Adverse Temperature Conditions Research Articles

Summer overheating of a passive sports hall building

Reported measurements were intended as a preliminary check of a free run of a sports hall passive building in summer conditions. Indoor microclimate measurements lasted for three hot summer days and were carried out at the time when there was no building occupancy. In adverse conditions of high ambient air temperature and switched off ventilation acute overheating was observed. Night cooling, easily available measure of overheating protection was not applied, so there was no chance for discharge of high internal capacity of this building. A specific mode of building management had a critical impact on its internal microclimate and would raise user dissatisfaction. In close perspective of widespread implementation of near zero energy building standard, often reported overheating problem becomes an important issue. It was also shown that thermal comfort measurements may be unexpectedly and substantially affected by window location and solar radiation geometry.

Efficiency of weather derivatives for Chinese agriculture industry

Purpose – The purpose of this paper is to analyze the efficiency of temperature-based weather derivatives (WD) in reducing risk exposure for Chinese agriculture industry. Therefore, a put option with cumulated growing degree days as its underlying index is assumed to be bought by farmers as a risk management instrument to prevent income fluctuations from adverse temperature conditions. Design/methodology/approach – The objective of this paper is to analyze the efficiency of temperature-based WD in reducing risk exposure for Chinese agriculture industry. Therefore, a put option with cumulated growing degree days as its underlying index is assumed to be bought by farmers as a risk management instrument to prevent income fluctuations from adverse temperature conditions. Findings – The results of the efficiency tests show that temperature-based put options are efficient in offsetting yield shortfalls for rice and wheat in China. The weather-yield models have a high prediction power in explaining yield variation by temperature. Research limitations/implications – The de-trending procedure for the weather-yield model should be improved to distinguish better between technology progress, human activities and influence of weather. Further, more advanced models could be used for the pricing. Practical implications – The findings of the paper support the launch of WD as an efficient risk management tool for agriculture in China. Compared with traditional damage-based insurance, WD are more flexible, have lower transactions costs and avoid moral hazard or adverse selection. Originality/value – The efficiency problem of WD has not been analyzed sufficiently worldwide and especially not for developing countries like China where a large proportion of the population works as farmers. This paper supports to fill this gap.

저온에 대한 식물의 양분흡수, 탄수화물 및 항산화 반응 특성

Recently, a quick drop of air temperature in plastic film houses by adverse weather conditions leads to the occurrence of low temperature damages to growing crops. Chilling injury, defined as a variety of growth restriction occurring below the optimal temperature, is one of environmental factors strongly affecting crop growth and yield. Low temperature causes the restricted evapotranspiration, reduced mineral uptake (P > K > <TEX>$NO_3{^-}$</TEX>), and an increase in electrolyte leakage such as K. Despite being different with plant species, an accumulation of soluble carbohydrates such as glucose, fructose, sucrose and starch under chilling condition is well known. A variety of environmental stresses are known to cause oxidative damage to plants either directly or indirectly by triggering an increased level of production of reactive oxygen species (ROS), and, to combat the oxidative damage, plants have the antioxidant defense systems comprising of enzymes, SOD, POD, CAT, GPX and APX, and non-enzymes, ascorbate, gluthathione, <TEX>${\alpha}$</TEX>-tocopherol, phenolic compounds, carotenoid and flavonoids. The aim of this review is to provide basic information to build chilling-indicators and optimal nutrition management under adverse temperature conditions as broadly considering mineral uptake, carbohydrate metabolism and antioxidative defense system.

Nondestructive Determination Of Beans Water Absorption Capacity Using CFA Images Analysis For Hard-To-Cook Evaluation

Hard to cook (HTC) phenomenon is developed by storing bean grains under the adverse conditions of high temperature (≥ 25 °C ) and high humidity (≥ 65 %). Bean grains that have undergone this HTC phenomenon are characterized by loss of color lightness, development of browning and darkening, and decrease of Water Absorption Capacity (WAC). The objective of this study was to develop a CFA (Color Filter Array) image processing system to measure Water Absorption Capacity (WAC) of bean grains with high precision in short time intervals (10 min). The relationships between the CFA image features, extracted from raw images captured by CCD (charge coupled device) camera, and the measured WAC were established. The calibration models using multiple linear regression (MLR) were developed to predict WAC. The MLR models for prediction samples resulted in correlation coefficient (R2) in the range of 0.811 to 0.947, standard error of prediction (SEP) in the range of 7.587 to 11.669, and Fisher variable value (F) in the range of 52.300 to 221.690. Results indicate that computer vision system (CVS) based on CFA image analysis technique can provide an accurate, reliable and nondestructive measurement method of WAC to evaluate the hard to cook defect in bean grains. DOI: http://dx.doi.org/10.11591/ijece.v3i2.2149

Nondestructive Determination Of Beans Water Absorption Capacity Using CFA Images Analysis For Hard-To-Cook Evaluation

Hard to cook (HTC) phenomenon is developed by storing bean grains under the adverse conditions of high temperature (≥ 25 °C ) and high humidity (≥ 65 %). Bean grains that have undergone this HTC phenomenon are characterized by loss of color lightness, development of browning and darkening, and decrease of Water Absorption Capacity (WAC). The objective of this study was to develop a CFA (Color Filter Array) image processing system to measure Water Absorption Capacity (WAC) of bean grains with high precision in short time intervals (10 min). The relationships between the CFA image features, extracted from raw images captured by CCD (charge coupled device) camera, and the measured WAC were established. The calibration models using multiple linear regression (MLR) were developed to predict WAC. The MLR models for prediction samples resulted in correlation coefficient (R2) in the range of 0.811 to 0.947, standard error of prediction (SEP) in the range of 7.587 to 11.669, and Fisher variable value (F) in the range of 52.300 to 221.690. Results indicate that computer vision system (CVS) based on CFA image analysis technique can provide an accurate, reliable and nondestructive measurement method of WAC to evaluate the hard to cook defect in bean grains. DOI: http://dx.doi.org/10.11591/ijece.v3i2.2149

Invasion and adaptation of a warm adapted species to montane localities: effect of acclimation potential

Drosophila ananassae has successfully invaded the cold and dry montane localities of the Western Himalayas in recent years. The ability of this desiccation- and cold-sensitive tropical species to evolve in response to seasonal changes in montane localities is largely unknown. Here, we investigated how this sensitive species adapt to seasonally varying environmental conditions that are lethal to its survival. We observed change in the frequency of dark and light morphs of D. ananassae in five mid-altitude localities during the last decade (2000-2010). We document invasion of D. ananassae to montane localities and increase in frequency of the dark morph. The stress tolerance of morphs (dark and light) remained unaffected of developmental acclimation. However, adult acclimation has shown significant effects on tolerance to various environmental stresses in morphs and effect of this acclimation persist for long durations. Desiccation and cold stress tolerance was increased after adult acclimation for respective stress in the dark morph; while tolerance of the light morph was not affected. Further, heat tolerance of the light morph was increased after adult heat acclimation with no influence on heat tolerance of the dark morph. Our results suggest a possible role of adult acclimation in successful invasion and adaptation of D. ananassae to montane localities. Future experiments should be carried out to determine whether the survival in adverse conditions of low versus high temperature and humidity during seasonal changes is assisted by different acclimation abilities of the two morphs of D. ananassae.

Seasonal Patterns in White Crappies' Consumption and Growth: Influences of Varying Water Temperatures and Prey Availability

AbstractCrappies Pomoxis spp. are popular sport fishes but often fail to achieve sizes that are acceptable to anglers. While many factors may contribute to episodes of suboptimal growth in crappies, insufficient densities of prey fish and high summer water temperatures (&gt;27°C) have been considered to be key underlying causes. We examined the influences of prey fish size, prey availability, and water temperature on the consumption and growth of white crappies P. annularis (ages 1–3) in three Missouri reservoirs over five successive years. Monthly growth rates were estimated using aging analyses, while consumption was estimated using a bioenergetics model. All age‐groups grew fastest in the reservoir that was warmest but in which prey fish availability was the highest. Diet analyses coupled with bioenergetics modeling suggested that white crappies were able to maintain positive growth rates at temperatures exceeding 27°C by maximizing consumption rates when adequate prey fish resources were available. When sufficient prey fish resources were unavailable, white crappies fed on invertebrates and often ceased growing or lost weight, even during periods with suitable water temperatures. Our study documents the importance of adequate prey fish resources for maintaining positive growth rates of white crappies, especially during periods of adverse temperature conditions.

Specifications for temperature and humidity in sterile storage environments – Where's the evidence?

The concept of event-related sterility for storage of medical devices is widely applied in Australian healthcare facilities. This paper reviews available literature, international standards and guidance documents with respect to the concept of event-related sterility in order to determine: (i) why commercially produced sterile medical devices may withstand adverse temperature and humidity conditions better than items produced in a Sterile Services Department; (ii) what effects temperature and humidity have on maintenance of sterility; and (iii) whether temperature and humidity conditions specified in AS/NZS4187:2003 are evidence-based and whether changes to these could be made in any future revisions. The literature review revealed that manufacturers of commercially available sterile medical devices are subject to stringent medical device regulations that require them to ensure that the devices remain both fit for purpose and sterile until use. This necessitates that manufacturers conduct accelerated ageing and environmental challenge tests to establish and justify the expiry dates given on the package label. The review also found a variety of specifications for temperature and humidity and the guidance documents gave no indication of evidence used as a basis for these requirements. In addition, it was apparent that many published studies on event-related sterility did not include consideration of the effect of temperature and humidity on the duration of sterility. After examination of a range of published material, it was concluded that the specifications in any future edition of AS/NZS4187 could be expanded to a temperature range of 16–25°C and a relative humidity range of 30–75%.

Solar Pond devices: free energy or bioreactors for Artemia biomass production?

The recent exponential growth in industrial aquaculture has led to a huge increase in Artemia biomass production in order to meet increased fish production needs. The present study explores the potential use of salt gradient solar ponds (SGSPs) for production of Artemia nauplii. An SGSP is a basin of water where solar energy is trapped and collected via an artificially imposed gradient. Three zones can be identified in an SGSP: upper and lower zones, which are both convective, and a middle zone, which is intended to be non-convective. The latter acts as a transparent insulation layer and allows for storage of solar energy at the bottom, where it is available for use. The combination of salt, temperature and high transparency could make SGSPs promising bioreactors for the production of Artemia nauplii. Using particle image velocymetry (PIV) and Shadowgraph visualisation techniques, the behaviour of Artemia nauplii under critical cultivation parameters (namely, salinity, temperature and light) was monitored to determine movement velocity, and how movement of Artemia affects the salt gradient. It was observed that Artemia nauplii constantly follow light, irrespective of adverse salinity and/or temperature conditions. However, despite the substantial displacement of Artemia following the light source, the salt gradient is not disrupted. The suitability of SGSPs as bioreactors for Artemia biomass production was then tested. The results were disappointing, probably due to the lack of sufficient O(2) for Artemia survival and growth. Follow-up trials were conducted aimed at using the SGSP as a green and economically attractive energy source to induce faster hatching of cysts and improved Artemia nauplii growth. The results of these trials, and a case study of Artemia nauplii production using an SGSP, are presented. The authors constructed a Solar Pond device, which they suggest as a novel way of supplying thermal energy for Artemia biomass production in an aquaculture enterprise. Finally, the authors suggest a method of producing and collecting Artemia biomass, and of heating a fish larval tank, in an 'ideal' Solar Pond device, profiting from the low investment costs of using a decommissioned salt works.

Production of reactive species and modulation of antioxidant network in response to heat shock: a critical balance for cell fate

Exposure to adverse temperature conditions is a common stress factor for plants. In order to cope with heat stress, plants activate several defence mechanisms responsible for the control of reactive oxygen species (ROS) and redox homeostasis. Specific heat shocks (HSs) are also able to activate programmed cell death (PCD). In this paper, the alteration of several oxidative markers and ROS scavenging enzymes were studied after subjecting cells to two different HSs. Our results suggest that, under moderate HS, the redox homeostasis is mainly guaranteed by an increase in glutathione (GSH) content and in the ascorbate peroxidase (APX) and catalase (CAT) activities. These two enzymes undergo different regulatory mechanisms. On the other hand, the HS-induced PCD determines an increase in the activity of the enzymes recycling the ascorbate- and GSH-oxidized forms and a reduction of APX; whereas, CAT decreases only after a transient rise of its activity, which occurs in spite of the decrease of its gene expression. These results suggest that the enzyme-dependent ROS scavenging is enhanced under moderate HS and suppressed under HS-induced PCD. Moreover, the APX suppression occurring very early during PCD, could represent a hallmark of cells that have activated a suicide programme.

Intracellular glasses and seed survival in the dry state

So-called orthodox seeds can resist complete desiccation and survive the dry state for extended periods of time. During drying, the cellular viscosity increases dramatically and in the dry state, the cytoplasm transforms into a glassy state. The formation of intracellular glasses is indispensable to survive the dry state. Indeed, the storage stability of seeds is related to the packing density and molecular mobility of the intracellular glass, suggesting that the physico-chemical properties of intracellular glasses provide stability for long-term survival. Whereas seeds contain large amounts of soluble non-reducing sugars, which are known to be good glass formers, detailed in vivo measurements using techniques such as FTIR and EPR spectroscopy reveal that these intracellular glasses have properties that are quite different from those of simple sugar glasses. Intracellular glasses exhibit slow molecular mobility and a high molecular packing, resembling glasses made of mixtures of sugars with proteins, which potentially interact with additional cytoplasmic components such as salts, organic acids and amino acids. Above the glass transition temperature, the cytoplasm of biological systems still exhibits a low molecular mobility and a high stability, which serves as an ecological advantage, keeping the seeds stable under adverse conditions of temperature or water content that bring the tissues out of the glassy state. To cite this article: J. Buitink, O. Leprince, C. R. Biologies 331 (2008).

Validation of the UN criteria for the uncooled sea transport of liquid organic peroxides: Full-scale test and modeling

In the years 1987 and 1988 TNO and Akzo Nobel investigated the thermal safety of non-temperature-controlled sea transport of organic peroxides, by modeling and experimenting on several scales. A full-scale test was organised in the summer of 1989, in co-operation with the former Nedlloyd company, in which a sea container with palletised packages, filled with soybean oil as inert liquid and fully equipped with temperature measuring equipment, was transported from Rotterdam, The Netherlands, to Beira, Mozambique, and back. The trip took 2 months. To answer questions stated by the workgroup International Group of Experts on the Explosion Risk of Unstable Substances—subgroup on Energetic and Oxidising Substance (IGUS-EOS) during its meeting in Washington, DC, USA, April 2006, the original data of the sea-container trip were reviewed and applied in a new mathematical model of the sea-container filled with packages, and traveling through tropical sea areas. Analysis of the data from the full-scale test led to defining a worst combination of adverse temperature conditions: constant dead sailing of the wind (wind direction and speed equal to that of the ship), and sunny weather 12 h/day and a mean ambient temperature of 30 °C during 28 days. The effect of sunny weather was put into the model by assigning 24 h averaged excess temperatures to the sun-exposed surfaces. New simulations showed no runaway for the sea container, if filled with an organic peroxide having an self-accelerating decomposition temperature (SADT) of exactly 55 °C. The exaggerated worst case with an improbable mean ambient temperature of 33 °C also does not lead to a runaway. Therefore, the UN criteria for temperature control for organic peroxides are appropriate.

Recovery of Phytophthora ramorum Following Exposure to Temperature Extremes

We examined the impact of exposure to high and low temperature extremes on recovery of Phytophthora ramorum both as free chlamydospores and within infected rhododendron tissue over a 7-day period. Chlamydospores held in moistened sand were incubated at 30, 35, 40, 0, -10, and -20°C for up to 7 days. Infected Rhododendron 'Cunningham's White' leaf disks held in sandy loam, loam, or sand at two different soil moisture levels also were subjected to these temperatures for up to 7 days, and to a variable temperature regimen for 12 weeks. Recovery was characterized by growth of P. ramorum on selective agar medium following exposures to temperature treatments. Chlamydospores held in moistened sand showed a high rate of recovery at 30°C, steadily declining recovery at 35°C, and no recovery at 40°C over the 7-day period. Chlamydospores were recovered from 0°C after 7 days, with little or no recovery observed at -10 or -20°C. In infected rhododendron tissue, P. ramorum was recovered at 20 and 30°C after 7 days but, at 35°C, the pathogen showed a decline within 2 days and no recovery by 4 days. A 40°C treatment allowed no recovery of P. ramorum from infected tissue after 2 days. For cold treatments, P. ramorum was recovered from infected leaf disks at 0 and -10°C after 7 days. At -20°C, recovery declined rapidly after 1 to 3 days and no recovery was obtained after 4 days. P. ramorum showed nearly 100% recovery from leaf disks subjected to a 12-week variable temperature treatment based on ambient summer temperatures in Lewisburg, TN. The results suggest that P. ramorum is capable of surviving some highly adverse temperature conditions for at least 7 days both as free chlamydospores in sand and within infected host tissue. Thus, P. ramorum present as free chlamydospores or within tissue of infected plants shipped to the eastern United States has the potential to survive some of the adverse conditions encountered in summer and winter in many eastern states.

Pharmacological strategies for the management of cancer pain in developing countries.

Pain associated with cancer is often under treated especially in the developing countries where there are problems of poor economy, poor purchasing power of the citizens, absence of effective national health insurance schemes, poor manpower, fake adulterated and expired drugs, poor drug storage conditions; adverse temperature conditions combined with poor power supply which may affect drug efficacy. There is also poor understanding of the physiopharmacology of cancer pain management by health care providers. Assessment of the severity of the pain by location, oncological type, as well as psychosocial, emotional and environmental factors are necessary. The pain often occurs from malignancy, from procedures done to diagnose, stage and treat the malignancy, and from the toxicities of therapy used in treating the cancer. The first priority of treatment is to control pain rapidly and completely, as judged by the patient. The second priority is to prevent recurrence of pain. Analgesic drugs are given 'by the ladder,' 'by the clock' and 'by the appropriate route' using the analgesic ladder guideline proposed by the World Health Organization (WHO). The pharmacological aspects of various drugs used in the management of cancer pain are discussed.

Depósito de pulverização com diferentes padrões de gotas em aplicações na cultura do algodoeiro

Com os objetivos de avaliar a deposição da calda de pulverização sobre plantas de algodão e a eficiência da pulverização com diferentes padrões de gotas sob condições adversas de temperatura e umidade, realizou-se um experimento para a determinação dos volumes de depósitos da pulverização no final de ciclo da cultura. O trabalho foi executado com pulverizador automotriz, equipado com pontas JA3 (jato cônico vazio) e jato plano com indução a ar AD-IA/D 11003 (duplo), AD-IA 11003 que, na pressão trabalhada, proporcionaram volume de aplicação de 150 L ha-1, e a ponta AD-IA 11004 que, na mesma pressão, proporcionou volume aplicado de 200 L ha-1. Para a determinação dos volumes depositados nas folhas do terço superior, médio e inferior das plantas de algodão, utilizou-se do corante alimentício azul brilhante adicionado à calda de pulverização, na concentração de 0,179%. Após a pulverização, as folhas foram lavadas, e o volume recuperado foi analisado por espectrofotometria. Os resultados obtidos foram submetidos à análise de regressão pelo modelo de Gompertz para a comparação entre os tratamentos. A ponta AD-IA 11003 proporcionou os maiores volumes de depósito nas diferentes posições da planta, e a eficiência da aplicação foi de 27,45; 35,08; 47,60 e 39,25% para as pontas JA3, AD-IA/D 11003, AD-IA 11003 e AD-IA 11004, respectivamente.

Fluidic Valves for Variable-Configuration Gas Treatment

The paper surveys recent development in the highly specialized field of chemical engineering: vehicle exhaust gas aftertreatment, where variable configuration systems are currently introduced or considered. These respond to varying operating conditions by inserting into the gas treatment flowpath different reactors. The main practical problem are the valves for gas flow switching. Usual mechanical valves are costly, failure prone, heavy (especially the solenoid variants), and not robust enough to withstand the adverse conditions of high temperature, vibration, shocks and dripping water and mud at the usual locations under vehicle body. Fluidic no-moving-part valves, inexpensive and robust, are proposed as an attractive alternative. Especially in their novel axisymmetric layout, they may be very compact, in fact integral with reactor body. The qualitative change brought by the new approaches may provide an inspiration to other areas of chemical engineering.

Effect of competition and adverse culture conditions on aflatoxin production by Aspergillus flavus through successive generations

Strains of Aspergillus flavus often degenerate with serial transfers on culture media, resulting in morphological changes and loss of aflatoxin production. However, degeneration does not readily occur in nature as indicated by the wild-type morphological characters of newly isolated strains and the high percentage of aflatoxigenic A. flavus from soil and crops in some geographic regions. In this study, three aflatoxin-producing strains of A. flavus were serially transferred using conidia for 20 generations (three independent generation lines per strain) on potato dextrose agar at 30 C. The rate of degeneration was compared to that of cultures grown in the presence of competing fungi (A. terreus, Penicillium funiculosum, and the yeast, Pichia guilliermondii) and under adverse conditions of elevated temperature, reduced water activity, low pH, and nutrient deprivation. Formation of morphological variants and the associated loss of aflatoxin production over generations varied considerably according to strain and the generation line within each strain. In the strain most sensitive to degeneration on potato dextrose agar, aflatoxin-producing ability was maintained to varying degrees under adverse culture conditions, but not when A. flavus was competing with other fungi.

Stability Study of Flutamide in Solid State and in Aqueous Solution

ABSTRACTA high-performance liquid chromatography (HPLC) assay has been developed for the determination of flutamide and its degradation products. Using this method, the influence of important formulation factors on the stability of flutamide has been estimated. The stability studies have been carried out in solid state as well as in aqueous solution. The results obtained have shown a good stability for flutamide in solid state. This drug remained practically unchanged after a four-month assay in adverse temperature and humidity conditions. On the other hand, the results obtained from the stability study in solution during 12 days have shown that flutamide in aqueous solution underwent a clear degradation at mean or high temperature (22°C, 37°C) and acidic pH conditions (1.1). With respect to the influence of ionic strength, it has been found that the presence of sodium chloride prevents the degradation of flutamide in aqueous solution. The second-order kinetics model provides the best fit for highly degraded solutions.

Composición química y calidad nutritiva de garbanzo (Cicer arietinum L.) fresco y endurecido después de la fermentación en estado sólido (FES)/Chemical composition and nutritional quality of fresh and hardened chickpea (Cicer arietinum L) after the solid state fermentation (SSF)

Solid state fermentation (SSF) represents a technological alternative for a great variety of legumes and cereals, or combinations of them, to improve their nutritional quality and to obtain edible products with palatable sensorial characteristics. Chickpeas (Cicer arietinum L.) are prone to develop the hardening phenomenon, also known as hard-to-cook (HTC) defect, when stored under adverse conditions of high temperature (≥ 25 °C) and high relative humidity (≥ 65%). This hard-to-cook phenomenon causes increases in cooking time, decreases in nutritional quality and deterioration of sensorial attributes of chickpea. The objective of this work was to study the effect of SSF on chemical composition and nutritional quality of fresh and hardened chickpeas. The hardening of chickpea ( Cicer arietinum L. Blanco Sinaloa 92 variety) for human consumption, was produced by accelerated storage (33-35 °C, RH = 75%, 180 days). A Rhizopus stolonifer spore suspension (1 x 106 spores/mL) was used as starter for the fermentation. The temperature and time of the SSF process were 35.8 °C and 42.7 h, respectively. The tempeh was obtained from fresh and hardened chickpea. The SSF process caused a significant increase ( p ≤ 0.05) in crude protein, true protein (19.6-19.9 to 23.2-23.4%), protein solubility, in vitro digestibility (68.6-73.1% to 79.9-80.5%), available lysine (2.19-3.04 to 3.19-4.07 g lysine/ 16 N), palmitic acid, and stearic acid, and a significant decrease ( p ≤ 0.05) in lipids, minerals, linoleic acid, phytic acid (8.82-10.73 to 2.11 g phytic acid/g dry matter), and tannins (16.1-22.4 to 3 mg catechin/g dry matter). The SSF process improved significantly the quality of fresh and hardened chickpea.

Application of computer captured knowledge in land evaluation, using ALES in central Ethiopia

Quickly obtained, simple and reproducible information about the potentials and constraints of land can be obtained through capturing expert knowledge in a computer system. In this paper, an approach to an expert system in land evaluation is described, involving local expertise in decision making. A simple decision procedure, referred to as Land EValuation system for Central EThiopia (LEV-CET), is developed using the facilities of ALES: Automated Land Evaluation System (Rossiter and Van Wambeke, 1989). The model is applied to evaluate land use potentials in a sample area in central Ethiopia for barley, maize and teff. Outputs from LEV-CET indicate that the high altitude areas have severe climatic limitations for all three crops. The central and southern parts are climatically highly suitable for teff and barley, and moderately suitable for maize. Major limitations to crop production are adverse conditions of temperature, wetness and rooting. Consistent yield improvements can be expected by a proper choice of crops or alternative land uses, and/or by concentrating on a better management ofvpoorly drained land.