Increase In Aboveground Biomass Research Articles

Understanding the relationship between biomass production and water use of Populus tomentosa trees throughout an entire short-rotation

Understanding the relationship between tree production and water use, as well as the main environmental and plant-related drivers of water use, is crucial for the development of production prediction models and reliable water management strategies under different climatic conditions. However, the relation between tree water use and biomass production has never been assessed throughout the entire rotation for poplar trees. Meanwhile, it remains poorly understood how the transpiration driving factors of poplars will change with stand age. Therefore, we investigated the relationship between transpiration (E) and aboveground biomass (ABM), as well as the main drivers of E for 2- to 5-year-old (2016–2019) Populus tomentosa trees under three water treatments. The annual increase in ABM depended on annually accumulated E and their relationship could be fitted with a logistic curve in each growing season (R2 > 0.89). Throughout the whole rotation period, compared with the non-irrigated trees, full irrigation trees produced 59% more biomass with only 12% more E, while deficit irrigation trees attained 46% more biomass with 32% more E. The daily E had a strong exponential relationship with vapor pressure deficit (D) during years 3–5 of the rotation, and the asymptote of this relationship increased with tree age (1.6 kPa (2017), 2 kPa (2018), 2.5 kPa (2019)). The E was also strongly linearly correlated to solar radiation (Rs) for each year although with slightly weaker relationships than for D. Similar to other poplar species, P. tomentosa showed effective stomatal control on E. However, soil water content had almost no effect on E for all treatments, no matter which soil layer was considered. D and Rs were the major drivers of P. tomentosa transpiration during the growing season, even during drought periods, in the study region. Our findings will not only help to deepen the understanding of poplar water use characteristics and the underlying mechanisms, but also help to develop models for predicting the biomass production.

Below ground carbon inputs to soil via root biomass and rhizodeposition of field-grown maize and wheat at harvest are independent of net primary productivity

Below ground carbon (BGC) inputs to soil, i.e. root biomass and rhizodeposition carbon (C), are among the most important variables driving soil C dynamics in agroecosystems. Hence, increasing BGC inputs to deep soil is a proposed strategy to sequester C in the long term. As BGC inputs are inherently difficult to measure in the field, they are usually estimated from yield in order to supply soil C models with input data. While fertilization intensity considerably affects above ground biomass, its influence on BGC inputs is largely unclear, especially with respect to the subsoil. Therefore, we determined net root biomass and rhizodeposition C of field-grown maize and wheat at harvest in different farming systems (bio-organic, conventional) and fertilization treatments (zero, manure, mineral) along an intensity gradient in two Swiss long-term field trials. Plants in microplots were repeatedly pulse-labelled with 13C-CO2 throughout the growing seasons and shoots, roots, and soil to 0.75 m depth were sampled at harvest. Despite a strong increase of above ground biomass with increasing fertilization intensity, BGC inputs were similar among treatments on both sites irrespective of soil depth. However, the proportions of rhizodeposition C of BGC inputs averaged 54 to 63% and were, therefore, much larger than the widely adopted 40% for field-grown cereals. They increased with soil depth and were highest under sole organic fertilization. The shift in whole-plant C allocation towards above ground biomass with increasing fertilization intensity entailed 10% higher C allocation below ground in organic than conventional farming for both maize and wheat. Our findings imply that yield-independent values provide closer estimates for BGC inputs to soil of cereals in different farming systems than yield-based functions. We further conclude that fertilization has only little potential to alter absolute amounts of BGC inputs to deep soil in order to sequester C in the long term.

Estimation and dynamics of above ground biomass with very high resolution satellite images in Pinus pinaster stands

Biomass estimation is a tool for evaluating stands and forest dynamics. Traditional indirect methods use forest inventories and allometric functions at tree level to evaluate biomass at plot level, and an extrapolation method to assess an area. The goal of this study was the development of allometric functions for Pinus pinaster with crown horizontal projection derived from very high spatial resolution satellite images as an independent variable, as well as their application to the analysis of above ground biomass dynamics. The fitted functions show a good performance. The function used to estimate the above ground biomass per grid in 2004, 2007 and 2011 for the study area enable the evaluation of their temporal dynamics. From 2004 to 2007 it decreased in 90.5% of the study area, due to forest fires and cuts to control the pinewood nematode; from 2007 to 2011 increased in 45.6% and decreased in 51.6%, the latter corresponding to cuts to control the aforementioned disease. In 76.4% of the burnt areas, natural regeneration resulted in an increase of above ground biomass. The method's main advantages are the simultaneous evaluation of small or large areas and, when implemented in a GIS, it allows straightforward monitoring over a short period of time.

Allergen of the Month—Fringed Sagebrush

Artemisia species are important aeroallergen sources in both the Eastern and Western hemispheres. 1 Lewis W.H. Vinay P. Zenger V.E. Airborne and Allergenic Pollen of North America. Johns Hopkins University Press, Baltimore1983 Google Scholar , 2 Bassett I.J. Crompton C.W. Parmalee J.A. An atlas of airborne pollen grains and common fungus spores of Canada. Printing and Publishing, Supply and Services Canada, Hull, Quebec1978 Google Scholar , 3 Wodehouse R.P. Hayfever Plants. 2nd Ed. Hafner, New York1971 Google Scholar At least 19 native and introduced species are found within the United States. [1] Lewis W.H. Vinay P. Zenger V.E. Airborne and Allergenic Pollen of North America. Johns Hopkins University Press, Baltimore1983 Google Scholar Fringed sagebrush, A. frigida, is native to North America, ranging from the Yukon to New Brunswick, and southward through the western states into Mexico, where it is known as estafiata. 1 Lewis W.H. Vinay P. Zenger V.E. Airborne and Allergenic Pollen of North America. Johns Hopkins University Press, Baltimore1983 Google Scholar , 2 Bassett I.J. Crompton C.W. Parmalee J.A. An atlas of airborne pollen grains and common fungus spores of Canada. Printing and Publishing, Supply and Services Canada, Hull, Quebec1978 Google Scholar , 4 Dayton W.A. Range Plant Handbook. Dover Publications, Inc., New York1988 Google Scholar It is also found throughout the Siberian steppes, and is considered native to Eurasia as well, being the most widespread of all Artemisia species. 4 Dayton W.A. Range Plant Handbook. Dover Publications, Inc., New York1988 Google Scholar , 5 Morgan J.A. Milchunas D.G. LeCain D.R. West M. Mosier A.R. Carbon dioxide enrichment alters plant community structure and accelerates shrub growth in the shortgrass steppe. PNAS. 2007; 104: 14724-14729 Crossref PubMed Scopus (166) Google Scholar The species name derives from the cold bleak regions of eastern Siberia, where it was first described. [4] Dayton W.A. Range Plant Handbook. Dover Publications, Inc., New York1988 Google Scholar A. frigida will grow on a variety of sites, to over 11,000 feet (3353 m). Fringed sagebrush is exceedingly responsive to increased CO2 associated with climate change: a doubling of the ambient CO2 results in a 40-fold increase in above ground biomass and a 20-fold increase in ground cover from the shrub. [5] Morgan J.A. Milchunas D.G. LeCain D.R. West M. Mosier A.R. Carbon dioxide enrichment alters plant community structure and accelerates shrub growth in the shortgrass steppe. PNAS. 2007; 104: 14724-14729 Crossref PubMed Scopus (166) Google Scholar Spreading of A. frigida is also potentiated by having allelopathic effects, and inhibition of grass root and shoot growth has been shown. [6] Li X.F. Wang J. Xu W.B. Wang K. Allelopathic effects of Artemisia frigida on three Poaceae plants seed germination and seedling growth. Ying Yong Sheng Tai Xue Bao. 2010; 21: 1702-1708 PubMed Google Scholar Essential oil of A. frigida is fragrant, with high content of camphor and cineol, and has antiseptic and antioxidant properties. 4 Dayton W.A. Range Plant Handbook. Dover Publications, Inc., New York1988 Google Scholar , 7 Lopes-Lutz D. Alviano D.S. Alviano C.S. Kolodziejczyk P.P. Screening of chemical composition, antimicrobial and antioxidant activities of Artemisia essential oils. Phytochemistry. 2008; 69: 1732-1738 Crossref PubMed Scopus (427) Google Scholar

Use of Treated Wastewater as Fertilization and Irrigation Amendment in Pot-grown Processing Tomatoes

ABSTRACT Plants of tomato cultivar ‘TITANO M’ were grown under glasshouse conditions, in plastic pots filled with the upper (Ap, Soil A) and the underlying horizons (Bt, Soil B) of an Alfisol from central Greece in a randomized complete block design. Four treatments were utilized: no fertilization and irrigation with distilled water (C), irrigation with wastewater without fertilization (W), complete fertilization (110 kg N ha−1, 150 kg P2O5 ha−1, 150 kg K2O ha−1) and irrigation with distilled water (CF), complete fertilization and irrigation with wastewater (WF) each replicated four times. The results showed that wastewater significantly increased electrical conductivity (EC), exchangeable sodium percentage (ESP), exchangeable magnesium (Mg), and extractable zinc (Zn). A three-fold increase of above ground biomass (AGB) compared to C treatment was recorded in Soil A. Photosynthates allocation to AGB and water use efficiency (WUE) were promoted by effluent application. Wastewater could be a water source for agriculture under water limited conditions substituting partially for inorganic fertilization.

COMPARISON OF THE EFFECTS OF WET N DEPOSITION (NH4Cl) AND DRY N DEPOSITION (NH3) ON UK MOORLAND SPECIES

Increases in N deposition (wet and dry) have been associated with a decline in seminatural plant communities, adapted for growth on nutrient poor soils in the UK and Europe. The impacts of N deposition applied as either wet NH4+ or gaseous NH3 on vegetation (7 species) from acid moorland in SE Scotland were compared in a dose-response study. Wet N deposition at 0, 8, 16, 32, 64, 128 kg N ha-1 y-1 was applied as NH4C1, and dry deposition as gaseous NH3 (2, 6, 20, 50, 90 μg NH3 m-3) under controlled conditions in open-top chambers. A strong linear doseresponse relationship (p<0.05) was found between foliar N content in all seven plant species and applied NH4-N. However, in the NH3 treatment, only C. vulgaris and P. commune showed a significant response to increasing N additions. NH3 was found to increase the rate of water loss in Calluna in both autumn and winter by comparison with wet deposition. For Eriophorum vaginatum, the NH3 and NH4+ treatments showed significant N dose response relationships for biomass. A significant increase in above ground biomass, proportional to the added N, was found for Narthecium ossifragum when N was applied as NH3 compared to NH4+.

Deficit irrigation and nitrogen effects on maize in a Sahelian environment: II. Shoot growth, nitrogen uptake and water extraction

Maize growth in arid and semiarid regions is often limited by variation in the amount and frequency of irrigation or rainfall. Sub-optimal supply of nitrogen (N) may further curtail growth and development of the crop. Simultaneous optimization of these two inputs provides optimum conditions for crop growth and productivity. A maize ( Zea mays L.) crop was subjected to different periods of deficit irrigation and rates of N in the field on a medium-deep Tropudalf clay loam soil. Water deficit effects on shoot growth, N uptake and water extraction with varying level of N supply were analyzed to determine their inter-relationships. Water deficit was created by withholding irrigation at different stages of crop development. Increasing moisture stress resulted in progressively less leaf area, crop growth rate (CGR), plant height, shoot dry matter and harvest index. Mean increase in above ground biomass was 7.7 and 8.7 kg per mm of water used in the 1996/1997 and 1997/1998 seasons, respectively. Deficit irrigation stress indices (DISI) for above ground biomass when the crop was subjected to a 2 week stress was 11.0 and 20.1 compared to 4 week stress values of 3.2 and 16.5 in the 1996/1997 and 1997/1998, respectively, indicating greater stress the first season during vegetative growth. When deficit irrigation was increased to 8 weeks, DISI values were 34.1 and 39.8 for the respective seasons. Biomass production response to N in both years was quadratic; however, N response differed with irrigation level in both seasons. Highest biomass yield with no irrigation deficit was obtained at 120 kg N in 1996/1997 and at 160 kg N ha −1 in 1997. Nitrogen uptake was more dependent on applied N than water supply although N uptake decreased with greater water and N deficits. Water extraction was highest at the 120 and 160 kg N ha −1 rates with soil water deficit. This study showed that a maize crop differs in its ability to maintain LAI, CGR and above ground dry matter production at different levels of water deficit and N supply. The adaptive strategy of maize plants under vegetative water stress appears to be extended rooting depth and water extraction from the deeper soil profile, and simultaneous reduction in leaf area to decrease transpiration. Optimizing the inputs of water and N at the farm level would maximize biomass production and harvest index. This information can be useful to guide crop management strategy to enhance maize production in the irrigated perimeter of a Sahelian environment.

The Influence of Increasing Carbon Dioxide and Temperature on Competitive Interactions Between a C3 Crop, Rice (Oryza sativa) and a C4 Weed (Echinochloa glabrescens)

Many of the most troublesome weeds in agricultural systems are C4 plants. As atmospheric CO2 increases it is conceivable that competitive ability of these weeds could be reduced relative to C3 crops such as rice. At the International Rice Research Institute (IRRI) in the Philippines, rice (IR72) and one of its associated C4 weeds, Echinochloa glabrescens, were grown from seeding to maturity using replacement series mixtures (100:0, 75:25, 50:50, 25:75, and 0:100, % rice:%weed) at two different CO2 concentrations (393 and 594 μL L-1) in naturally sunlit glasshouses. Since increasing CO2 may also result in elevated growth temperatures, the response of rice to each CO2 concentration was also examined at daylnight temperatures of 27/21 and 37/29�C. At 27/21�C, increasing the CO2 concentration resulted in a significant increase in above ground biomass (+47%) and seed yield (+55%) of rice when averaged over all mixtures. For E. glabrescens, the C4 species, no significant effect of CO2 concentration on biomass or yield was observed. When grown in mixture, the proportion of rice biomass increased significantly relative to that of the C4 weed at all mixtures at elevated CO2. Evaluation of changes in competitiveness (by calculation of plant relative yield (PRY) and replacement series diagrams) of the two species demonstrated that, at elevated CO2, the competitiveness of rice was increased relative to that of E. glabrescens. However, at the higher growth temperature (37/29�C), growth and reproductive stimulation of rice by elevated CO2 was reduced compared to the lower growth temperature. This resulted in a reduction in the proportion of rice:weed biomass present in all mixtures relative to 27/21�C and a greater reduction in PRY in rice relative to E. glabrescens. Data from this experiment suggest that competitiveness could be enhanced in a C3 crop (rice) relative to a C4 weed (E. glabrescens) with elevated CO2 alone, but that simultaneous increases in CO2 and temperature could still favour a C4 species.