Microbial recolonization and suppression of Rhizoctonia solani in a bedding-plant potting mix amended with recycled mix before aerated-steam treatment

Summary Some South Australian bedding-plant nurseries add recycled potting mix to fresh potting mix before aerated-steam treatment in an attempt to decrease fungal root diseases. To test the hypothesis that this addition of recycled potting mix affects microbial colonization and, consequently, the disease-suppressiveness of mixes treated with aerated steam, recycled potting mix was added to or withheld from fresh potting mix. The mixes were then treated with aerated steam at 60°C for 35 min or not treated. Their recolonization by actinomycetes, heat-resistant organisms, pseudomonads, and fungi was followed for 25 days. The addition of recycled potting mix frequently increased the numbers of actinomycetes and heat-resistant microbes recovered from the mixes, whether treated with steam or not, but decreased the numbers of aerobic bacteria. Fungal populations were rarely influenced by the addition of recycled potting mix. Pseudomonad populations dropped to undetectable levels after the aerated-steam treatment and failed to reach levels comparable to those in treatments without steam during the next 25 days. Organisms from each group were tested for in vitro antagonism to Rhizoctonia solani Kühn (AG-8). The proportion of inhibitory organisms varied with the microbial group, the mix treatment, and the time since mix treatment. Where aerated-steam treatment was applied, the addition of recycled potting mix rarely affected the development of Rhizoctonia disease symptoms on seedlings of Celosia argentea. The potential for improving the suppressiveness of aerated-steam-treated nursery mixes via microbial inoculation is discussed.     

Effects of nutrition systems and irrigation programs on tomato in soilless culture

A research has been carried out to determine the effects of nutrition systems and irrigation programs on soilless grown tomato plants under polyethylene covered unheated greenhouse conditions. Two nutrition systems (open and closed) and three irrigation programs (high, medium and low) based on integrated indoor solar radiation triggering thresholds (1 MJ m⁻² [0.4 mm], 2 MJ m⁻² [0.8 mm] and 4 MJ m⁻² [1.6 mm]) in both nutrition systems have been tested. Applied and discharged nutrient solution, evapotranspiration, total and marketable yield have been measured and water use efficiency has been calculated. The highest total yield has been obtained from the open system with respectively 11% and 7.2% increases in autumn and spring. Applied nutrient solution volume and seasonal ET have been modified between 47.8-180.4 l plant⁻¹ and 41.7-145.5 l plant⁻¹ respectively during both growing seasons. As average of two growing seasons, respectively 826.5 and 330.6 m³ ha⁻¹ nutrient solutions have been discharged from the greenhouse in the open and closed systems. WUE of treatments varied between 33-55 kg m⁻³ in autumn and 26-35 kg m⁻³ in spring. Highest WUE values have been determined in 4 MJ m⁻² and in the closed system in both growing seasons. Results showed that the closed system and infrequent irrigations increased water use efficiency while decreasing yield and discharged nutrient solution.     

有机生态型无土栽培辣椒品种比较试验

选用6个辣椒品种（陇椒2号、陇椒3号、陇椒5号、甘科5号、酒椒3号,hxuty）进行有机生态型无土栽培品种比较试验。结果表明,陇椒2号、陇椒3号、陇椒5号、甘科5号、酒椒3号和hxu-ty的生育期无差异,但酒椒3号的株高、果长、果肩宽较对照陇椒2号依次降低4cm、缩短0．04cm、变窄0．1mm,单果质量、产量较对照陇椒2号增加1．5g和4.3％。综合评判酒椒3号可作为有机生态型无土栽培辣椒品种种植。     

Wetting agent effect on physical properties of new and reused rockwool and coconut coir waste

Wettability of growing medium in horticulture is an important practical factor of this industry. With a proper choice and a right application, wetting agent in the nutrient solution would improve wettability and some other physical properties of growing media. The aim of this study was to evaluate the effects on some physical properties of new and reused rockwool and coconut coir dust substrates with different doses of wetting agent (2, 10, 20, 100, 200, 1000, 2000, 10,000 and 20,000 mg L⁻¹) applied to the nutrient solution and their effects measured by using bioassays. The wetting agent was ether poly-ethylene-glycol nonil-phenol with 20% (w/v) as an active ingredient of a non-ionic surfactant. Bioassay results showed differences among species. For this, the method can be suggested as a good tool to be utilized through fertigation in soilless crops; however, other studies should be proposed for each species in particular. Except to the 2 mg L⁻¹ wetting agent content in reused coir waste, the total water-holding capacity increased with the wetting agent. With 2 mg L⁻¹ wetting agent content there was an important and significant increase the easily available water (over 600%) in both substrates (including the reused ones), while higher doses show no significant differences. The effect of adjuvants added through fertigation is directly dependant on the substrate type evaluated. The substrate reutilized after one crop, reduces the air capacity and increases the easily available water and total water-holding capacity. 2 mg L⁻¹ is the wetting agent concentration more adequate in coir waste and rockwool.     

盆栽草莓基质筛选试验初报

试验目的为筛选出最佳盆栽无土草莓基质,适应盆栽草莓工厂化生产的技术体系,为相关园艺植物无土栽培技术研究和工厂化生产提供实践和理论依据。用河沙、珍珠岩、煤渣和草炭不同比例的11种组合为处理,试种品种为丰香,进行单因素随机区组试验,研究不同基质配方对盆栽草莓的生长结果影响。结果表明不同处理的生长结果指标差异显著。利用加权平均数的评价,筛选出三个较好的盆栽草莓基质配方:草炭:煤渣(体积比1:1),珍珠岩:煤渣(1:1)和珍珠岩:河沙:煤渣(1:1:1)。     

人工复合基质对微型盆栽月季生长发育影响的研究

比较系统地研究了7种不同无土人工复合基质对微型盆栽月季(Rosa hybrida ‘Miniature Pink’)生长与发育的影响。结果表明，100％泥炭，70％泥炭 30％珍珠岩，70％珍珠岩 30％泥炭这3种基质比较理想，其对微型盆栽月季的株高、枝叶鲜样质量及干样质量、叶面积、平均根长、最长根长、根鲜样质量及干样质量、现蕾日期、开花日期、花朵直径等均表现为显著的促进作用；微型盆栽月季无土基质的优化物理性状为：容重O．12～0．19g／cm^3，比重1．6～1．9g／cm^3，含水量(风干基质)6％～16％，总孔隙度90％～94％。     

无土育苗对欧洲报春幼苗素质的影响

通过研究5种不同育苗基质和育苗方式对幼苗苗质的影响,试验结果表明:在种子萌发期间,泥炭:椰糠:珍珠岩(1:1:1)和农友育苗基质的出苗率较好。在真叶露出后,除了以上两种表现良好的基质外,蘑菇渣 珍珠岩(1:1)基质组合的幼苗比椰糠 珍珠岩(1:1)基质组合的幼苗又表现出了较强的生长势。     

牡丹无土盆栽研究现状与展望

综述了国内外牡丹无土盆栽研究现状,指出了牡丹无土盆栽存在的主要问题,并对牡丹无土盆栽的前景进行了展望。     

无土栽培网纹甜瓜营养液配方的筛选

对无土重茬种植的网纹甜瓜浇灌不同配方的营养液,以观察植株的生长情况和抵抗病害的情况。结果表明,配方Ⅰ:Ca(NO3)20.83 g/L、KNO30.6 g/L、NH4H2PO40.15 g/L、MgSO4.7H2O 0.37 g/L、EDTA-Fe 16 mg/L为最佳营养液配方。该营养液对植株生长有明显的促进作用,重茬病很少发生,植株存活率达92.5%,坐果率达100%,平均单果质量1.13 kg,具有良好的应用前景。     

基质与氮磷钾比例对蝴蝶兰(Phalaenopsis hybridium)生长发育的影响

试验于温室进行,利用正交试验及灰色关联度分析（综合评价指数）,研究了四种代用基质与施肥方法与蝴蝶兰生长发育的影响。结果表明,蕾期施肥和基质类型是影响蝴蝶兰开花数量的主要因子。灰色关联度最高,（Ri=0.69337)的处理组合是水藓基质施肥200（N,mg/L),N-P(P2O5)-K(K2O)=15-15-15,现蕾后以磷钾肥加微量元素处理,其次是锯末＋沙,施肥200（N,mg/L),N-P-K=20-10-10,现蕾前用磷钾肥加微肥处理;三是花生壳＋沙,施肥量100（mg/L),N-P-K=15-15,15,沙＋KD－1型高吸水树脂基质的Ri值最低。