蔬菜无土栽培营养液管理常见问题分析

近年来,无土栽培在国内外蔬菜设施栽培中发展迅速,在克服连作障碍,拓展蔬菜种植领域,抵御不良环境,生产无公害蔬菜等方面,具有常规土壤栽培难以比拟的优越性.但由于无土栽培的核心技术营养液的配制与管理,受栽培环境,作物种类,生产者技术水平等诸因子的制约,常出现一些问题,在一定程度上限制了无土栽培的推广和应用.在此,就营养液管理中常出现的相关问题作以简要分析.     

小型西瓜有机生态型无土栽培技术

有机生态型无土栽培技术是指不用天然土壤而使用基质,不用传统的营养液灌溉作物根系,而使用有机固态肥并直接用清水灌溉作物的一种无土栽培新技术。由于它具有投资省、成本低、用工少、易操作和高产、优质等特点,能生产出无公害产品,并可以吊蔓加大密度,提高产量和品质,特别适合小型礼品西瓜栽培,近几年在我国得到了迅猛发展。2004年3～6月在温州市农业高新技术示范区温室,采用该模式成功试种了1．2hm^2小型西瓜,取得了良好的效果。现将栽培技术介绍如下：     

波兰的草莓生产和育种现状

波兰受波罗的海的影响,属于湿润的海洋性气候,非常适合草莓种植。经过几十年的努力,波兰的小浆果类特别是草莓的种植面积和产量逐年上升,2002年草莓总产量达到20.5万吨,栽培面积为6.39万公顷,种植面积和产量均居世界前列。目前主栽品种为“森加·森加那”、“鲍拉”、“杜卡特”等。生产的草莓83%用于冷冻出口和加工,国内市场鲜食占12%,出口鲜草莓占5%,主要向美国、加拿大和德国出口。最近几年,波兰除了加强加工草莓育种之外,在鲜食草莓育种方面也取得了一定的成绩。1育种现状波兰草莓育种的主要目标是培育适应波兰气候条件,尤其是耐冬季低…     

越夏花椰菜两种常见细菌病害的诊断与综合防治

花椰菜是福建省屏南县种植业结构调整后的主要传统特色优势农作物，常年种植面积稳定在4000hm^2。屏南县的花椰菜生产在宁德市乃至福建省都是领先发展的，有“新田王”（福建省名牌农产品）、“锦源丰”（绿色食品）两个品牌。越夏花椰菜播种期为3月中旬～7月下旬，幼苗四叶一心时定植，定植后60～70d（天）采收。近年来细菌性黑斑病、细菌性黑腐病严重影响花椰菜的产量和品质。所以，要继续做大、做强花椰菜产业，必须了解、熟悉、掌握细菌性黑斑病、细菌性黑腐病的田间诊断、发病原因与综合防治措施。现将其病害诊断、发病原因与防治措施介绍如下。     

黄瓜椰糠栽培营养液的适宜浓度探索

为了探索黄瓜椰糠栽培中适宜的流出液EC值指标,根据流出液EC值的高低来调节灌溉液浓度,实现肥料的合理施用。试验设置了1.8、2.2和2.6 mS·cm^-1三个流出液EC值指标,灌溉液浓度的“增减量(/g·L^-1)=(EC值设定值-EC值测定值)×流出率/%”。此模型不仅考虑了EC值设定值与测定值的差异,而且考虑了流出率因素。通过“配液浓度=在用浓度+增减量”,对灌溉液浓度进行连续调控。结果显示,伴随灌溉液浓度的升高与降低,流出液EC值围绕设定值上下波动,基本实现了稳定。流出液中氮、磷、钾、钙、镁元素的含量与EC值设定值正相关,反映了肥料供应水平的高低。当流出液EC值设定在2.2和2.6 mS·cm^-1时,黄瓜的产量差异不显著,却又都比EC值在1.8 mS·cm^-1设定值时显著增加。所以,2.2~2.6 mS·cm^-1可作为黄瓜椰糠栽培适宜的流出液EC值控制区间。     

Nutrient uptake of pepino plants in soilless cultivation

Summary

This study addresses vegetative growth and the uptake of nutrients and their accumulation in the vegetative and reproductive tissues of pepino (Solanum muricatum Ait.). The study was conducted in soilless plastic house conditions, with a planting density equivalent to 25.000 plants ha^–1 during two seasons (1997–98 and 1998–99). The plants were sampled, fractionated into leaves, stems, fruits and roots, then dried and weighed and the macronutrient content was analysed every 30.d for 300.d after transplanting. The yield obtained was 2.kg of fruit per plant, which is 30% of the total dry weight. The relative growth rate (RGR) ranged from 0.0028 to 0.0451.d^–1. The highest N, K, Ca and Mg concentrations were recorded in the leaves, and the highest P concentration in the roots. The nutrient accumulation of this yield was 10.64, 1.12, 16.06, 10.0 and 1.58.g of N, P, K, Ca and Mg per plant respectively. The highest accumulation of all nutrients was found in the leaves. The nutrient with the highest specificuptake rate was K, which ranged from 0.0037 to 0.0838.g g^–1 d^–1.     

Closed cycle subirrigation with low concentration nutrient solution can be used for soilless tomato production in saline conditions

Closed cycle soilless techniques can be adopted to minimize water and fertilizer losses in greenhouse cultivation. There is a general lack of information regarding the soilless cultivation of vegetables with closed cycle subirrigation techniques, specifically when using saline water. In this study, a trough bench subirrigation system (SUB), with two fertilizer concentrations (“100%”, containing 9.8 mol m⁻³ N-NO₃, 1.6 mol m⁻³ P-H₂PO₄, 8.7 mol m⁻³ K⁺, 2.8 mol m⁻³ Ca⁺, 1.8 mol m⁻³ Mg⁺, 4 mol m⁻³ S-SO₄, and “70%”, containing 70% of the macronutrient concentration) in the nutrient solution (NS), was compared with open cycle drip-irrigation (DRIP with “100%” NS). For all the three treatments, NS was prepared using rain water (0.05 dS m⁻¹) and adding NaCl (1 g L⁻¹), in order to simulate moderate saline irrigation water. The effect of the treatments on tomato (Solanum lycopersicum L.) plant growth, yield, fruit quality, water use efficiency (WUE) and fertilizer consumption was evaluated. Substrate and recirculating NS composition were also studied. Subirrigation, regardless of NS concentration, reduced plant height (by 30 cm), leaf area (by 1411 cm²), total fresh and dry weight (by 429 and 48.5 g plant⁻¹, respectively) but not dry matter percentage of the whole plant, with respect to DRIP. Yield was reduced when plants were subirrigated with the higher concentrated NS, but no differences with open cycle DRIP were recorded when the lower NS concentration was used in SUB. Fruit quality was not affected by irrigation system or NS concentration. The higher WUE was obtained with subirrigation. NaCl accumulated similarly over the crop cycle in recirculating NS of both SUB treatments and in growing substrates of all the three treatments. Higher salt concentration was found in subirrigated substrates, in particular in the upper part of the substrate profile. Fertilizers accumulated in the subirrigated substrates when the higher NS concentration was used, but not when the NS concentration was reduced by 30%. The results of this study indicate that tomato can be grown successfully in a closed cycle subirrigation system, using saline water, by reducing the fertilizer NS concentration normally used with traditional open cycle systems.     

Crop production in recirculating nutrient solution

The development of a low capital cost technique for crop production in recirculating nutrient solution is described with special reference to greenhouse tomato production. Tomato trials in heated glasshouses are reported and attention is drawn to the decline in root growth which began in late April and ceased in early June. It is suggested that this “May check” may be related to time of year and not to plant age.     

Accumulation of phytotoxic organic acids in reused nutrient solution during hydroponic cultivation of lettuce (Lactuca sativa L.)

Proper nutrient solution management in the root zone is the first consideration for the adoption of a closed hydroponic system. Plant roots often exude numerous organic acids, which are known to inhibit growth. To investigate the accumulation of these phytotoxic organic acids as root exudates, lettuce (Lactuca sativa L.) was hydroponically grown in reused nutrient solution. Organic acids were extracted with diethyl ether from the reused nutrient solutions (RNS), root residues, and activated charcoal (AC) then quantified by GC/MS. Five individual organic acids were identified from the root residues and seven from the reused nutrient solutions. After 90 days of lettuce cultivation, in the treated AC in 3RNS, benzoic, phenylacetic, cinnamic, p-hydroxybenzoic, lauric, phthalic, vanillic, palmitic, and stearic acids were identified. In contrast, little or no organic acids were detected in the 3RNS treated with AC (3RNS/AC). Artificially applied pure organic acids ranging from 25 to 200 μM inhibited lettuce growth in a concentration-dependent manner. Lettuce growth was also greatly reduced in the nutrient solutions containing a externally applied, simulated mixture of the organic acids as in the 3RNS. Lettuce growth was not inhibited following the addition of AC (2.5 g/L) to the nutrient solution containing the mixture of organic acids. Our results demonstrated that organic acids were accumulated in reused nutrient solutions and were phytotoxic to lettuce growth. Also, this study showed that the addition of AC reduces the phytotoxic effects by eliminating the organic acids.     

Nutrient solution effects on the development and yield of Anthurium andreanum Lind. in tropical soilless conditions

The fertilization of anthurium grown in soilless culture in tropical countries is often empirically based. The methods used generally lead the grower to overestimate plant needs and to apply excessive quantities of nutrients. Mineral elements, and thus money, are wasted and there is a risk of pollution of groundwater and watercourses. In order to improve our knowledge of plant requirements, we measured, over 2 1/2 years, the growth and yield of anthurium plants receiving nutrient solutions with different total nitrogen, potassium and calcium concentrations and different NH₄⁺/NO₃⁻ ratios. Mineral analyses of plant parts, of nutrient, leachate and substrate solutions and of the solid substrate were carried out throughout plant development. Plants receiving 4.5 mmol N/l and 1.6 mmol K/l in the nutrient solution had significantly slower growth and lower yield compared to those receiving 8.9 mmol N/l and 3.2 mmol K/l. For these latter N and K concentrations, a N–NH₄⁺/N–NO₃⁻ ratio of 0.37 and a calcium concentration of 1.15 mmol/l gave better plant growth, development and yield than a ratio of 0.24 and a calcium concentration of 2.25 mmol/l. Applying the nutrient solution containing 8.9 mmol N/l and 3.2 mmol K/l with a N–NH₄⁺/N–NO₃⁻ ratio of 0.37 resulted in a shorter vegetative period and more and larger flower production. The calculated mineral balances of the crop showed that more than 60% of the supplied nutrients were lost in the leachate. Suitable nutrient solutions are proposed in order to match plant absorption at different crop growth stages. The volume of nutrient solution supplied can be reduced to limit the amount of leachate, but as water demand is high, there must be at least 30% of leaching to avoid salt accumulation in the substrate. Adjusting the nutrient solution volume and composition to match plant requirements is the first step for flower yield improvement, fertilizer efficiency and reduction of pollution.     

平菇营养液配方的研究

本试验是通过平板试验，在培养基中添加VB1，复合肥(N、P、K)、NPP、乙烯利，通过四因素三水平的正交试验，旨在选择一种最佳组合。试验结果表明VB1(0.002%)，N.P.K(0.05%)、NAA(5×10-6)、乙烯利(500×10-6)，此种配比最适合平菇菌丝的生长。     

不同营养液配方对阳台水培黄瓜的影响

以‘戴多星’黄瓜为试材,系统研究了7种不同营养液配方T1~T7对阳台水培黄瓜生长的影响,通过测定黄瓜的株高、茎粗、SPAD值、产量、可溶性固形物含量和维生素C等指标,初步筛选和评价出适合阳台水培黄瓜的最佳营养液配方。结果表明:使用T7营养液配方水培黄瓜可以显著提高叶面积,达到429.25 cm2;SPAD值增至47.08;结瓜数14个、单瓜质量65.08 g和单株产量889.34 g、维生素C含量145.68 mg·kg-1和可溶性固形物含量4.24%。与其他配方相比,T7增幅差异显著,可作为阳台上水培黄瓜的最佳营养液配方。     

Production and quality of greenhouse roses in recirculating nutrient systems

Greenhouse-grown rose plants were grown in either a non-recirculating (open) nutrient system, or a recirculating (closed) nutrient system with or without one of five amendments. Recirculation had no effect on harvest parameters during the first 8 weeks of the harvest period, but had a negative impact on stem length during the second 8 weeks, and on stem number and length when averaged over the entire harvest duration. Differences were not likely caused by changes in electrical conductivity or macro-nutrient concentrations of the nutrient solutions. Amendments to the recirculated solutions consisted of increased concentrations of Ca, B or Si, reduced pH, or use of an adsorbent resin to remove specific organic molecules. All amendments mitigated the negative effects of recirculation on at least two harvest parameters, but only during the second-half of the harvest period. With the exception of the intentional changes, mineral status of the nutrient solutions were similar in all recirculated treatments. Leaf chlorosis was observed in all recirculation treatments. It is likely that the reduction in rose quantity and quality in recirculation is caused by a combination of factors, some of which were ameliorated through the addition of specific amendments to the solution.     

Differential tolerance to iron deficiency of citrus rootstocks grown in nutrient solution

We studied the effects of Fe deficiency on physiological parameters of citrus rootstocks grown in nutrient solution. Three 4-week old rootstocks (‘Troyer’ citrange – Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf., Citrus taiwanica Tan. and Shim., and ‘Swingle’ citrumelo – Poncirus trifoliata (L.) Raf. × Citrus paradisi Macf.) were grown in nutrient solutions with 0, 5, 10, 15 and 20 μmol Fe dm⁻³. Calcium carbonate (1 g dm⁻³) was added to all solutions to mimic the natural conditions in calcareous soils. For each rootstock, shoot length, number of leaves, and root and shoot dry weights were measured at the end of experiment. Chlorophyll concentration was estimated using a portable SPAD-502 meter calibrated for each rootstock. The amount of nutrients (P, K, Mg, Ca, Fe, Zn, Mn, and Cu) was determined in shoots. Chlorophyll fluorescence parameters (F₀: basal fluorescence; F_m: maximum fluorescence; F_v = F_m − F₀: variable fluorescence) were measured with a portable fluorimeter. ‘Troyer’ citrange rootstock was the most tolerant to Fe deficiency. These plants grew more and accumulated more chlorophyll and nutrients than the others in the presence of low levels of Fe (10 μmol Fe dm⁻³). ‘Swingle’ citrumelo plants needed 20 μmol Fe dm⁻³ in the nutrient solution to secure adequate growth. ‘Taiwanica’ orange rootstock had an intermediate behaviour, but could be distinguished from ‘Troyer’ citrange based on fluorescence parameters, since there was a variation in the basal fluorescence in the former, whereas in ‘Troyer’ citrange the basal fluorescence was not affected by the supply of Fe.