外传递,其与非保温衬砌试验区的土壤温度差值范围为0.5～1.5℃。(2)在冬季大寒气候期间,选取埋深60cm的保温衬砌挤塑聚苯乙烯泡沫板,对温室外埋置不同厚度、温室内外埋置相同厚度、温室内埋置相同厚度的中部与边侧等试验组进行对比分析,发现保温衬砌挤塑聚苯乙烯泡沫板,其厚度对温室南侧边际土壤温度的影响较小,平均土壤温度差值不大于0.2℃,最大差值为0.3℃;温室内保温衬砌对阻挡温室内热量损失效果优于温室外保温衬砌,平均土壤温度差值为0.8℃,最大差值为1.6℃,采用温室内或外保温衬砌,需根据温室种植及南侧边际区域的实际情况进行确定;温室南侧边际的中部与边侧在相同内保温衬砌下,其南侧边际中部区域高于边侧区域,最大温度差值范围为1.3～4.1℃,温差值表现为随着土壤深度的增加,差值逐渐减小,相同土层,越远离温室南侧边际区域,土壤温度差值越大。通过对温室内外相同厚度保温衬砌及非保温衬砌地基下土壤水热变化进行研究,得出保温衬砌与地基建造的关系,即当保温衬砌埋于温室外侧时,地基宽度应在承载力允许的情况下,越窄越好,以减缓地基下土壤对温室内土壤热量的吸收;当保温衬砌埋于温室内侧时,阻隔了热量向地基下土壤传递,地基宽度符合建筑标准即可。(3)选取冬季土壤温度“下降期”和“上升期”的实测数据,对温室南侧边际不同土壤深度与土壤水热稳定性(方差、极值比、变异系数)进行分析,土壤温度的稳定性在两时期均表现为随土壤深度的增加而递减,土壤温度“上升期”比“下降期”更稳定,非保温衬砌组土壤温度的稳定性在相同深度时均低于保温衬砌组,表明非保温衬砌组土壤温度变化剧烈、变异程度大、土壤水热变化不稳定;土壤温度的稳定性与土壤深度均可用单指数函数进行描述,函数的拟合度~2在0.867～0.999范围内。土壤含水率多呈现随土壤深度增加,稳定性不断增强,但个别区域该规律性较差,土壤含水率“上升期”比“下降期”更稳定,距温室南侧边际120cm处,土壤含水率的稳定性低于距温室南侧边际10cm和65cm处。(4)运用灰色关联和BP神经网络理论,根据温室内外环境因子,对温室南侧边际土壤水热进行预测。各试验区域的环境因子与土壤温度关联性表现为:挤塑聚苯乙烯泡沫板保温衬砌的环境因子与土壤温度关联度系数最小,表明挤塑聚苯乙烯泡沫板的保温衬砌更能有效阻止土壤水热的运移,同时,选取关联度大于0.6的环境因子,建立温室南侧边际土壤温度传递函数,并选取不同连续时间实测数据进行函数验证;基于BP神经网络对温室南侧边际不同深度土壤进行水热预测,根据环境因子对温室南侧边际不同深度土壤水热进行了预测研究,并根据经验参数对多种试验进行了对比,得出隐含层为2层,且各隐含层节点数与输入节点数相同时,预测效果较好,土壤含水率的预测最大绝对误差值为0.3%,土壤温度最大绝对误差值为0.2℃;当上一层土壤水热的预测值作为输入值时,土壤含水率的预测最大绝对误差值为0.7%,土壤温度最大绝对误差值为0.3℃,误差小,预测结果较理想。(5)建立了不同保温衬砌结构下“温室外-保温衬砌-温室内”的土壤水热耦合模型,运用瞬态法进行求解。通过模拟得出,24小时内各保温衬砌试验组,其土壤等温线由“┌”型向“┃”型变化,再由“┃”型向“┐”型变化,最后变化为“┌”型,距地表15cm以上区域土壤温度变化波动范围较大。通过土壤水热耦合模拟,对不同保温衬砌及埋置深度和相同保温衬砌材料埋深的温室外埋置不同厚度、温室内外埋置相同厚度等试验区域进行了模拟对比分析。由于保温衬砌与非保温衬砌交界区域存在土壤温度缓冲区域,通过试验与模拟的方法,对交界处土壤温度变化进行模拟分析,得出在温室内侧或外侧东西方向埋设保温衬砌时,每块挤塑聚苯乙烯泡沫板的间隔不应大于20cm。(6)在不同保温衬砌结构土壤水热耦合模拟研究的基础上,对其进行二次开发,建立了一种只对保温衬砌材料的物理属性、埋深、厚度等进行设置的APP,基于该模拟APP进行不同形式的保温衬砌模拟对比试验,并与本研究相同保温衬砌形式下的试验与模拟结果相吻合,验证了该模拟APP的可应用性,为下游温室管理人员对温室南侧边际保温衬砌的设计提供了模拟参考和理论依据。更多还原

【Abstract】 The"Opinions of the Central Committee of the Communist Party of China and the State Council on Doing a Good Job in Promoting the Key Work of Rural Revitalization in2022",namely the No.1 Central Document in 2022,once again mentioned ensuring the supply of"vegetable basket"products,vigorously promoting the construction of vegetable bases in northern facilities,and accelerating the development of facility agriculture.Develop plastic greenhouses,solar greenhouses,multi-span greenhouses,and other facilities according to local conditions.Investigating the operation of the surrounding greenhouses found that,in response to the phenomenon of low marginal soil temperature of the greenhouse,greenhouse operators generally used a buffer area of 30-100 cm in the southern marginal area,increase heating assistance,and bury thicker thermal insulation outside the southern margin of the greenhouse.Lining materials,etc.,were used to alleviate the phenomenon of low marginal soil temperature on the southern side of the greenhouse.However,the above methods reduced the utilization rate of the land in the greenhouse,increase the cost of planting and operation in winter,and the unscientific burying of the thermal insulation lining not only failed to improve the thermal insulation measures but also caused labor costs,wasted of materials and other cost.To solve this practical problem,this study was based on the typical double-film solar greenhouse in cold and arid regions as the experimental greenhouse,and the research group had been researching the southern margin of the greenhouse for many years,to maximize the economic output of the greenhouse and reduce the cost of renovation.In this study,different forms of thermal insulation lining materials with low thermal conductivity on the southern edge of the greenhouse were taken as the research starting point,and a two-year winter experiment was carried out.The main conclusions of the study were as follows:(1)Under the comparative test of different thermal insulation lining materials and burial depths,the distance between the inside of the greenhouse was 5 cm from the surface,and the soil temperature in each test area was negatively correlated with the soil moisture content.At the margins of 10cm and 65cm,and 15cm and below the surface,the thermal insulation lining had a greater impact on soil temperature;at 120cm from the southern margin,15cm and below the surface,the impact of thermal insulation lining on soil temperature was gradually weakened,and soil moisture content the effect on soil temperature gradually increased and was positively correlated with soil moisture content.By analyzing the changing trend of the boundary points on the southern side of the greenhouse and the boundary points in the north-south direction,it was found that the boundary point effect of the non-insulation lining group in the soil layer 15 cm and below the surface was stronger than that of the insulation lining group.The marginal boundary point effect was the weakest in the polystyrene foam board group.Therefore,in the test comparison of different thermal insulation lining materials with the same burial depth,the thermal insulation effect of extruded polystyrene foam board was better than that of cement bricks;when the same thermal insulation lining material was buried in different depths,it was concluded that the thermal insulation lining could be better when the buried depth was60 cm.Block the heat transfer in the greenhouse to the outside of the greenhouse,and the soil temperature difference between it and the non-insulation lining test area ranged from0.5 to 1.5°C.(2)During the severe cold climate in winter,the thermal insulation lining extruded polystyrene foam board with a buried depth of 60cm was selected,and the experimental groups were embedded with different thicknesses outside the greenhouse,the same thickness inside and outside the greenhouse,and the middle and sides with the same thickness inside the greenhouse.Through comparative analysis,it was found that the thickness of the thermal insulation lining extruded polystyrene foam board has little effect on the marginal soil temperature on the south side of the greenhouse.The average soil temperature difference was not greater than 0.2°C,and the maximum difference was0.3°C,the effect of blocking heat loss in the greenhouse was better than that of the external thermal insulation lining.The average soil temperature difference was 0.8°C,and the maximum difference was 1.6°C.The use of internal or external thermal insulation lining in the greenhouse should be based on the actual conditions of greenhouse planting and the southern marginal area determined,under the same inner thermal insulation lining,the middle and side of the southern margin of the greenhouse,the central area of the southern margin was higher than the side area,and the maximum temperature difference ranges from 1.3 to 4.1°C,and the temperature difference showed that with soil depth.With the increase,the difference gradually decreases.In the same soil layer,the farther away from the southern marginal area of the greenhouse,the larger the soil temperature difference.By studying the changes of soil water and heat under the same thickness thermal insulation lining and non-insulating lining foundation inside and outside the greenhouse,the relationship between thermal insulation lining and foundation construction was obtained,when the thermal insulation lining was buried outside the greenhouse,the width of the foundation should be within the allowable bearing capacity.The narrower the better,to slow down the absorption of heat from the soil under the foundation to the soil in the greenhouse;when the thermal insulation lining was buried inside the greenhouse,it blocks the heat transfer to the soil under the foundation,and the width of the foundation can meet the building standards.(3)Selecting the measured data of the soil temperature"falling period"and"rising period"in winter,to analyze the soil depth and soil hydrothermal stability(variance,extreme value ratio,variation coefficient)at the southern margin of the greenhouse,the stability of soil temperature was both periods showed a decrease with the increase of soil depth,the soil temperature in the"rising period"was more stable than the"falling period",and the stability of the soil temperature in the non-insulation lining group was lower than that in the insulation lining group at the same depth,indicating that the non-insulation lining group was less stable.The soil temperature in the lining group changed drastically,with a large degree of variation,and the change of soil water and heat was unstable,the stability of soil temperature and soil depth could be described by a single exponential function,and the fitting degree R~2 of the function was in the range of 0.867-0.999.The soil moisture content tended to increase with the increase of soil depth,and the stability was continuously enhanced,but the regularity was poor in some areas,and the soil moisture content was more stable in the"rising period"than in the"falling period".The stability was lower than 10cm and 65cm from the southern edge of the greenhouse.(4)Using grey correlation and BP neural network theory,according to the environmental factors inside and outside the greenhouse,the marginal soil water and heat on the southern side of the greenhouse were predicted.The correlation between environmental factors and soil temperature in each test area was shown as follows:the environmental factor of extruded polystyrene foam board insulation lining had the smallest correlation coefficient with soil temperature,indicating that the thermal insulation lining of extruded polystyrene foam board can effectively prevent soil at the same time,environmental factors with a correlation degree greater than 0.6 were selected to establish the marginal soil temperature transfer function on the southern side of the greenhouse,and different continuous time measured data were selected to verify the function;based on the BP neural network,the soil temperature on the southern side of the greenhouse with different depths the water and heat prediction was carried out,and the soil water and heat at different depths on the southern margin of the greenhouse were predicted according to environmental factors,and various experiments were compared according to empirical parameters,and it was concluded that there are two hidden layers,and each hidden layer node when the number was the same as the number of input nodes,the prediction effect was better,the maximum absolute error value of soil moisture content prediction was 0.3%,and the maximum absolute error value of soil temperature was 0.2℃;when the predicted value of soil water and heat in the previous layer was used as the input value,the maximum absolute error value of soil moisture content prediction was 0.7%,the maximum absolute error value of soil temperature was 0.3℃,the error was small,and the prediction result was ideal.(5)The soil water-heat coupling model of"outside the greenhouse-insulation lining-inside the greenhouse"under different thermal insulation lining structures was established,and the transient method was used to solve it.Through the simulation,within24 hours,the soil isotherms of each thermal insulation lining test group changed from"┌"type to"┃"type,then from"┃"type to"┐"type,and finally changed to"┌"type,the soil temperature in the area above 15cm above the surface fluctuates widely.Through the soil water-heat coupling simulation,the simulation comparison was carried out on the experimental areas with different thermal insulation linings and buried depths and the same thermal insulation lining material buried with different thicknesses outside the greenhouse and the same thickness inside and outside the greenhouse.Since there was a soil temperature buffer area at the interface between the thermal insulation lining and the non-thermal insulation lining,through the method of test and simulation,the soil temperature change at the interface was simulated and analyzed,and it was concluded that when the thermal insulation lining was buried in the east-west direction inside or outside the greenhouse,each extruded plastic The spacing of polystyrene foam boards should not be greater than 20cm.(6)On the basis of the soil hydrothermal coupling simulation research of different thermal insulation lining structures,the secondary development was carried out,and an APP was established that only sets the physical properties,burial depth,thickness,and burying position of thermal insulation lining materials.Based on the simulation APP,different forms of thermal insulation lining simulation comparison tests were carried out,and the results were consistent with the test and simulation results under the same thermal insulation lining form in this study.Based on the marginal characteristics of the south side,the thermal insulation lining design provides a simulation reference and a theoretical basis for the design.更多还原