施肥与大气环境质量——论施肥对环境的影响(1)

无机肥和有机肥都是人类可持续发展不可或缺的资源,只要科学使用不会对环境和生态造成负面影响。不良施肥对大气环境的威胁主要来自有机肥,过量使用有机肥可促进土壤中CO2和CH4的排放;有机肥和畜禽粪肥堆放场地有大量氨气污染,有机物的焚烧可直接向大气排放大量的CO2、CH4及固体微粒,使城乡空气严重污染。有机肥和无机N肥的过量使用,都会导致土壤N素积累。土壤中N素的反硝化作用产生N2O, NOx 的排放。避免有机肥和N肥过量,禁止焚烧有机物,覆盖有机肥和畜禽粪肥堆放场,控制反硝化作用,以减少负面效应,保护大气环境质量。     

Fluxes of CO2, CH4 and N2O from drained organic soils in deciduous forests

We examined net greenhouse gas exchange at the soil surface in deciduous forests on soils with high organic contents. Fluxes of CO₂, CH₄ and N₂O were measured using dark static chambers for two consecutive years in three different forest types; (i) a drained and medium productivity site dominated by birch, (ii) a drained and highly productive site dominated by alder and (iii) an undrained and highly productive site dominated by alder. Although the drained sites had shallow mean groundwater tables (15 and 18 cm, respectively) their average annual rates of forest floor CO₂ release were almost twice as high compared to the undrained site (1.9±0.4 and 1.7±0.3, compared to 1.0±0.2 kg CO₂ m⁻² yr⁻¹). The average annual CH₄ emission was almost 10 times larger at the undrained site (7.6±3.1 compared to 0.9±0.5 g CH₄ m⁻² yr⁻¹ for the two drained sites). The average annual N₂O emissions at the undrained site (0.1±0.05 g N₂O m⁻² yr⁻¹) were lower than at the drained sites, and the emissions were almost five times higher at the drained alder site than at the drained birch site (0.9±0.35 compared to 0.2±0.11 g N₂O m⁻² yr⁻¹). The temporal variation in forest floor CO₂ release could be explained to a large extent by differences in groundwater table and air temperature, but little of the variation in the CH₄ and N₂O fluxes could be explained by these variables. The measured soil variables were only significant to explain for the within-site spatial variation in CH₄ and N₂O fluxes at the undrained swamp, and dark forest floor CO₂ release was not explained by these variables at any site. The between-site spatial variation was attributed to variations in drainage, groundwater level position, productivity and tree species for all three gases. The results indicate that N₂O emissions are of greater importance for the net greenhouse gas exchange at deciduous drained forest sites than at coniferous drained forest sites.     

固原地区百合日光温室栽培研究

通过对引进的6个百合栽培品种发育过程、主要性状的观测分析,综合比较各品种的生长情况和特性,结果表明：“木门”、“罗宾娜”、“索邦”、“西伯利亚”4个品种在长势、株型、花型、花期、抗冻性等方面比较优良,适合在固原地区日光温室栽培.     

鲁中山区大樱桃温室扣棚时间和升温时间分析

试验选取鲁中山区的3个大樱桃温室,进行从冬季扣棚开始至大樱桃升温期间温度等气象要素观测,同时结合温室管理人员对扣棚时间、升温时间的记录以及温室大樱桃的生长状况,研究温室大樱桃的扣棚时间和最合适的升温时间。结果表明,鲁中山区温室大樱桃扣棚时间在12月中下旬,当该时期外界温度下降至-19.1℃时,花芽冻坏率为30%,建议在该时期强冷空气来临之前扣棚;升温时间在次年1月上旬,升温时间要在满足需冷量的前提下,根据试验结果,7.2℃模型的最小需冷量为1 070 h,0~7.2℃模型的需冷量为484 h。     

Computer fluid dynamics prediction of climate and fungal spore transfer in a rose greenhouse

Fungal pathogens and especially grey mould are among the most virulent bio-aggressors of protected crops. A warm, moist greenhouse climate encourages the outbreak of explosive epidemics, of Botrytis cinerea in particular. The aim of this study was to simulate Botrytis spore concentration and deposition patterns in a greenhouse and model the inside climate conditions.The general flow equations were solved using the Fluent® CFD code with a simulation of the coupling between aerial transport and crop activity based on earlier research. A specific Eulerian particle transfer module was added to account for spore transfer with a new species: the Botrytis spore concentration. To describe the spore transport equation, the governing equations were modified, adding a vertical terminal velocity term accounting for the effect of gravity on the spores and sink terms accounting for spore interception by impaction or deposition.The necessary parameters for the model, together with spore concentration and climate boundary conditions, were determined in an experimental study of a rose greenhouse with roof and lateral vents equipped with insect-proof nets. These experimental devices have already been exploited for validating a ventilation model and a Botrytis spore balance. In addition to these previous studies, the present paper was essentially designed to determine greenhouse climate and spore concentration and deposition patterns.The accuracy of the inside-outside air temperature difference simulation is good but deteriorates for inside-outside air humidity. Spore transfer is also accurately simulated, with a mean error of only 0.2 sp m⁻³ for daytime and 0.53 sp m⁻³ for night time. The observed values of spore deposition show a similar order of magnitude to the simulations. However, validation was hindered by difficulties encountered in measuring spore deposition, even on an average daily time scale. Analysis of the heterogeneity of the simulated distribution of spore deposition and concentration revealed that, when the Botrytis spores came from outside, their concentrations in the air are filtered by the insect proof nets on the vent openings and then by the crop canopy - the rose stems, buds and leaves.Consequently, if, as in this case, no inoculums is produced inside the greenhouse, we note a considerable decrease in inside airborne spore concentration due to these various filters and considerable spore deposition on the crop cover near the vent openings where the air enters. This approach can provide information's on the patterns of inoculums deposition and climate conditions explaining the risks of future fungal development.     

不同栽培年限大棚土壤盐分变化特性研究

[目的]为了探明杨凌大棚土壤次生盐渍化的演变特性。[方法]以露天菜地为对照,运用相关及方差分析方法,研究了杨凌地区不同种植年限的大棚土壤水溶性盐分的变化特性。[结果]大棚土壤中水溶性总盐含量与电导率(EC)比露地蔬菜土壤明显增高,且随栽培年限的延长总盐含量与EC值逐渐升高,水溶性总盐与EC值在0-10cm土层呈线性正相关,R2=0.9106。对不同棚龄土壤总盐含量进行方差分析可知,F=16.977>F0.01=5.06,3、5年大棚土壤含盐量与其他处理之间有显著差异,3年大棚土壤与其他处理有极显著差异。随着栽培年限的延长,土壤pH值呈逐渐下降的趋势,在0-40cm土层,大棚土壤pH值随土壤层次加深而增高。8大离子组成中阴离子以SO42-为主,阳离子以Ca2+为主,分别占总盐的24.42%和21.46%。大棚土壤盐渍化趋势随栽培年限的延长越来越明显。[结论]确定了杨凌地区土壤盐渍化的演变规律,为解决设施农业发展中存在的土壤障碍问题提供了理论支持。     

基于农田温室系统的嵌入式USB主机系统

介绍了一套基于ARM内核处理器开发的USB主机系统,提出了基于S3C44B0X和SL811HST的系统解决方案,该系统成本低廉、运行稳定,适合应用于从温室系统中提取数据到U盘上。为USB在嵌入式领域的应用和实现USB的通信,提供了一个简便、可靠的方法。     

赤峰市丘陵坡地不同跨度日光温室综合性能比较分析

针对目前内蒙古自治区目光温室跨度建造不规范的现状,试验比较分析了赤峰市跨度分别为8．0m、8．5m、9．0m、9．5m和10．0m日光温室的光热特性、产量、生产成本以及投入产出比差异,结果表明：在其它建造参数不变的情况下,在该试验条件下,随着温室跨度增加,温室透光率、空气温度、空气湿度、土壤温度环境因子逐渐变优;平均667m^2产量逐渐增加,10m跨度日光温室秋冬茬番茄两年平均产量9310．4kg/67m^2,显著高于8m跨度产量8470．6kg／667m^2;建造成本、折旧成本、生产成本都在增加,但投入产出比也在增加,10m跨度投入产出比为1：3．8．而8m跨度为1：3．6     

日光温室间作新模式对环境因子及菇菜生长的影响

采用反遮光内拱棚模式,在日光温室内进行菇菜间作,研究对环境因子及菇菜生长的影响。结果表明:反遮光内拱棚日均温度15.5℃,最高22℃,最低12℃;相对湿度平均96.7%,最高99%,最低90%;光照强度最高为0.5klx;CO2平均浓度为828μL·L-1,最高为1000μL·L-1,最低为630μL·L-1,完全满足金针菇生长需求。通过斜拉秧措施,极大提高了黄瓜窄行光照强度,提高了保护地栽培效益。     

KH2PO4对设施油桃果实糖积累及代谢相关酶活性的影响

以设施栽培的艳光油桃为试材,研究了设施栽培条件下,喷施KH2PO4处理对油桃果实中糖积累和蔗糖代谢相关酶活性的影响。结果表明,幼果期喷施KH2PO4处理,果实葡萄糖和果糖含量明显增加,蔗糖含量没有明显变化,成熟期三种糖含量与对照均无明显差异;果实着色前KH2PO4处理显著增加了果实中蔗糖含量,但对葡萄糖和果糖含量无明显影响。幼果期和着色前喷施KH2PO4均显著提高了果实中蔗糖代谢酶活性。说明KH2PO4处理是通过全面提高果实中蔗糖代谢酶活性,起到提高库强作用,从而增加果实含糖量。