Hans-Peter Kläring's research while affiliated with Leibniz-Institute of Vegetable and Ornamental Crops and other places

Publications (71)

Article
Full-text available
Modern plant cultivars often possess superior growth characteristics, but within a limited range of environmental conditions. Due to climate change, crops will be exposed to distressing abiotic conditions more often in the future, out of which heat stress is used as example for this study. To support identification of tolerant germplasm and advance...
Article
Full-text available
Concepts of semi-closed greenhouses can be used to save energy, whereas their technical equipment often causes a decrease in the light received by the plants. Nevertheless, higher yields are achieved, which are presumably triggered by a higher CO2 concentration in the greenhouse and associated higher photosynthesis because of the technical cooling...
Article
Full-text available
In contrast to conducting measurements on single plants, canopy gas exchange monitored continuously and for large batches of plants can give high-value data for crop physiological models. To this end, a system including eight airtight greenhouse cabins with a ground area of 28.8 m2 and a volume of 107.8 m3 each was designed for measuring the CO2 an...
Article
Closed fertilisation systems improve the water use efficiency of greenhouse crop production, which reduces groundwater pollution considerably. However, the uptake ratio of water and the individual nutrients is not constant over the cultivation period of most crops. This may result in ion imbalances in the nutrient solution if the composition of the...
Article
Root exudation of organic carbon (C) is generally believed to be the cause of positive effects of root activity on nitrous oxide (N2O) emissions. We tested the effects of root exudation in an actual soil–plant system on N2O emissions while excluding most other potential factors. The C source/sink ratio in cucumber was changed by removing fruits to...
Conference Paper
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Die anstehenden Veränderungen im Energiesektor im Zuge der Abkehr von fossiler Energie hin zu den erneuerbaren Energien sind groß. Um auch zukünftig die Versorgungssicherheit zu gewährleisten, bilden Energiespeicher und energieeffiziente Maßnahmen zentrale Elemente dieser Veränderungen. Dies gilt sektorenübergreifend und für alle Wirtschaftszweige,...
Poster
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Ionenselektive Elektroden (ISE) werden meist in Laboren zur potentiometrischen Bestimmung der Aktivität eines bestimmten Ions in einer Lösung mit verschiedenen Ionen verwendet. Für die Pflanzenernährung relevante Elektroden sind unter anderem für NO3-, K+, Ca2+, Na+ und Cl—Ionen verfügbar. Der Einsatz von ISE in der gartenbaulichen Praxis scheitert...
Poster
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Im Rahmen eines mehrjährigen Verbundvorhabens wurden Möglichkeiten der Optimierung geschlossener Wasser- und Nährstoffkreisläufe für Gewächshauskulturen untersucht. Dazu ist eine Anlage zur ionenspezifischen Steuerung der Nährlösung entwickelt worden, bei der einerseits Modelle der Wasser- und Nährstoffaufnahme integriert wurden und andererseits di...
Poster
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Due to the fact that greenhouses need big amounts of energy (esp. for heating purposes in temperate zones), there is a growing interest on new technical systems to save energy and fossil resources. In this context, the inclusion of active solar thermal systems in greenhouses for energy harvesting and plant production represents an interesting solut...
Poster
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The use of ion-selective electrodes in closed irrigation systems is possible, but the environmental conditions must be adapted. Feeding the samples to the ISE-measuring system enables automated calibration and control of ISE. Also the lifetime of ISE is increased if these are not permanently in liquids. Changes in the ion concentrations of nutrient...
Poster
Full-text available
The permanent control of drain solution in closed nutrient cycle allows a suitable nutrient dosing. The frequent adaptation of the nutrient solution composition resulted in significant increase of the yield and a lower incidence of blossom-end-rot in tomatoes.
Article
The effect of suboptimal supply of nitrogen (N) and of replacing nitrate in the nutrient solution with ammonia on growth, yield, and nitrate concentration in green and red leaf lettuce was evaluated over two seasons (autumn and spring) using multiple regression analysis. The plants were grown in a greenhouse on a Nutrient Film Technique (NFT) syste...
Conference Paper
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Mit geschlossenen Düngungs-und Bewässerungssystemen können die Wassernutzungseffizienz von Gewächshauskulturen verbessert und Nährstoffausträge in die Umwelt verhindert werden. Allerdings ändert sich das Nährstoffaufnahmeverhalten im Kulturverlauf, zum Beispiel durch veränderte Klimabedingungen und zu unterschiedlichen Entwicklungsstadien. Dies kan...
Conference Paper
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Gegenwärtig liegt der Anteil der erneuerbaren Energieträger (z.B. Wind- und Sonnenenergie) bei der jährlichen Stromerzeugung in Deutschland bei etwa 35%. Bis zum Jahr 2030 will die Bundesregierung diesen Anteil auf 50% erhöhen. Andere EU-Staaten haben ähnlich Pläne. Prognosen zeigen, dass dies die Volatilität (Schwankung) der Stromerzeugung und -pr...
Conference Paper
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In Germany, the growing introduction of electricity generated from renewable energy creates variability on electricity tariffs. The present research is based on the idea of taking advantage of low electricity prices for supplemental illumination in greenhouse production. Due to the variation of electricity prices, also the application of the lighti...
Article
Decreasing the temperature in heated greenhouses significantly reduces heat costs and CO2 emissions. However, the thermophile cucumber is known to be very sensitive to low temperatures. In particular, fruit growth decreases considerably as temperature declines. Nevertheless, reports show that cucumber can be grown successfully at low night temperat...
Conference Paper
Full-text available
Im ELGEVOS-Verbund (bestehend aus IGZ, HU und Fraunhofer IWES) sollen Konzepte für Gewächshäuser entwickelt werden, die sich auf eine zunehmende Nutzung von erneuerbaren Energien einstellen (Ziel der Bundesregierung: 50 % bis 2030) und der damit einhergehenden Volatilität des Stromangebots bzw. der Strompreise begegnen. Die Lösungsansätze sollen de...
Article
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Carbon dioxide (CO2) enrichment is a common practice in greenhouses to increase crop yields up to 30%. Yet, reports on the effect on foliar phenolic compounds vary. We studied the effect on two red leaf lettuce cultivars, grown for 25days in growth chambers at CO2 concentrations of 200 or 1000ppm, with some plants exchanged between treatments after...
Article
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The contribution of carbon assimilation and allocation and of invertases to the stimulation of adventitious root formation in response to a dark pre-exposure of petunia cuttings was investigated, considering the rooting zone (stem base) and the shoot apex as competing sinks. Dark exposure had no effect on photosynthesis and dark respiration during...
Chapter
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Im ZINEG-Projekt wurden an mehreren Standorten Zukunftskonzepte für Unterglaskulturen entwickelt mit dem Ziel, den Energieverbrauch wesentlich zu senken und CO2-Emissionen zu reduzieren. An den Standorten Berlin, Hannover, Schifferstadt und Osnabrück entstanden Projekte mit unterschiedlichen Konzepten aber gleichgerichteter Zielsetzung. Die Pflanze...
Article
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Reduction of nitrogen application in crop production is desirable for ecological and health-related reasons. Interestingly, nitrogen deficiency can lead to enhanced concentrations of polyphenols in plants. The reason for this is still under discussion. The plants' response to low nitrogen concentration can interact with other factors, for example r...
Chapter
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Six years ago, four universities and five research institutes started the joint research project ZINEG. Their goal was to produce plants in greenhouses with minimal consumption of fossil energy. In a system oriented approach they combined process engineering and cultivation measures. At the IGZ, research focused on cultivation measures in order to...
Article
Temperature integration strategies are a method for decreasing the amount of energy consumed in greenhouse plant production. These strategies are based on the hypothesis that plants can accumulate carbohydrates such as soluble sugars and starch during periods when growth is limited by low temperature for later use when the temperature rises. Howeve...
Article
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Domesticated tomato (Solanum lycopersicum) is the most important horticultural crop worldwide. Low polymorphism at the DNA level conflicts with the wealth of morphological variation. Fruits vary widely in size, shape, and color. In contrast, genetic variation between the 16 wild relatives is tremendous. Several large seed banks provide tomato germp...
Article
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Background and aims: Many attempts have been made to avoid the commonly observed fluctuations in fruit initiation and fruit growth in crop plants, particularly in cucumber (Cucumis sativus). Weak sinks of the fruit have been assumed to result in low sink/source ratios for carbohydrates, which may inhibit photosynthesis. This study focuses on the e...
Article
We investigated the effect of low level photosynthetic photon flux density (PPFD; 43 - 230 µmol m(-2) s(-1)) on the major phenolic compounds of red leaf lettuce in three growth stages - before, during, and after head formation - using HPLC-DAD-ESI-MS(2) and evaluating via multiple regression analysis. Generally, the light-related increase of flavon...
Article
Tomato (Solanum lycopersicum cv. Kommeet) plants were either self-grafted, grafted onto the cold-sensitive cultivar Moneymaker or onto LA 1777, a cold-tolerant accession of Solanum habrochaites. Plants were grown at three different temperatures (T): optimal (19.4 °C), intermediate (17 °C), or low (14.6 °C). Grafting tomato ‘Kommeet’ onto LA 1777 in...
Article
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Cultivating lettuce in greenhouses at low temperatures improves its CO2-balance and may increase its content of flavonoid glycosides and phenolic acids. We cultivated 5weeks old red leaf lettuce seedlings at 20/15°C (day/night) or 12/7°C until plants reached comparable growth stages: small heads were harvested after 13 (warm) and 26 (cool)days, whi...
Data
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Für den Gemüsebau entwickelte geschlossene Gewächshäuser koppeln Solarenergie an Tagen mit hoher Einstrahlung aus, speichern diese und nutzen sie für die Heizung in kühlen und dunklen Perioden. Der optimale Betrieb dieser Gewächshäuser erfordert neue Ansätze für die Klimaregelung: Im Fall der Wärmeauskopplung bleibt die Lüftung geschlossen – Temper...
Article
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Applying transparent daytime screens in greenhouses in cool seasons reduces the amount of energy needed for heating, but also the solar radiation available for crops. This can reduce yield and product quality of leafy vegetables because of constrained photosynthesis and altered biosynthesis. To study this, we cultivated five-week old red leaf lettu...
Article
// Zeitschrift Gemüse - Das Magazin für den professionellen Gemüsebau (ISSN 0016-6286), 49(10), pp. 10-13 // Angesichts steigender Heizkosten und Umweltbelastungen durch Nutzung fossiler Brennstoffe bekommt der Einsatz von Energieschirmen in Gewächshäusern eine immer größere Bedeutung. Normalerweise werden Schirme nachts verwendet und bleiben tagsü...
Article
Recent studies propose the combination of electrical energy and plant production, in which often only radiation peaks were used for energy production. Then, the effect on plant growth is assumed to be negligible. However, photosynthesis is known to be a monotonically increasing function of radiation. We studied the response of tomato to constrainin...
Article
Available water and nutrient management models (fertigation models) simulate water and nutrients transport in soil, uptake by plants, partitioning between solid and liquid phases in soil, organic matter transformations, and mass balance of water, nutrients and salts in the soil root volume, as function of weather conditions and horticultural practi...
Article
Considering that adventitious root formation (ARF) relies on adequate supply of carbon, the objectives of this study were (I) to evaluate how CO2 assimilation contributes to the carbon balance of petunia cuttings and (II) to study the extent to which CO2 assimilation depends on the progress of ARF and environmental key factors. CO2 gas exchange and...
Article
In order to reduce heat energy consumption in greenhouse cucumber production, (transparent) screens may be used also during the day, particularly in the early growth phase when high temperatures are required to achieve rapid leaf area development. However, energy savings must be optimised against light reduction‐induced yield loss. For this reason,...
Article
Plants respond to many stress factors, including infections caused by root pathogens, with reductions in photosynthesis and growth. We studied the response of mature cucumber plants after a weak inoculation of the roots with Pythium aphanidermatum. The epidemiology of the disease was recorded using an indirect ELISA. Although mycelium was detected...
Conference Paper
Adventitious root formation (ARF) in Petunia cuttings could be enhanced by dark-cold incubation before planting and exposure to light. To support the hypothesis that nitrogen and carbon redistribution is involved, different nitrogen compounds and carbohydrates were monitored in fully developed leaves and the stem base of cuttings during dark exposu...
Article
Full-text available
Pythium aphanidermatum is the most wide-spread root patho-gen in greenhouse cucumber. Although environmental condi-tions are known to affect the disease severity and many in vitro studies have documented these effects, only few in vivo experiments have been conducted, mainly focusing on the effect of temperature. In the present study, the impact of...
Article
Atmospheric carbon dioxide (CO(2)) concentration is an environmental factor currently undergoing dramatic changes. The objective of the present study was to determine the effect of doubling the ambient CO(2) concentration on plant photochemistry as measured by photochemical quenching coefficient (qP), soluble sugars and volatiles in broccoli. Eleva...
Conference Paper
Nowadays a trend in soilless cultivation systems is toward re-circulating and re-use of nutrient solution to avoid nutrient losses and to protect the environment. The standard strategy is the application of a nutrient solution based on empirical recipes and frequent analyses of the nutrient concentration in the solution. New concepts to predict nut...
Article
Full-text available
A severe drawback in hydroponic production systems and irrigated field cultivation arises due to the risk of hypoxia, provoked by water logging in the root environment. The effects of hypoxia become temporarily visible when plants are irreversibly damaged. For this reason, non-invasive methods are required for detecting hypoxia in good time. In fiv...
Conference Paper
Tomato fruits are a rich source of bioactive compounds, such as carotenoids. In order to increase health-promoting compounds in fruits, we studied whether the application of moderate UV-B radiation has an elicitor effect on secondary plant metabolism, and thus, subsequently change bioactive compound concentrations and composition in tomato fruits w...
Article
In the nearly airtight energy-saving greenhouses of the Northern countries, CO2 concentrations may drop to very low levels in autumn, winter and spring due to CO2 uptake by the plants, resulting in considerable yield decreases. Exhaust gas from the heating system is therefore added to the greenhouse air when natural gas is burned. In other cases, h...
Article
Total and individual glucosinolate contents of broccoli cv Marathon were assessed at ambient CO2 (430-480 ppm) and elevated atmospheric CO2 (685-820 ppm) to determine the ecological relationship between changing atmospheric CO2 concentrations and phytochemicals. Elevated atmospheric CO2 concentration had a differing effect on individual glucosinola...
Article
Due to the prognosticated warming in late autumn in northern and central Europe, the objective of this investigation was to establish whether temperature increase under low radiation conditions affect the content of phytochemicals such as carotenoids, chlorophylls and glucosinolates, and the also antioxidative effective ascorbic acid in broccoli. G...
Article
Root growth of cucumber is often believed to limit shoot growth and yield. It is generally accepted that the dry matter distribution between shoots and roots follows the principle of functional equilibrium, although the underlying mechanism of this is still not understood. This study aimed to investigate the effects of various environmental conditi...
Article
Tomatoes are an important source of lycopene in the human diet. The effect of temperature (15°C - 24°C), CO2 supply (380-1000 ppm) and nutrient concentration measured as electrical conductivity of the nutrient solution (EC, 2 - 9 dS m-1) on the content of carotenoids (lycopene, β-carotene) were investigated in two tomato cultivars grown in a greenh...
Article
Root systems might restrict plant growth, particularly under conditions of limited substrate volume and salinity buildup. The objective of this work was to develop a root growth-uptake model designed to evaluate the role of individual rhizospheric processes in plant development, particularly in closed loop irrigation systems. The model accounts for...
Article
Possibilities and limits of leaf area determination without destruction of leaves were examined. Length and width of tomato leaves (Lycopersicon spp.) were measured in different experiments. Allometry was examined, and its robustness was analyzed against treatment factors including genotype, salinity of the nutrient solution, growing system, and da...
Article
A method for the quantification of Pythium aphanidermatum density in cucumber roots based on an indirect enzyme-linked immunosorbent assay (ELISA) was established and tested. This approach was applied in three experiments under various environmental conditions. In addition, different inoculum densities were applied to vary the disease severity but...
Article
Tomato plants were grown in containers with aerated nutrient solution in a climate chamber at daily photosynthetic active radiation of 8 or 16 mol m -2, and inoculated with 0, 103 or 106 oospores of Pythium aphanidermatum per 1 of nutrient solution. Inoculum density affected propagule numbers of P. aphanidermatum both in the roots as well as in the...
Article
A decision support system (DSS) for managing greenhouse climate and crop fertigation was developed. It entails three modules: (i) a generic, modular substrate-plant-climate model designed to predict crop response to varying climate conditions, fertigation management, water quality and substrate characteristics, (ii) a management module that stores...
Article
Tomato plants were cultivated in a climate chamber in 12-L-containers with aerated nutrient solution at root-zone temperatures of 20, 25 and 30°C. Half of the containers were inoculated with oospores of Pythium aphanidermatum. During cultivation, the density of oospores in a sample of the nutrient solution was estimated one, three and five weeks af...
Article
A model was developed to predict the effects of environmental conditions on growth, yield and quality characteristics of broccoli. As an example of a quality characteristic, the content of the glucosinolate glucoraphanin - an important health affecting compound in broccoli - was estimated. Carbohydrates produced by photosynthesis are transformed in...
Article
Full-text available
Diurnal changes in microclimate in a greenhouse are often greater than changes in daily averages over weeks or months. Thus, one may hypothesize that changing the nutrient solution concentration supplied to plants at intervals less than one day would improve tomato yield and quality. To test this hypothesis research was conducted to compare four nu...
Conference Paper
An approach is introduced to describe the effect of root pathogens on plant growth and yield. As a part of this approach, a simplified submodel is presented of tomato root growth as affected by Pythium aphanidermatum infection and root zone temperature. Simulation studies using the model showed that root zone temperature has a great influence on ro...
Conference Paper
An increase in nutrient solution concentration to produce high-quality fruit vegetables, such as tomatoes, may reduce growth and yield. One reason might be inhibition of photosynthesis, but results of photosynthesis measurements in the literature are inconsistent. Therefore, growth and photosynthesis of whole tomato plants (Lycopersicon esculentum...
Conference Paper
A strategy to control the concentration of the nutrient solution, derived from models of photosynthesis and transpiration, was tested in a greenhouse experiment with tomato grown in rockwool in a closed growing system. The set point for the concentration of the nutrient solution (electrical conductivity) was calculated and adjusted once a day, as a...
Article
In 4 field experiments with broccoli (Brassica oleracea var. italica cv. Emperor) irradiance was varied by shading. Irradiance affected growth and yield all over the growing time. Reducing irradiance by 1 % resulted in a 0.9 % decrease of dry matter of plants at harvest and in a 1 % decrease of yield. Leaf area decreased by 0.5 % per 1 % reduction...
Conference Paper
For optimum nutrient use efficiency, nutrient demand and supply should be synchronized. A procedure is proposed describing the ratio of nutrient uptake to water uptake as a function of environmental conditions using models for photosynthesis and transpiration. Models were proved to be valid over a wide range of conditions. In a simulation study the...

Citations

... Tomato seeds ("Pannovy") were sown on 2 January 2018; 9 days after sowing, 48 seedlings were transplanted to stone-wool cubes and placed in a greenhouse controlled at 18 • C at the Leibniz Institute of Vegetable and Ornamental Crops (IGZ), Großbeeren, Germany (52.35 N 13.31 E). On 22 February 2018, 48 tomato plants were selected by uniformity and placed on inert fleece mats with drip irrigation in four rows of each 12 plants in one central compartment (28.8 m 2 ) of the gas-exchange greenhouse (GEGH) at the IGZ (Kläring and Körner, 2020). The remaining seven compartments were equipped in the same way, i.e., border effects were minimized. ...
... In contrast, daily N 2 O fluxes for NPK, CRO, and AUR ranged between 0.14 and 0.25 g N 2 O-N and were barely detectable with the used methodology. Only the total cumulative emissions of S+V (1335 ± 697 g N 2 O-N ha −1 ) were close to published findings for N 2 O emissions in greenhouse hydroponic cultivation (Daum 1996;Daum and Schenk 1996;Nett et al. 2019). Despite the higher N 2 O emissions associated with the S+V treatment, daily emissions appear to be, on average, below values found in the literature. ...
... The need D AGRICULTURAL IRRIGATION AND DRAINAGE ENGINEERING of large amounts and high quality vegetable products to meet the growing demand of world population justifies the development of technologies which synchronize the nutrient solution demand and supply to greenhouse plants in order to achieve crop yield optimization. The knowledge about water and nutrient uptake by plants is crucial for developing control strategies which make possible to supply the required amounts of water and nutrients for maximum crop growth and development (Kläring, 2001). Being a scarce resource, unevenly distributed and often in low quality, water is the key element of agriculture in arid and semiarid regions of the Mediterranean. ...
... Based on our results, the effects of DIF regulation on growth were predictable (Figure 7). This prediction method in conjunction with specific growing conditions and/or crop species might be important for practical application in horticulture (Kläring and Schmidt, 2017;Liu et al., 2019). However, as a limitation of this, other situations such as the 12/12 h temperature cycles were not addressed in this study, and further studies are required to determine the growth regulation of DIF. ...
... Furthermore, in the growing process occurs the compressibility of the substrate due to the action of mechanical forces during handling, compaction during transport or contraction of the substrate when there is variation in moisture content (wetting and drying), and segregation of fine particles at the bottom of the container during irrigation, causing the loss of the original form and place of the substrate and generating an alteration in the water/air substrate ratio (Lemaire, 1995; Abad et al., 2004). Improving the management of agricultural production systems using substrates, requires a greater knowledge base on the variation in physical properties during the crop cycle to manage the distribution of water and nutrients (Medrano et al., 2001; Suay et al., 2003) and improve commercial production systems (Kläring et al., 1999; Roca et al., 2003). Suay et al., 2003) y me�orar los sistemas de producción comercial (Kläring et al., 1999; Roca et al., 2003). ...
... Studies on CO2 enrichment in greenhouse settings show that yield of fruits and vegetables such as lettuce increased up to 30%, with accompanying significant increase in chemical composition. A higher yield and content of flavonoids and caffeic acid was realized in two red lettuce cultivars when CO2 enrichment was applied up to 1000 μmol mol −1 , and this could be attributed to the increase in sugars which serve as precursor for flavonoids biosynthesis [135]. Red lettuce cultivars seem more responsive to high CO2 than green lettuce, which was indicative of higher content of secondary metabolites and antioxidant activity [136]. ...
... Models improvements by implementation of dynamic LUE and SLA parameters depending on the radiation levels were carried out (Kage et al., 2001a ,b). In broccoli, reduced radiation levels also cause reduced dry matter production and an increase in SLA (Kläring, 1998; Mourão and Hadley, 1998; Francescangeli et al., 2007). Prediction models which include dry matter production with dynamic changes in SLA and LUE as functions of environmental conditions or models which consider plant to plant variation has been presented in literature. ...
... Several prediction models for production scheduling of broccoli and calculating mean time to harvest have been developed (Marshall and Thompson, 1987a,b;Scaife et al., 1987;Pearson and Hadley, 1988;Wurr et al., 1991Wurr et al., , 1992Grevsen, 1998Grevsen, , 2000Grevsen and Olesen, 1999;Tan et al., 2000a,b;Kläring et al., 2001). The model of Marshall and Thompson (1987a,b) calculates the time from sowing to harvest depending on solar radiation and temperature. ...
... ex Hornem) (Gosselin and Trudel, 1985;Diáz-Pérez et al., 2005). Root zone temperature also affects crop tolerance to pathogens, for example the fungi-like root pathogen Pythium aphanidermatum is tolerated by tomato plants at 20°C, but not at higher temperatures (Panova et al., 2004), while disease development increases in pepper at temperatures >23°C (Sopher, 2012). Fungal root pathogens also respond to elevated temperatures (O'Brien and van Bruggen, 1993). ...