Drought-induced decline in oak Mediterranean forests: insights from wood anatomical traits

2020 ◽  
Author(s):  
Michele Colangelo ◽  
Angelo Rita ◽  
Marco Borghetti ◽  
Jesus Julio Camarero ◽  
Tiziana Gentilesca ◽  
...  
Keyword(s):  
Drought Stress ◽  
Field Experiments ◽  
Mediterranean Forests ◽  
Quercus Pubescens ◽  
Forest Dieback ◽  
Stress Effects ◽  
Anatomical Plasticity ◽  
Growth Changes ◽  
Growth Divergence

<p>Increased forest vulnerability to drought and heat spells is being reflected as more widespread and severe dieback events. In this regard, the Mediterranean Basin is revealing a high susceptibility to these phenomena across several tree taxa with a high ecological and socio-economic importance, particularly pines and oaks. For instance, oaks are particularly vulnerable to spring-summer droughts with important losses in term of growth and productivity accompanied by rising mortality rates and declining growth rates, despite some of these species are theoretically considered well-adapted to tolerate drought stress. Dendroecological studies using retrospective analysis of wood anatomical traits and tree-rings have demonstrated their potential to supply useful information on the long-term patterns of forest dieback in several oak species.  </p><p>In this study, we explored the xylem anatomical plasticity through time by performing a long-term (1980-2017) reconstruction of wood anatomical traits, aiming at investigate the drought stress effects on dieback of oak species.To this aim, we carried out some field experiments in Italy on four oak species differing in drought tolerance, i.e. Quercus robur, Quercus cerris, Quercus frainetto and Quercus pubescens, considered to have low to high tolerance, respectively, but showing recent decline phenomena. We cored asymptomatic (ND) and symptomatic (D) coexisting trees showing low and high defoliation levels, respectively, and for all sampled species we measured the following anatomical traits in the xylem: vessel area, Dh, vessel density.</p><p>Climate-traits relationships over the last century explained the recent growth divergence observed between D and ND trees because D trees were more sensitive[U1]  to drought stress and summer warm temperatures leading to high evapotranspiration rates. Here, we discuss: i) the relationships between radial growth, changes in wood anatomy and hydraulic functioning of trees to highlight the triggers of oak dieback; ii) the associations between climate, growth and anatomy data to explain likely the differences in acclimation/plasticity to short/long-term changes in environmental conditions.</p>

scholarly journals Effects of disk tillage on soil condition, crop yield and weed infestation

2011 ◽  
Vol 48 (No. 1) ◽  
pp. 20-26
Author(s):  
M. Birkás ◽  
T. Szalai ◽  
C. Gyuricza ◽  
M. Gecse ◽  
K. Bordás
Keyword(s):  
Winter Wheat ◽  
Crop Yield ◽  
Field Experiments ◽  
Soil Layer ◽  
Soil Condition ◽  
Perennial Weeds ◽  
Weed Infestation ◽  
Set Up ◽  
Different Levels

This research was instigated by the fact that during the last decade annually repeated shallow disk tillage on the same field became frequent practice in Hungary. In order to study the changes of soil condition associated with disk tillage and to assess it is consequences, long-term tillage field experiments with different levels of nutrients were set up in 1991 (A) and in 1994 (B) on Chromic Luvisol at Gödöllö. The effects of disk tillage (D) and disk tillage combined with loosening (LD) on soil condition, on yield of maize and winter wheat, and on weed infestation were examined. The evaluation of soil condition measured by cone index and bulk density indicated that use of disking annually resulted in a dense soil layer below the disking depth (diskpan-compaction). It was found, that soil condition deteriorated by diskpan-compaction decreased the yield of maize significantly by 20 and 42% (w/w), and that of wheat by 13 and 15% (w/w) when compared to soils with no diskpan-compaction. Averaged over seven years, and three fertilizer levels, the cover % of the total, grass and perennial weeds on loosened soils were 73, 69 and 65% of soils contained diskpan-compaction.

Critical plant phosphorus for winter wheat assessed from long-term field experiments

2021 ◽  
Vol 126 ◽  
pp. 126263
Author(s):  
Mario Fontana ◽  
Gilles Bélanger ◽  
Juliane Hirte ◽  
Noura Ziadi ◽  
Saïd Elfouki ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Field Experiments ◽  
Term Field

Biochar Application and Drought Stress Effects on Physiological Characteristics ofSilybum marianum

2016 ◽  
Vol 47 (6) ◽  
pp. 743-752 ◽  
Author(s):  
R. Keshavarz Afshar ◽  
M. Hashemi ◽  
M. DaCosta ◽  
J. Spargo ◽  
A. Sadeghpour
Keyword(s):  
Drought Stress ◽  
Physiological Characteristics ◽  
Stress Effects

Long-term field experiments of the world

2003 ◽  
Vol 49 (5) ◽  
pp. 465-483 ◽  
Author(s):  
Katalin Debreczeni ◽  
Martin Körschens
Keyword(s):  
Field Experiments ◽  
The World ◽  
Term Field

The long-term persistence of seeds of oilseed rape (Brassica napus) in arable fields

2003 ◽  
Vol 141 (2) ◽  
pp. 231-240 ◽  
Author(s):  
P. J. W. LUTMAN ◽  
S. E. FREEMAN ◽  
C. PEKRUN
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Field Experiments ◽  
Petri Dish ◽  
Initial Field ◽  
Seed Loss ◽  
Exponential Decline ◽  
Arable Fields ◽  
Decline Curves

The present paper reports on three sets of experiments exploring the persistence of seeds of oilseed rape (Brassica napus). The first, where known numbers of seeds were buried in September 1991 in two field experiments, demonstrated substantial initial losses of seeds, such that only 0·2 and 3·8% of seeds were still present after 4 months. In these experiments, which were not disturbed by mechanical cultivation, there was little evidence of further decline over the following 13 months. In the second of the two experiments, seeds were then left undisturbed for a further 136 months. A mean of 1·8% of seeds were still present after this period, providing further confirmation of the lack of decline in seed numbers in these undisturbed conditions. In the second pair of experiments, known numbers of seeds of three rape cultivars were broadcast onto plots and then either ploughed into the soil immediately after the start of the experiments, or were exposed to weekly shallow tine cultivation followed by ploughing after 4 weeks. The former created a larger seedbank than the latter. The experiments were then ploughed, annually (Expt 1) or at less frequent intervals (Expt 2); appreciable numbers of seeds survived for 65 months in both. Calculations based on exponential decline curves indicated that 95% seed loss would take 15–39 months, depending on the site, cultivar and initial post-harvest stubble treatment. The third part of the paper is based on more detailed studies of persistence of seeds of six cultivars in Petri dishes and buried in 25 cm pots. This work confirmed that cultivars differed in their persistence, as Apex was confirmed as highly persistent, whereas Rebel was short-lived. There were inconsistencies in the response of cultivar Synergy between the Petri-dish and pot experiment, which need further study. This experiment also reinforced the conclusion of the initial field experiments that little seed loss occurs in the absence of cultivations. Appreciable numbers of rape seeds will persist up to 4 years, in normal cropping conditions and in the absence of cultivation one experiment has confirmed persistence for over 11 years.

Soil test phosphorus as affected by phosphorus budgets in two long-term field experiments in Germany

2018 ◽  
Vol 218 ◽  
pp. 158-170 ◽  
Author(s):  
Theresa Zicker ◽  
Sabine von Tucher ◽  
Mareike Kavka ◽  
Bettina Eichler-Löbermann
Keyword(s):  
Field Experiments ◽  
Soil Test ◽  
Phosphorus Budgets ◽  
Soil Test Phosphorus ◽  
Term Field

Soil organic carbon sequestration potential for Canadian Agricultural Ecoregions calculated using the Introductory Carbon Balance Model

2008 ◽  
Vol 88 (4) ◽  
pp. 451-460 ◽  
Author(s):  
M A Bolinder ◽  
O. Andrén ◽  
T. Kätterer ◽  
L -E Parent
Keyword(s):  
Biological Activity ◽  
Carbon Balance ◽  
Crop Production ◽  
Field Experiments ◽  
Balance Model ◽  
Agricultural Crop ◽  
Organic C ◽  
Soil Biological Activity ◽  
Sequestration Potential

The potential for storage of atmospheric CO2-C as soil organic C (SOC) in agroecosystems depends largely on soil biological activity and the quantity and quality of annual C inputs to soil. In this study we used the Introductory Carbon Balance Model (ICBM) approach driven by daily standard weather station data, specific soil properties and crop characteristics at the scale of Canadian agricultural ecoregions. The objectives were to calculate a climate-dependent soil biological activity parameter representative for annual agricultural crop production systems (re_crop) and to estimate the effect of fallow (re_fallow). These parameters are based on the daily product of soil temperature and stored water that influence biological activity in the arable layer, and are used to adjust the decomposition rates of the ICBM SOC pools. We also tested re_crop and re_fallow on SOC stock change data for different site and treatment combinations from long-term field experiments located in some of the ecoregions. An re_crop value of 0.95 for western ecoregions was on average 0.23 units lower than that of the eastern ecoregions, indicating a lower decomposition rate of SOC. Although the estimated annual C inputs to soil for small-grain cereals were on average ≈7.5% higher in the eastern ecoregions (305 vs. 285 g C m-2 yr-1), the overall results suggest that the western ecoregions would have a greater potential to maintain high SOC levels in the long term. However, these parameters varied between ecoregions and, consequently, the SOC sequestration potential was not always higher for the western ecoregions. The effect of fallow was on average ≈0.04, i.e., SOC decomposed slightly faster under fallow. Predictions for 24 out of 33 site and treatment combinations across Canada were significantly improved (P = 0.003), compared with a previous application with the ICBM that did not differentiate between crops and fallow. The methodology used here enabled us to examine regional differences in the potential for SOC sequestration as a balance between annual C inputs to soil and soil biological activity. Key words: Annual C inputs, climate, fallow, soil biological activity, agroecosystems

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