Effects of water stress on water use efficiency and water balance components of <Emphasis Type="Italic">Hippophae rhamnoides</Emphasis> and <Emphasis Type="Italic">Caragana intermedia</Emphasis> in the soil–plant–atmosphere continuum

Hippophae rhamnoides (Sea buckthorn) and Caragana intermedia (Intermediate peashrub), which are nitrogen-fixing and perennial temperate shrubs, are extensively used in the agroforestry systems in the loess areas of China. In this study, artificially controlled water gradient experiments were carried out with both shrubs, based on four levels of water supply (normal precipitation, slight drought, drought, and extreme drought). The results showed significant impacts of drought on net photosynthesis rate, biomass accumulation, and biomass allocation in both species. Water use efficiency (WUE) varied with different species, scales, and water stress intensities. WUE at the leaf scale (WUEi) was highest under moderate water stress, while the WUE at the community scale (WUEb) decreased with increasing water stress. We observed alteration in the diel and seasonal transpiration of both species in response to water stress. The night-time transpiration accounted for a small but significant proportion of the water balance, and its importance tended to increase with increasing drought. Both species experienced water deficits under all treatments. Soil moisture of H. rhamnoides declined more severely than that of C. intermedia. The ratio of transpiration to evapotranspiration (T/ET) ranged from 50 to 80% for both species in the growing season. The T/ET and WUEi of H. rhamnoides were comparatively smaller under severe water stress but increased under moist conditions. Our data suggest that H. rhamnoides uses water resources more efficiently under favorable water conditions, and C. intermedia shows competitive advantages under drought conditions. Moreover, possible strategies to maintain water balance in the water-limited agroforestry systems are discussed.     

Quantitative genetics of cold hardiness and growth in <Emphasis Type="Italic">Eucalyptus</Emphasis> as estimated from <Emphasis Type="Italic">E.</Emphasis><Emphasis Type="Italic">urophylla</Emphasis> × <Emphasis Type="Italic">E. tereticornis</Emphasis> hybrids

Interspecific hybrids of Eucalyptus urophylla S. T. Blake × E. tereticornis Smith were used for quantitative genetic analysis of cold hardiness (CH) and growth traits height (H), diameter at breast height (D) and volume (V) at 0.5, 1.5, 2.5 and 4 years of age. The effect of E. tereticornis male variance was significant (P < 0.05) for CH as well as 2.5- and 4-year-old growth except for H ₄, and E. urophylla female × E. tereticornis male interaction was significant for 0.5- and 1.5-year-old growth and CH except for CH _0.5, whereas E. urophylla female effect was not significant for the majority of traits analyzed. Both additive and dominance gene action were present in the genetics of all the traits measured at most ages, indicating that those traits may be improved by hybrid breeding. The σ _D ²/σ _A ² ratios tended to decline after 1.5 years of age in CH and growth traits, implying that breeding value predictions derived from older performance might be more reliable. Estimates of narrow-sense heritability (h ² ) for CH and growth ranged from 0.03 ± 0.05 to 0.28 ± 0.13, depending on trait and age. Additive genetic correlations between CH and V were 0.28 ± 0.48 and 0.69 ± 0.30 at ages 1.5 and 2.5, respectively, suggesting that selection for growth would cause a favorable increase in cold hardiness in E. urophylla × E. tereticornis hybrids.     

Two-year dynamics of foliage labelling in 8-year-old <Emphasis Type="Italic">Pinus pinaster</Emphasis> trees with <Superscript>15</Superscript>N, <Superscript>26</Superscript>Mg and <Superscript>42</Superscript>Ca—simulation of Ca transport in xylem using an upscaling approach

• Introduction   

Atmospheric deposition is an important input of major nutrients into forest ecosystems. The long-term goal of this work was to apply stable isotope methodology to assess atmospheric nutrient deposition in forest systems.     

Effect of silvicultural treatments on growth,fertility and capsule traits in seedling seed orchards of <Emphasis Type="Italic">Eucalyptus camaldulensis</Emphasis> and <Emphasis Type="Italic">E. tereticornis</Emphasis>

The effects of nutritional treatments and the flowering promoter Paclobutrazol™ on tree growth and fertility were studied in unpedigreed seedling seed orchards (SSOs) of Eucalyptus camaldulensis and E. tereticornis at two locations in southern India. At Pudukkottai, a semi-arid site in Tamil Nadu State, five treatments were applied: (1) untreated control, (2) nitrogen (two doses of urea at 217 g N/tree), (3) nitrogen plus phosphorus (two doses of 312 g single superphosphate), potassium (two doses of 83 g muriate of potash) and trace elements (two doses of 10 g sodium borate and 25 g zinc sulphate), (4) pollarding trees at 4 m height with application of N, P, K and trace elements, (5) drenching with the flowering promoter Paclobutrazol (0.25 ml active ingredient per cm of stem girth) along with N, P, K and trace elements. At Panampalli, a higher-rainfall site in Kerala State, only treatments 1, 2 and 3 were applied. Four replicates of treatment plots sized 18 m × 18 m, with 22–32 trees per plot were set up in each orchard in randomized complete block designs. Untreated plots of E. camaldulensis and E. tereticornis at Pudukkottai displayed 12 and 21% fertile trees, respectively, in the first year of monitoring, while at Panampally the percentage of fertile trees in untreated E. camaldulensis plots was higher at 72%, and that of E. tereticornis similar at 23%. Both species attained greater stem diameter at breast height at age 9 years at the higher-rainfall location but there was no significant impact of fertilizer application on 9-year diameter at either site. Diameter was reduced by pollarding and Paclobutrazol application at Pudukkottai. Only Paclobutrazol produced a significant increase in fertility in both species for four successive years, increasing the percentage of fertile trees to 59 and 71%, respectively, for E. camaldulensis and E. tereticornis 1 year after application. The number of capsules produced per tree also increased significantly with Paclobutrazol application, although the difference was comparatively less by the fourth year. The number of capsules per umbel did not differ significantly between locations, whereas the germination rate varied between treatments although no consistent trends were observed.     

Fagacées: a tree-centered growth and yield model for sessile oak (<Emphasis Type="Italic">Quercus petraea</Emphasis> L.) and common beech (<Emphasis Type="Italic">Fagus sylvatica</Emphasis> L.)

• Introduction  

Fagacées is a growth model that has been developed for pure Oak or Beech stand management in even-aged high forests and coppice with standards forests. It has been calibrated for the plain forests of northern France.     

Genetic parameters for growth and wood chemical properties in <Emphasis Type="Italic">Eucalyptus urophylla</Emphasis> × <Emphasis Type="Italic">E. tereticornis</Emphasis> hybrids

Key message

Growth and wood chemical properties are important pulpwood traits. Their narrow-sense heritability ranged from 0.03 to 0.49 in Eucalyptus urophylla × E. tereticornis hybrids, indicating low to moderate levels of genetic control. Genetic correlations were mostly favorable for simultaneous improvement on growth and wood traits. Additive and non-additive genetic effects should be considered in making a hybrid breeding strategy.

Context

Eucalypt hybrids are widely planted for pulpwood production purposes. Genetic variations and correlations for growth and wood chemical traits remain to be explored in Eucalyptus interspecific hybrids.

Aims

Our objectives were to clarify the heritability of growth and wood chemical traits and determine the genetic correlations between traits and between trials in E. urophylla × E. tereticornis hybrids.

Methods

Two trials of 59 E. urophylla × E. tereticornis hybrids derived from an incomplete factorial mating design were investigated at age 10 for growth (height and diameter) and wood chemical properties (basic density, cellulose content, hemi-cellulose content, lignin content, and syringyl-to-guaiacyl ratio). Mixed linear models were used to estimate genetic parameters.

Results

Narrow-sense heritability estimates were 0.13?0.22 in growth and 0.03?0.49 in wood traits, indicating low to moderate levels of additive genetic control. Genetic correlations were mostly positively significant for growth with basic density and cellulose content but negatively significant with hemi-cellulose and lignin contents, being favourablefavorable for pulpwood breeding purpose. Type-B correlations between sites were significant for all the traits except diameter and lignin content.

Conclusion

Hybrid superiority warrants the breeding efforts. An appropriate breeding strategy should be able to capture both additive and non-additive genetic effects.

     

The effects of phenolic acid on nitrogen metabolism in <Emphasis Type="Italic">Populus</Emphasis> × <Emphasis Type="Italic">euramericana</Emphasis> ‘Neva’

The declines in soil fertility and productivity in continuously cropped poplar plantations are related to phenolic acid accumulation in the soil. Nitrogen is a vital life element for poplar and whether the accumulation of phenolic acid could influence nitrogen metabolism in poplar and thereby hinder continuous cropping is not clear. In this study, poplar cuttings of Populus × euramericana ‘Neva’ were potted in vermiculite, and phenolic acids at three concentrations (0X, 0.5X and 1.0X) were added according to the actual content (1.0X) in the soil of a second-generation poplar plantation. Each treatment had eight replicates. We measured gas exchange parameters and the activities of key enzymes related to nitrogen metabolism in the leaves. Leaf photosynthetic parameters varied with the concentration of phenolic acids. The net photosynthetic rate (P_N) significantly decreased with increasing phenolic acid concentration, and non-stomatal factors might have been the primary limitation for P_N. The activities of nitrate reductase (NR), glutamine synthetase (GS) and glutamate synthase (GOGAT), as well as the contents of nitrate nitrogen, ammonium nitrogen, and total nitrogen in the leaves decreased with increasing phenolic acid concentration. This was significantly and positively related to P_N (P < 0.05). The low concentration of phenolic acids mainly affected the transformation process of NO₃^? to NO₂^?, while the high concentration of phenolic acids affected both processes, where NO₃^? was transferred to NO₂^? and NH₄⁺ was transferred to glutamine (Gln). Overall, phenolic acid had significant inhibitory effects on the photosynthetic productivity of Populus × euramericana ‘Neva’. This was probably due to its influence on the activities of nitrogen assimilation enzymes, which reduced the amount of amino acids that were translated into protein and enzymes. Improving the absorption and utilization of nitrogen by plants could help to overcome the problems caused by continuous cropping.     

Can drought tolerance of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> (L.) <Emphasis Type="Italic">Karst</Emphasis>.) be increased through thinning?

To investigate whether drought tolerance of individual trees can be increased through the provision of more growing space, trees from a thinning experiment were analysed for reductions in radial growth during drought years and their subsequent recovery. Tree-ring widths were quantified on increment cores as well as stem discs of 32 trees from stands of a thinning trial established in 1974 in 27-year-old spruce stands in the Alpine Foreland of Southwest Germany. Three different thinning regimes of the trial were selected for this study: unthinned control (8 trees), moderate (13 trees) and heavy thinning (11 trees) intensities. All trees sampled were of a co-dominant to dominant canopy status. The standardisation of growth data was carried out using the software program ARSTAN (University of Arizona). For the year 1976—a widespread and severe drought year in Germany—we found year ring widths were not reduced compared to those of the pre-drought years for all treatments. However, we observed the formation of false year rings and resin ducts for this year in all trees investigated. The drought events in 1992 and 2003 led to severe growth depressions in the year of the drought event in all trees, regardless of previous thinning regimes. However, the resilience—the recovery of basal area growth in subsequent years—was significantly more rapid in trees from heavily thinned stands, even if the drought event occurred more than 10 years after the last thinning intervention. This indicates a shorter stress period for trees with more growing space, which may reduce the susceptibility to secondary pathogens or pest species such as bark beetles.     

Differences in leaf functional traits between red and green leaves of two evergreen shrubs <Emphasis Type="Italic">Photinia</Emphasis> × <Emphasis Type="Italic">fraseri</Emphasis> and <Emphasis Type="Italic">Osmanthus fragrans</Emphasis>

Leaf functional traits are adaptations that enable plants to live under different environmental conditions. This study aims to evaluate the differences in leaf functional traits between red and green leaves of two evergreen shrubs Photinia × fraseri and Osmanthus fragrans. Specific areas of red leaves are higher than that of green leaves in both species. Thus, the material investment per unit area and per lamina of red leaves is significantly lower than that of green leaves, implying an utmost effort of red leaves to increase light capture and use efficiency because of their low leaf-chlorophyll concentration. The higher petiole length of green leaves compared with that of red leaves indicates that adult green leaves may have large fractional biomass allocation to support the lamina structures in capturing light with maximum efficiency and obtaining a high growth rate. The high range of the phenotypic plasticity of leaf size, leaf thickness, single-leaf wet and dry weights, and leaf moisture of green leaves may be beneficial in achieving efficient control of water loss and nutrient deprivation. The high range of phenotypic plasticity of leaf chlorophyll concentration of red leaves may be advantageous in increasing resource (especially light) capture and use efficiency because this leaf type is juvenile in the growth stage and has low leaf-chlorophyll concentration.     

Does the persistence of sweet chestnut depend on cultural inputs? Regeneration,recruitment, and mortality in <Emphasis Type="Italic">Quercus</Emphasis>- and <Emphasis Type="Italic">Castanea</Emphasis>-dominated forests

Key message

Quercus secondary forests show a gradual transition toward mixed forests, with sweet chestnut ( Castanea sativa ) becoming increasingly abundant in the western Spanish Central System. Additionally, in chestnut-dominated stands, it shows a certain resistance to competitive displacement by Quercus pyrenaica . Our results partially refute the traditional view that C. sativa is unable to recruit in the absence of cultural inputs.

Context

Sweet chestnut, Castanea sativa, is a component of European broadleaf forests and is one of the most managed trees. Due to a reduction in cultural inputs, chestnut-dominated stands tend to be invaded by other species, and it is unclear how chestnut is able to persist in natural mixed forests.

Aims

Our work aimed to identity the main factors that limit the establishment of C. sativa and to analyze the recruitment and mortality processes of C. sativa trees.

Methods

The age, growth ring patterns, regeneration density, and the spatial structure of trees and saplings in 11 plots in the Spanish Central System were analyzed.

Results

Chestnut seedling density increased with C. sativa basal area, but transition toward the sapling stage appeared limited owing to light availability. In Quercus pyrenaica secondary forests, sparse canopies did not constrain chestnut regeneration, and in old chestnut stands, C. sativa showed a certain resistance to competitive displacement. By contrast, mixed young coppices showed a high mortality, most likely due to competition with other vigorous resprouters.

Conclusion

Quercus secondary forests showed a gradual transition toward mixed forests with sweet chestnut becoming increasingly more abundant. In old stands, C. sativa is likely to persist under a gap-phase mode of regeneration. Our results partially refute the traditional view that C. sativa is unable to recruit in the absence of cultural inputs.

     

Effect of major inorganic nutrients on <Emphasis Type="Italic">β</Emphasis>-thujaplicin production in a suspension culture of <Emphasis Type="Italic">Cupressus lusitanica</Emphasis> cells

 The optimum conditions for β-thujaplicin production in a Cupressus lusitanica cell suspension culture were investigated. The conditions required for β-thujaplicin production were clearly different from the conditions for cell growth. The initial phosphate concentration and pH did not affect β-thujaplicin production. A total nitrogen source concentration higher than 3.2 mM suppressed production due to the presence of the ammonium ion. β-Thujaplicin production was observed at 95 mg/l without adding the ammonium ion to the medium. Strict control of major inorganic nutrients was not necessary to produce β-thujaplicin. This finding seems to be favorable for future automated production of β-thujaplicin in commercial cell culture plants.     

Initial recovery of compacted soil—planting and technical treatments decrease CO<Subscript>2</Subscript> concentrations in soil and promote root growth

Key message

The combination of technical treatments and planting of alder trees in a compacted forest soil improves the circulation of air and water through the pore system. This leads to decreases in CO ₂ concentrations and increases in root growth in the soil. Both are indicative of an initial recovery of soil structure.

Context

The compaction of forest soils, caused by forest machinery, has as a principal consequence: the destruction of soil structure and thus the reduction of the soil aeration status. Thus, the gas exchange between soil and atmosphere is reduced and the depth propagation of roots is limited, resulting in the shortage of water and nutrient supplies for trees.

Aims

This research aimed at detecting the first stages of recovery of soil structure in a compacted forest soil, which was treated with a combination of techniques (i.e., planting tree species, mulching, addition of lime), which could presumably accelerate the regeneration of soil structure.

Methods

The variation of CO₂ concentrations and the dynamics of root growth were repeatedly measured. Linear mixed models were developed in order to test the effects of the treatments and the planting of trees on soil aeration, as well as to identify the influence of the different environmental effects on CO₂ concentration in soil.

Results

The planting of root-active trees showed significant effects on decreases in CO₂ concentrations. However, during the short-term observation, some negative effects occurred especially for the mulched sites. Nevertheless, all applied technical treatments promoted an improved soil aeration and a higher root growth compared to untreated sites which points to an initial enhanced recovery of soil structure. Pronounced seasonal and interannual variations of soil respiration were highly influenced by soil temperature and soil water content variations.

Conclusion

An initial regeneration of soil structure is indicated by distinct changes of the soil aeration status. This regeneration is partially enhanced by the applied treatments. The quantitative potential of the regeneration techniques needs a longer observation period for mid- and long-term soil recoveries.

     

Conjugation of δ-endotoxin from <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> with abamectin of <Emphasis Type="Italic">Streptomyces avermitilis</Emphasis> as a new type of biocide,GCSC-BtA,for control of agricultural insect pests

Conjugation of δ-endotoxin from Bacillus thuringiensis with abamectin, a toxin of Streptomyces avermitilis, was carried out to form a new type of biocide, GCSC-BtA based on “Germany-China Scientific Cooperation” research, for the control of agricultural insect pests. The strategy for biochemical linkage was designed by conjugating an amino group in B.t. protoxin with a carboxyl group in carboxylated abamectin under the treatment of conjugator EDC [1-Ethyl-3-(3-dimethylaminopropyl carbodiimide Hydrochloride)]. The formation of B.t. protoxin was processed by solubilizing B.t. crystal in 25?mM dithiothreitol (DTT) at 37?°C for 2?h. The carboxylated abamectin was formed by carboxylating the NaH-activated abamectin with 10?mg/ml butyric anhydride at 111?°C in a water-circumfluent condensation device for 2?h. The conjugating reaction, consisting of 5?mg/ml B.t. protoxin, 10?mg/ml carboxylated abamectin and 19.17?mg/ml EDC, was successfully conducted at room temperature for 24?h. Significant differences were found between pure abamectin, carboxylated abamectin and the conjugated BtA by means of UV-photo absorptions recorded at wavelengths 354, 438, 518, 600?nm (P?<?0.01). LT₅₀ of the conjugated GCSC-BtA to the 3^rd instar larvae of Plutella xylostella (L.) (Lep., Plutellidae) was 35.27 μg a.i./ml, about 62?% and 76?% of that caused by the B.t. protoxin and the caxboxylated abamectin, respectively. The conjugated GCSC-BtA caused 87.14?% mortalities in larvae of P. xylostella, 93.75?% in adult Myzus persicae (Sulzer) (Hom., Aphididae) and 89.33?% in adult Phyllotreta vittata Fabricius (Col., Chrysomelidae) as compared to 48.33?% by the B.t. crystal only in P. xylostella. The symptoms caused by conjugated GCSC-BtA in the 3^rd instar of P. xylostella were black color in the head part and white-yellow in the abdomen of dead larvae, which differed from the black color or the white-yellow all along the body caused by either the B.t. crystal or the abamectin, respectively. It was concluded that the conjugated GCSC-BtA biocide had a broader host spectrum and a faster killing speed than either the B.t. crystal or abamectin alone for the control of agricultural pests.     

Influence of stem rot pathogen <Emphasis Type="Italic">Fomitiporia</Emphasis> sp. on “Sanbu-sugi” cultivar of the Japanese cedar <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>

An unidentified Fomitiporia sp. causes severe white-rot on stems of a cultivar “Sanbu-sugi” of the Japanese cedar, Cryptomeria japonica. The influence of the fungus on tree health and wood properties was determined. Bark from dead branches and xylem from living branches contained more glucose than bark from living branches and xylem from dead branches. Tree heights at which annual rings were disconnected were 2, 4 and 6 m at ages 37, 15 and 24 years old, respectively. The pH values of damaged parts were lower than those of non-damaged parts, and the damaged parts were clearly identified using bromocresol green solution. Weight loss of sapwood during 60 days of fungal degradation was 1.4 %, which was less than that by a saprophyte, Trametes versicolor. The amount of polyphenols in the heartwood from damaged tree stems was less than that from non-damaged stems. Degraded parts were less stiff than the non-degraded sapwood as measured with a wood-decay tester, Pilodyn. Our observations indicate that damaged stems are chemically and physically inferior to non-damaged stems.     

Furfural–biochar-based formulations show synergistic and potentiating effects against <Emphasis Type="Italic">Meloidogyne incognita</Emphasis> in tomato

The nematicidal activity of furfural, biochar and urea on plant-parasitic nematodes is rather well documented and approved; however, there is no information about combination treatment with those anti-nematode agents. We tested the nematicidal effect of combinations that paired furfural and biochar (F₀B, F_2.5B, F₅B and F₁₀B) or biochar-coated urea (F₀BCU, F_8.25BCU, F_16.5BCU and F₃₃BCU) to the root-knot nematode, Meloidogyne incognita (RKN) in the absence and presence of tomato plant, and characterized their possible mode of action. After biochar or BCU being paired with furfural, the accompanying effect of FB or FBCU, at all their application rates, resulted in superior control of RKN to that obtained when each component was applied individually. All applied levels of furfural–biochar-based formulations significantly inhibited RKN criteria compared to untreated control. Specifically, the FBCU formulation showed more synergistic interactions and greater nematicidal activity than FB on RKN. Nevertheless, the potentiating effect was the most common interaction between furfural and biochar with FB formulations on RKN. Despite their nematicidal activity, the applied furfural–biochar-based formulations were favorable to tomato growth and free-living nematodes when containing furfural at rates <1.0 g kg^?1 soil. In SEM study, the cuticle surface of J ₂ incubated in FBCU extracts for 12 h lost its normal aspect showing crimped appearance with distorted anus. In conclusion, the FBCU combination could be a sound alternate method of RKN control as it may reduce the cost of individual application of its inner components and thereby increase the net profit of economic crops.     

Is root nutrient uptake a modular function? A test using <Emphasis Type="Italic">Solidago canadensis</Emphasis>

Plant roots have been recognized to be modular, and a third order root cluster has been proposed to be the basic root module unit based upon the life cycle. This experiment examines root modularity of the nutrient-uptake function using stable isotope ¹⁵N. Solidago canadensis root clusters of second or third orders—from the same third or fourth order roots, respectively—were treated with ¹⁵NH ₄ ¹⁵ NO₃, NH₄NO₃, and de-ionized water for 15 and 180 min. The δ¹⁵N values of the root clusters were then analyzed and compared. The δ¹⁵N values of ¹⁵N-treated root clusters of both second and third orders were hundreds of times higher than that of the ¹⁵N untreated root clusters. However, the differences of the δ¹⁵N values among ¹⁵N untreated root clusters (though expressed some significant variations), did not indicate the ¹⁵N shared by the sister root clusters came from a common higher-order root. These results demonstrated functional modularity of root nutrient uptake, revealed a second order root, perhaps even a first order root to be a base module unit in terms of root nutrient uptake. The results also suggested that the concept of root modularity is function-specific. This experiment further revealed the importance of treatment timing in stabilizing the internal ¹⁵N/¹⁴N ratio in roots and avoiding top-down transportation of ¹⁵N back into roots to secure unbiased measurements.     

Enzymatic saccharification of water-soluble portion after hot-compressed water treatment of Japanese beech with xylanase and <Emphasis Type="Italic">β</Emphasis>-xylosidase

Enzymatic saccharifications of the hydrolysate collected as the water-soluble (WS) portion after hot-compressed water (HCW) treatment of Japanese beech with xylanase and β-xylosidase were performed to investigate the hydrolytic properties of these enzymes. The WS portions with different molecular weight distributions and initial concentrations of xylooligosaccharides were prepared as substrates, one of which contained mainly smaller xylooligosaccharides [degree of polymerization (DP) = 2 or 3], while the other contained larger xylooligosaccharides (DP ≥ 4). The highest xylose recovery was obtained from both of the WS portions treated with β-xylosidase rather than with xylanase. This suggests that β-xylosidase could have a higher activity than xylanase toward larger xylooligosaccharides (DP ≥ 4) as well as smaller xylooligosaccharides (DP = 2 or 3) recovered from HCW treatment. As a result, the use of β-xylosidase was found to be effective for saccharifi cation of the WS portion, even with a short reaction time for the HCW treatment.     

Changes of soil chemistry,stand nutrition,and stand growth at two Scots pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.) sites in Central Europe during 40 years after fertilization,liming, and lupine introduction

Long-term (40 years) effects of two soil amelioration techniques [NPKMgCa fertilization + liming; combination of PKMgCa fertilization, liming, tillage, and introduction of lupine (Lupinus polyphyllus L.)] on chemical topsoil properties, stand nutrition, and stand growth at two sites in Germany (Pfaffenwinkel, Pustert) with mature Scots pine (Pinus sylvestris L.) forest were investigated. Both sites are characterized by base-poor parent material, historic N and P depletion by intense litter-raking, and recent high atmospheric N input. Such sites contribute significantly to the forested area in Central Europe. Amelioration resulted in a long-term increase of pH, base saturation, and exchangeable Ca and Mg stocks in the topsoil. Moreover, significant losses of the forest floor in organic carbon (OC) and nitrogen stocks, and a decrease of the C/N ratio in the topsoil were noticed. The concentrations and stocks of OC and N in the mineral topsoil increased; however, the increases compensated only the N, but not the OC losses of the forest floor. During the recent 40 years, the N nutrition of the stands at the control plots improved considerably, whereas the foliar P, K, and Ca concentrations decreased. The 100-fascicle weights and foliar concentrations of N, P, Mg, and Ca were increased after both amelioration procedures throughout the entire 40-year period of investigation. For both stands, considerable growth acceleration during the recent 40 years was noticed on the control plots; the amelioration resulted in an additional significant long-term growth enhancement, with the NPKMgCa fertilization liming + being more effective than the combination of PKMgCa fertilization, liming, tillage, and introduction of lupine. The comprehensive evaluation of soil, foliage, and growth data revealed a key relevance of the N and P nutrition of the stands for their growth, and a change from initial N limitation to a limitation of other growth factors (P, Mg, Ca, and water).     

What factors influence the stem taper of <Emphasis Type="Italic">Eucalyptus</Emphasis>: growth,environmental conditions,or genetics?

• Introduction   

Stem taper equations have been widely used for volume estimation to varied top diameter limits or for biomass calculations. However, their main drawback is that specific calibration is often necessary for each species or clone, and accounting for genetic and environmental effects is often a challenge.     

Lethal and sub-lethal effects from short-term exposure of <Emphasis Type="Italic">Rhyzopertha dominica</Emphasis> on wheat treated with Storicide II<Superscript>®</Superscript>

Hard red winter wheat was treated at 0 (untreated control), 25, 50, 75, and 100% of the label rate of the insecticide Storicide II ^® , which is chlorpyrifos-methyl and deltamethrin applied at label rates of 3 and 0.5 ppm, respectively. Paired male and female Rhyzopertha dominica F., the lesser grain borer, were exposed at 27°C and 60% RH on wheat treated at each of the five rates above for 2, 4, 8, 16, or 32 h, and then transferred to untreated wheat and held for 1 week at the same environmental conditions. After this 1-week holding period, the parental adults were removed, mortality was assessed, and the wheat was then held for 7 weeks at the same environmental conditions to determine progeny production. As the concentration and exposure interval increased, mortality of both sexes approached 100%, but at the intermediate concentration–time combinations male mortality was greater than female mortality. Progeny production also decreased with increasing concentration of Storicide II^® as the exposure time increased, with non-linear patterns of decrease at the lower concentrations and time combinations and linear decline at the higher levels of concentration and time. Results seem to indicate greater susceptibility of males to Storicide II^®, and also show delayed parental mortality from the insecticide exposure and sub-lethal effects of reduced progeny production.