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Growing season

About: Growing season is a research topic. Over the lifetime, 11214 publications have been published within this topic receiving 331886 citations.


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DissertationDOI
01 Jan 2010
TL;DR: In this article, the effects of CO enrichment and soil warming on the early growing season freezing resistance of 10 plant species were investigated in treeline treeline in the Swiss Alps, and the results suggest that leaf tissue damage caused by episodic early season freezing events will increase in frequency for some species in the coming decades.
Abstract: In situ studies lasting several years are essential for predicting how plant growth and ecosystem function will change under rising levels of atmospheric CO₂ and the associated changes in climate. High-latitude and high-elevation ecosystems are predicted to be particularly sensitive to environmental change, but relatively few manipulation experiments have been conducted in these regions. This doctoral thesis describes responses of two co-occurring tree species, Larix decidua and Pinus uncinata, and understorey dwarf shrub heath vegetation to 9 years of CO₂ enrichment (+200 ppm; 2001-2009) and 3 years of soil warming (+4 K; 2007-ongoing) at treeline in the Swiss Alps (Stillberg, Davos). We tested if elevated CO₂ stimulates tree growth in an environment where there is strong evidence that low temperature limits growth despite an adequate carbon supply. For this investigation, we pooled across soil warming treatments in order to focus on long-term responses to elevated CO₂. Larix ring width was stimulated by CO₂ enrichment throughout the treatment period, with a significant stimulation in years 3-7, while Pinus ring width showed no CO₂ effect. After 9 years of treatment, leaf canopy cover, stem basal area, and total new shoot production were greater in Larix trees growing under elevated CO₂, whereas Pinus showed no cumulative growth response. Larix ring width was stimulated more by elevated CO₂ in years with relatively high spring temperatures and an early snowmelt date, suggesting that temperatures were less limiting in these years and greater benefit was gained from extra carbon assimilated under elevated CO₂. The CO₂ effect size was also larger after relatively high temperatures and high solar radiation in the preceding growing season, perhaps reflecting gains due to larger carbon reserves. Contrasting responsiveness of these two species suggests that under future CO₂ concentrations, especially in combination with warmer and sunnier conditions, Larix will have a competitive advantage over less responsive species such as Pinus. Dwarf shrubs are a major component of alpine plant communities, and changes in the growth, abundance and distribution of these species are likely to have important ecological consequences. We studied growth responses of three dominant dwarf shrub species, Vaccinium myrtillus, Vaccinium gaultherioides and Empetrum hermaphroditum, to CO₂ enrichment and soil warming and how the treatments influenced understorey community composition. V. myrtillus growth was stimulated by elevated CO₂, with no decline over time in the annual shoot growth response, and to an even greater extent by soil warming. V. gaultherioides growth showed a slight positive effect of elevated CO₂, though only in experimental plots with Pinus, and no response to warming. E. hermaphroditum growth was not influenced by either treatment. Vascular plant species richness decreased in elevated CO₂ plots with Larix but not with Pinus, while the number of moss and lichen species decreased under soil warming. Overall, species-specific dwarf shrub growth responses indicate potential shifts in plant community composition at the alpine treeline. The frequency of freezing events during the growing season and the vulnerability to freezing of plants in temperate high-elevation environments could increase in the future. We conducted an experimental freezing study to determine effects of CO₂ enrichment and soil warming on the early growing season freezing resistance of 10 plant species. Long-term exposure to elevated CO₂ led to reduced freezing resistance in 5 species but did not influence phenology, implying that physiological changes caused by CO₂ enrichment were responsible for the effect. Soil warming showed little to no influence on the freezing resistance or phenology of the sampled species. Our results suggest that leaf tissue damage caused by episodic early season freezing events will increase in frequency for some species in the coming decades. The resulting shifts in relative freezing resistance among co-occurring species could alter competitive interactions. In an investigation of how the first season of soil warming influenced soil processes and ecosystem carbon balance, we found that soil respiration rates increased immediately with increased temperature while DOC leaching showed a delayed and much smaller response. Tracing of 13C-depleted CO₂ added for 7 years showed that the accelerated CO₂ effluxes from warmed soils were not driven by increased mineralization of recent plant litter and root respiration but by mineralization from older soil organic matter. Soil carbon losses clearly exceeded the estimated carbon accumulation by plants, which showed little response to one growing season of soil warming. These findings suggest that soil warming, representative of warmer and drier years, can lead to short-term carbon losses from alpine treeline ecosystems.

2 citations

Journal ArticleDOI
TL;DR: Water culture and sand culture seedlings of Scots pine were investigated in this article in respect to their reaction to ammonium or nitrate source of nitrogen nutrition, and the results indicated that the effect of various form of nitrogen Nutrition on gas exchange and growth rates could change during the growing season.
Abstract: Water culture and sand culture seedlings of Scots pine were investigated in respect to their reaction to ammonium or nitrate source of nitrogen nutrition. Photosynthesis, respiration, and dry matter production were studied in three and four months old plants. The results are preliminary but they have indicated that the effect of various form of nitrogen nutrition on gas exchange and growth rates could change during the growing season.

2 citations

Journal ArticleDOI
TL;DR: In this paper, the authors presented crop coefficient (Kc) values of TMV1-ST maize variety cultivated under deficit irrigation scheduling in Mkoji sub-catchment, Tanzania.
Abstract: This study presents crop coefficient (Kc) values of TMV1-ST maize variety cultivated under deficit irrigation scheduling in Mkoji sub-catchment, Tanzania. Field experiments consisting of eight (8) treatments were conducted in 2004 and 2005 irrigation seasons. The treatments variation was irrigation intervals. The control treatment was irrigated on weekly basis while the other treatments were irrigated every other week at one or more growth stages of the maize crop. Surface irrigation method was used and soil moisture contents were monitored weekly throughout the crop growing season from which weekly crop actual evapotranspiration was computed. Weather data of the study location were used to compute weekly reference evapotranspiration based on the FAO-Penman- Monetieth model. Crop coefficients were computed as the ratio of crop actual evapotranspiration of the different treatments to reference evapotranspiration on weekly basis. Water stress coefficients were also computed. The crop coefficients had similar trend in the two seasons which make them reliable. The average crop coefficient (Kc) of the fully irrigated treatment for the two seasons for the establishment, vegetative, flowering and grain filling stages were 0.53,0.82,1.10, and 1.06, respectively, while the average crop coefficients of the deficit irrigated treatments (Kc') for the two seasons for the establishment, vegetative, flowering and grain filling stages were 0.53, 0.75, 0.94, and 0.78, respectively. Withholding regular irrigation at any crop growth stage reduced crop coefficient by between 17 to 30 %, while withholding regular irrigation at two or more successive growth stages of the maize crop reduced crop coefficient by about 40 %. The water stress coefficient (Ks) resulting from deficit irrigation at any one growth stage only of the maize crop were found to range from 0.74 to 0.83, while deficit irrigation at two or more successive growth stages ranged from 0.68 to 0.77. The crop and water stress coefficients developed from this study could be used in irrigation systems planning and design for the study area in Tanzania.

2 citations

Journal ArticleDOI
28 Dec 2019
TL;DR: In this paper, the authors evaluated the effect of integration of chemical fertilizer (triple superphosphate) with manure (cattle residue) and/or biofertilizer (Aspergillus niger) on some soil properties and phosphorus availability to sunflower during growing season.
Abstract: Field experiment was conducted in Mohajaran region, Abu-Al-Khaseeb district, Basrah province during the growing season 2018. The study was aimed to evaluate the effect of integration of chemical fertilizer (triple superphosphate) with manure (cattle residue) and/ or biofertilizer (Aspergillus niger) on some soil properties and phosphorus availability to sunflower during growing season. Samples were collected at seedling, vegetative growth, flowering and post-harvest stage. pH, EC, moisture content and available P were determined. Results showed that application of chemical fertilizer significantly affected soil pH, EC, and available P, but showed no effect on soil moisture content. Soil pH decreased and EC increased at seedling stage, while EC was decreased at harvest. Available P values were increased at all growing stages. Incorporation of manure at rate of 30 Mg ha-1 considerably decreased the soil pH and increased EC at seedling stage, soil moisture, and available P at all growing stages.. Inoculation the seeds with A. niger showed no significant effect on soil pH, EC, and soil moisture but significantly increased available P, at vegetative growth and flowing stages . Results showed that the effect of biofertilizer on available P was in bar with the application of manure at rate of 15 Mg ha-1 .Highest value of available P was associated with combination of 120 Kg P ha-1 + 30 Mg ha-1 + inoculation with fungus.

2 citations

Journal ArticleDOI
TL;DR: The comparison of SMA-C simulations with the observed data showed inaccuracies in estimation of soil water storage due to model underestimation for ETc, and estimates were improved by adjusting the model to consider Kc measured in the field.
Abstract: Many simulation models found in the literature integrates data on climate and crop characteristics to provide great information on the season for different crops. The objectives of this study were: a) to measure soil water balance components of a wheat crop to determine its evapotranspiration (ETc) and crop coefficients (Kc) during the growing season; b) to use experimental data to evaluate the performance of SMA-C in estimating evapotranspiration for a wheat in Parana State, Brazil; and c) to make adjustments to improve mod`el estimates. Two weighing lysimeters cultivated with a wheat crop were used to measure soil water storage and ETc during the growing season of a wheat crop. Reference evapotranspiration (ETo) was determined by FAO 56 method using data from a local weather station. Wheat crop coefficients were calculated by the ratio ETc/ETo, were 0.7, 1.5 and 0.6, for initial, mid and late season, respectively. The comparison of SMA-C simulations with the observed data showed inaccuracies in estimation of soil water storage due to model underestimation for ETc. Estimates were improved by adjusting the model to consider Kc measured in the field. Key words: Models, lysimeters, decision-making support.

2 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023653
20221,340
2021598
2020547
2019503
2018470