塑料日光温室CO2日变化规律及番茄CO2吸收利用研究

研究了塑料日光温室内ＣＯ２和番茄叶片光合速率日变化动态，以及ＣＯ２浓度、光强、温度与ＣＯ２吸收利用的关系。结果表明，塑料日光温室内ＣＯ２严重不足，中午前后降至２００×１０＾－６左右；番茄叶片光合速率日变化曲线呈双峰型，“午休”现象明显；２３℃、５００μｍｏｌ·ｍ＾－２ｓ＾－１自然条件下测定，ＣＯ２饱和点为１２００×１０＾－６，补偿点为１５０×１０＾－６，提高ＣＯ２浓度不仅提高了番茄叶片对ＣＯ２的吸     

高产香蕉平衡施肥技术研究

在肥力较高的老蕉园进行平衡施肥技术研究。结果表明：当第一造蕉氮肥用量达到1000 kg／hm^2以上及氮钾肥施肥比例N：K2O为1：1．15时，香蕉抽蕾提前，蕉果农艺性状及品质较好，产量达到52．5 t／hm^2的高产水平，获得较好的经济效益；随着施钾比例的增加，香蕉的营养生长受到一定的限制，农艺性状及品质均变差，产量及经济效益均有所下降。在土壤Mg／K=1．37的情况下增施镁肥，香蕉的营养生长受到一定影响，蕉果的农艺性状下降，但固形物与可溶糖含量提高，产量及经济效益明显降低；施用硫肥对香蕉的生长及产量影响不大，但由于增加了肥料成本而使经济效益有所下降。     

高产香蕉平衡施肥技术研究

在肥力较高的老蕉园进行平衡施肥技术研究。结果表明:当第一造蕉氮肥用量达到1000kg/hm2以上及氮钾肥施肥比例N K2O为1 1 15时,香蕉抽蕾提前,蕉果农艺性状及品质较好,产量达到52 5t/hm2的高产水平,获得较好的经济效益;随着施钾比例的增加,香蕉的营养生长受到一定的限制,农艺性状及品质均变差,产量及经济效益均有所下降。在土壤Mg/K=1 37的情况下增施镁肥,香蕉的营养生长受到一定影响,蕉果的农艺性状下降,但固形物与可溶糖含量提高,产量及经济效益明显降低;施用硫肥对香蕉的生长及产量影响不大,但由于增加了肥料成本而使经济效益有所下降。     

沙地衬膜水稻施肥效应与技术研究

沙地衬膜水稻采用无土栽培原理，施肥以化肥为主。适宜的N肥能显著促进沙地衬膜水稻营养体的生长．P肥则对水稻后期籽粒灌浆结实有明显效应。N、P配施较单施N、P处理籽粒产量和蛋白质含量有显著提高。在本试验条件下．沙地衬膜水稻栽培中。纯N最适施用量为144．7kg／km^2，最佳N、P配比为1：0．502．以使籽粒产量、蛋白质含量、单位面积蛋白质产量均表现较高。根据沙土特点和水稻生长发育规律，衬膜水稻施肥应坚持少量多次的原则，N肥分4次施入。P肥基施为主，K肥少量追施。另须基施Si等微肥。基肥采取沟深施。追肥撒施，采取前促、中控、后补的原则，主攻分蘖肥和穗粒肥。     

赤红壤旱坡地玉米测土施肥技术研究

用东莞桥头和广州石牌的大田试验数据。配制每造玉米Ｎ、Ｐ、Ｋ肥需求量的Ｓｔａｎｆｏｒｄ经验公式，由目标产量与特定地块的肥力算出玉米配方肥的Ｎ、Ｐ、Ｋ组分量。     

蔬菜日光温室增施二氧化碳气体

对日光温室内的蔬菜施用二氧化碳气体，可以使作物提高产量，减少病害，改善品质。介绍了增产机理，国内现有制所方法及使用等技术。     

水稻抛秧栽培不同施肥技术对产量的影响

不同的施肥技术对抛秧栽培的水稻产量有一定的影响,早稻施用蘖肥会因前期施肥比例过大,促进水稻的分蘖生长,使分蘖过多,中、后期因营养不足有效穗反而少,影响水稻产量;施好施足穗肥,能促进水稻的生殖生长,有利于碳水化合物的形成和积累,使有效穗、穗粒数和结实率增加,提高产量。晚稻因气温高,养分释放快,在注重对穗肥施用的同时,也应适当注意蘖肥的施用。     

黄花菜配方施肥技术研究

通过对黄花菜盆栽砂培试验、田间正交和氮磷肥单因素试验,研究了黄花菜配方施肥技术。结果是:黄花菜对N∶P2O5∶K2O三要素的最佳比例为2∶1∶2;对N、P、K三要素的总量以每亩40kg为宜(包括土壤供给量)。对不同肥力的土壤,每亩施用量的计算公式是:土壤中黄花菜可利用速效养分含量-每亩土壤速效性养分含量×黄花菜根系实际占用营养面积/栽培面积;在试验土壤条件下,要求施入N素9.5~1 3.5kg,P2O56.6~8.4kg;N、P单独施用,应酌量增加;N、P配合施用应适当减少;最佳的施肥时期是三月下旬一次施入。     

有机废弃物生物发酵法CO2施肥对大棚草莓的效果

试验结果表明,在塑料大棚中有机废弃物生物发酵法产生的CO2气体能在较长的一段时间内稳定在较高的水平,从而促进大棚草莓植株生长和发育,提早上市期,提高草莓的产量、品质。应用该CO2施肥技术后,草莓果实口感好,Vc含量提高11.25 mg.100 g-1,可溶性固形物和可溶性糖分别提高1.0和2.06个百分点,有机酸含量降低了0.10个百分点,硝酸盐含量下降了126.45μg.g-1。平均单果重比对照增加14.32 g,约提高67%,每公顷产量提高29.9%,增产、增效明显。     

增施CO2气肥对温室流场影响的数值模拟及验证

CO2气体是温室作物光合作用的重要原料之一。为掌握温室CO2气肥增施性能,以温室CO2气肥增施为研究对象,采用计算流体力学（computational fluid dynamics,CFD）技术建立二维紊流数值计算模型。基于FLUENT软件,结合SIMPLE算法,采用有孔介质模型、模型、离心坐标（discrete ordinates,DO）模型,添加组分传输模型,对气肥喷射高度、气肥增施流量等因素对CO2增施性能进行数值模拟,得到温室内CO2浓度变化和分布规律。研究结果表明：气肥增施过程对作物区的温度场影响较小,温室的作物区域最大温度与最小温度差值不超过0.5℃,作物区域的气流流场以及温度场分布较为均匀;由于CO2的沉积效应,温室下部区域的CO2浓度相对较高;气肥喷射高度越高,CO2扩散的范围越大,沉积在作物区的CO2相对越少,CO2的浓度也相对较低;气肥增施流量越大,作物区域的CO2浓度上升越快。试验结果表明,CO2浓度模拟值与试验值差异不大于5 %,模拟结果与试验结果较吻合,证明了模型的正确性。该研究对掌握温室CO2气肥增施性能的流场变化规律,开展温室气肥增施装备的优化设计具有一定的参考价值。     

CO2加富处理甜瓜幼苗光合特性的研究

以甜瓜幼苗为试材,研究不同浓度CO2对其光合特性的影响.结果表明与对照相比,经800,1000,1200,1400 μL/L加富的甜瓜幼苗的最大净光合速率的增幅分别为39.59%、70.52%、80.64%和131.21%.蒸腾速率分别下降12.16%、27.18%、37.34%和54.65%,同时叶气温差也呈上升趋势.胞间CO2浓度上升12.04%～14.25%.高浓度CO2在降低甜瓜幼苗光补偿点的同时,还使光饱和点升高.甜瓜幼苗CO2加富的适宜浓度为1200 μL/L左右.     

Effects of atmospheric CO2 enrichment on CO2 exchange rates of beech stands in small model ecosystems

CO₂ enrichment experiments were performed during two vegetation periods on young beech stands in four closed mini-greenhouses. The houses were climatized according to the outside microclimate (±0,5 °C,±15 % rel. air humidity, wind speed approximately to outside in the range of 0.5 – 2.5 m s^?1, max. 17 % PAR reduction). The model ecosystems — consisting of 36 young beech (2.5 yr-old) in a soil block of 0.38 m³ and an air volume of 0.64 m³ — were exposed to CO₂ concentrations of the unchanged ambient air (350±34 ppmv, control) and of 700 ppmv (698±10 ppmv). Plant growth parameters were measured non distructively and at the end of the 1^st season samples were taken for weighing the phytomass. CO₂ gas exchange of the stands taken as a whole were continuously measured with two entire mini-greenhouses and, in addition, a compact mini-cuvette system (CMS 400, Walz) was used for measuring dark respiration and CO₂ net assimilation rates of single leaves in both stands. Under the influence of the additional CO₂ supply stem diameter (2 cm above the first lateral roots) was increased by 13.5 %, stem height by 27.4 %, and the number of leaves/tree by 33 % at the end of the 2^nd season. The number of buds was not significantly different and the effect on mean area per leaf was insignificant. Leaf area index was by 1.4 units greater. All dry weights of the main organs were increased after the 1^st season: leaf 60 %, stem 34 %, bud 54 %. Roots <2 mm φ weighed 1.5-fold more and roots > 2 mm φ 1.7-fold more under elevated CO₂. CO₂ gas exchange of two systems was measured. Whole system CO₂ losses during night as well as photosynthetic CO₂ gains during days were greater at 700 ppmv than in the control system. However, if one balances CO₂ gains with CO₂ losses over a period of five days in August both model-ecosystems taken as a whole were sinks for CO₂. During this selected time period of 5 days at the peak of the season the beech stand at 350 ppmv was the greater sink. At 350 ppmv CO₂ (control) the average leaf respiration for 20 °C amounted to 0.31±0.18 and at 700 ppmv to 0.57± 0.42 μmol CO₂ m^?2 s^?1 (n=35/40, t=3.48, α < 0.05), and correlated positively with leaf temperature. At light saturation the mean net assimilation rate was 4.48 μmol m^?2 (leaf area) s^?1 in the control and 6.21 μmol m^?2 s^?1 at the high CO₂ concentration corresponding with an enhancement factor of 1.39 for the selected time period. Results from the whole stand and from single leaf measurements are compared by means of mathematical modelling procedures in order to quantify CO₂ enrichment effects on beech model ecosystems.     

稻田CO2排放对大气CO2浓度升高的响应

利用FACE (free-air carbon dioxide enrichment)平台,采用静态暗箱-气相色谱法,研究了大气CO2浓度升高对稻田土壤CO2通过土壤-大气(土气)和植被-大气(植气)界面排放的影响.在整个水稻生长季中,土气界面CO2排放通量与土壤表面水层深度指数负相关,且在中期烤田和收获前排水阶段出现较大值;而植气界面CO2排放通量与根系生物量的变化趋势基本一致.在低氮(N 125 kg/hm2)和常氮(N 250 kg/hm2)水平上,高浓度CO2(对照大气CO2浓度+200 μmol/mol)有提高水稻生物量、降低土气和植气界面CO2累积排放量的趋势.在水稻的拔节、抽穗和成熟期,较高的施氮量显著增加水稻地上部分生物量,促进植气界面CO2的排放.研究结果表明,未来大气CO2浓度升高的环境下,稻田生态系统有增加CO2的固定(增加水稻生物量),减少CO2的排放(土气和植气界面CO2的排放)的趋势,可能发挥着碳汇的作用.     

植物富集~(13)C标记技术的初步研究

<正>稳定同位素13C技术已被广泛用于研究土壤有机碳的周转[1-3]。13C技术可分为自然标记和人工标记两种[4-5]。13C自然标记方法研究土壤碳周转一般用于田间原位试验,要求有C3和C4植物的更替,且要有准确的更替时间。而室内培育实验利用这一方法则需加入较高的外源碳才能使δ13C值有较明     

An empirical method of measuring CO2 recycling by isotopic enrichment of respired CO2

An empirical method to measure respiratory CO₂ recycling using a fast growing agricultural cover crop as a model system was tested and compared with a theoretical method which uses a variation of the Keeling plot. Both methods gave values which were high and similar to each other. The theoretical method gave a value of respiratory based CO₂ recycling of 0.41, while the empirical method gave a value of 0.49. Therefore close to half of the respired CO₂ is refixed during daytime photosynthesis in this densely planted cover crop. Refixation of respired CO₂ during the day should lead to an isotopic enrichment of the remaining respired CO₂ leaving the canopy of the cover crop. Therefore, calculations of gross respiration and photosynthesis using isotopic mass balance equations that do not take this isotopic fractionation into account could be in error. We tested this premise by using isotopic mass balance equations to estimate average gross photosynthesis and respiration in this cover crop under two scenarios: (1) no recycling and (2) recycling of respired CO₂. Values of gross photosynthesis and respiration were unrealistically low when it was assumed that no recycling occurs. On the other hand, realistic values similar to previous publications were observed when recycling was taken into account.     

灌溉方式和秸秆还田对设施番茄田CO2排放的影响

中国北方下沉式设施菜田表层土壤缺失,以及高温高湿的环境条件,导致耕层土壤有机质含量低、矿化快。如何减缓土壤有机质矿化,是该文所关注的焦点问题。该研究采用二因素试验设计,主因素为灌溉方式（传统畦灌施肥、滴灌施肥）,副因素为秸秆（含C量为0、3 500 kg/hm2）。测定了48 h内每3 h的CO2排放通量,以及全生育期CO2日排放通量、土壤温度。结果表明：1）08:00−09:00测定的土壤CO2排放通量与CO2日均排放通量不存在显著差异,二者呈极显著线性正相关关系,其决定系数为0.987;而其他时段测定值与日均值均存在显著差异。2）与传统畦灌相比,无论是否添加秸秆,滴灌处理均显著降低了CO2累积排放量。3）CO2排放高峰出现在定植后8～15 d,随后逐渐降低并趋于平稳;定植后40 d内能检测到处理间CO2日排放通量的差异,此后处理间差异不显著。4）CO2累积排放通量和土壤积温呈显著正相关关系。综上所述,滴灌施肥栽培体系可显著降低土壤CO2排放量,有利于设施菜田土壤有机质的积累。     

Atmospheric CO2 enrichment and plant dry matter content

Fresh and dry plant weights were measured throughout a number of different CO₂ enrichment experiments with six terrestrial plants and two aquatic species. Similar data were also extracted from the literature for 18 additional plants. In general, CO₂ enrichment had little effect on plant percentage dry matter content, except under conditions conducive to starch accumulation in leaves, and then it caused an increase in percentage dry matter content.     

Forest responses to CO2 enrichment and climate warming

Two of the major uncertainties in forecasting future terrestrial sources and sinks of CO₂ are the CO₂-enhanced growth response of forests and soil warming effects on net CO₂ efflux from forests. Carbon dioxide enrichment of tree seedlings over time periods less than 1 yr has generally resulted in enhanced rates of photosynthesis, decreased respiration, and increased growth, with minor increases in leaf area and small changes in C allocation. Exposure of woody species to elevated CO₂ over several years has shown that high rates of photosynthesis may be sustained, but net C accumulation may not necessarily increase if CO₂ release from soil respiration increases. The impact of the 25% rise in atmospheric CO₂ with industrialization has been examined in tree ring chronologies from a range of species and locations. In contrast to the seedling tree results, there is no convincing evidence for CO₂-enhanced stem growth of mature trees during the last several decades. However, if mature trees show a preferential root growth response to CO₂ enrichment, the gain in root mass for an oak-hickory forest in eastern Tennessee is estimated to be only 9% over the last 40 years. Root data bases are inadequate for detecting such an effect. A very small shift in ecosystem nutrients from soil to vegetation could support CO₂-enhanced growth. Climate warming and the accompanying increase in mean soil temperature could have a greater effect than CO₂ enrichment on terrestrial sources and sinks of CO₂. Soil respiration and N mineralization have been shown to increase with soil temperature. If plant growth increases with increased N availability, and more C is fixed in growth than is released by soil respiration, then a negative feedback on climate warming will occur. If warming results in a net increase in CO₂ efflux from forests, then a positive feedback will follow. A 2 to 4°C increase in soil temperature could increase CO₂ efflux from soil by 15 to 32% in eastern deciduous forests. Quantifying C budget responses of forests to future global change scenarios will be speculative until mature tree responses to CO₂ enrichment and the effects of temperature on terrestrial sources and sinks of CO₂ can be determined.