scholarly journals Large herbivore impact on plant biomass along multiple resource gradients in the Serengeti

2021 ◽  
Author(s):  
Neha Mohanbabu ◽  
Mark E. Ritchie
Keyword(s):  
Plant Biomass ◽  
P Availability ◽  
Large Herbivore ◽  
Resource Gradients ◽  
Plant Nitrogen ◽  
Plant Resource ◽  
Exclosure Experiment ◽  
Herbivore Impact ◽  
Herbivore Consumption ◽  
Multiple Resource

AbstractHerbivores form an important link in the transfer of energy within a food web and are strongly influenced by bottom-up trophic cascades. Current hypotheses suggest that herbivore consumption and impact on plants should scale positively with plant resource availability. However, depending on the effect of resources on plant quantity and quality, herbivore impact may vary with different types of resources. We test four alternative hypotheses for the relationship between plant biomass, herbivore impact on plant biomass, and plant resource gradients, each based on how resources might affect plant abundance and quality to herbivores. We measured plant biomass for four non-consecutive years in a long-term grazing exclosure experiment in the Serengeti National Park that includes seven sites that vary substantially in rainfall and soil and plant nitrogen (N) and phosphorus (P). Our data supported the hypothesis that herbivore impact is controlled by plant quality, in this case driven by plant P, as herbivore effects on biomass decreased with higher rainfall but increased with greater plant P, but not N content. To our knowledge, this is the first experimental study to indicate that wild mammalian herbivory is associated with P availability rather than N. Our results suggest that P, in addition to water and N, may play a more important role in driving trophic interactions in terrestrial systems than previously realized.

scholarly journals Termite mound cover and abundance respond to herbivore-mediated biotic changes in an African savanna

2021 ◽  
Author(s):  
Grace Charles ◽  
Corinna Riginos ◽  
Kari Veblen ◽  
Duncan Kimuyu ◽  
Truman Young
Keyword(s):  
Plant Biomass ◽  
Ecosystem Engineers ◽  
Tree Density ◽  
Herbaceous Plant ◽  
Ecosystem Structure ◽  
Termite Mound ◽  
Termite Mounds ◽  
Large Herbivore ◽  
Exclosure Experiment ◽  
And Function

Both termites and large mammalian herbivores (LMH) are savanna ecosystem engineers that have profound impacts on ecosystem structure and function. Both of these savanna engineers modulate many common and shared dietary resources such as woody and herbaceous plant biomass, yet few studies have addressed how they impact one another. In particular, it is unclear how herbivores may influence the abundance of long-lived termite mounds via changes in termite dietary resources such as woody and herbaceous biomass. While it has long been assumed that abundance and areal cover of termite mounds in the landscape remains relatively stable, most data are observational, and few experiments have tested how termite mound patterns may respond to biotic factors such as changes in large herbivore communities. Here, we use a broad tree density gradient and two landscape-scale experimental manipulations—the first a multi-guild large herbivore exclosure experiment and the second a tree removal experiment– to demonstrate that patterns in termite mound abundance and cover are unexpectedly dynamic. Termite mound abundance, but not areal cover not significantly, is positively associated with experimentally controlled presence of cattle, but not wild mesoherbivores (15-1000 kg) or megaherbivores (elephants and giraffes). Herbaceous productivity and tree density, termite dietary resources that significantly affected by different LMH treatments, are both positive predictors of termite mound abundance. Experimental reductions of tree densities are associated with lower abundances of termite mounds. These results reveal a richly interacting web of relationships among multiple savanna ecosystem engineers and suggest that termite mound abundance and areal cover is intimately tied to herbivore-driven resource availability.

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ ДИНАМИКИ МИНЕРАЛЬНОГО ПИТАНИЯ РАСТЕНИЙ В СИСТЕМЕ «УДОБРЕНИЕ-ПОЧВА-РАСТЕНИЕ»

2020 ◽  
Vol 65 (6) ◽  
pp. 1219-1229
Author(s):  
В.А. Четырбоцкий ◽  
◽  
А.Н. Четырбоцкий ◽  
Б.В. Левин ◽  
◽  
...  
Keyword(s):  
Experimental Data ◽  
Temporal Dynamics ◽  
Plant Biomass ◽  
Environmental Parameters ◽  
Parametric Identification ◽  
Agricultural Crop ◽  
Parameter System ◽  
Plant Nitrogen ◽  
Rhizosphere Microorganisms ◽  
Nitrogen Phosphorus

A numerical simulation of the spatial-temporal dynamics of a multi-parameter system is developed. The components of this system are plant biomass, mobile and stationary forms of mineral nutrition elements, rhizosphere microorganisms and environmental parameters (temperature, humidity, acidity). Parametric identification and verification of the adequacy of the model were carried out based on the experimental data on the growth of spring wheat «Krasnoufimskaya-100» on peat lowland soil. The results are represented by temporal distributions of biomass from agricultural crop under study and the findings on the content of main nutrition elements within the plant (nitrogen, phosphorus, potassium). An agronomic assessment and interpretation of the obtained results are given.

scholarly journals Cultivar-Dependent Responses in Plant Growth, Leaf Physiology, Phosphorus Use Efficiency, and Tuber Quality of Potatoes Under Limited Phosphorus Availability Conditions

2021 ◽  
Vol 12 ◽  
Author(s):  
Leangsrun Chea ◽  
Ana Meijide ◽  
Catharina Meinen ◽  
Elke Pawelzik ◽  
Marcel Naumann
Keyword(s):  
Tuber Yield ◽  
Plant Biomass ◽  
P Uptake ◽  
Tuber Quality ◽  
P Availability ◽  
Plant Tolerance ◽  
P Deficiency ◽  
Leaf Physiology ◽  
Use Efficiency

The limited availability of phosphorus (P) in soils causes a major constraint in the productivity of potatoes, which requires increased knowledge of plant adaptation responses in this condition. In this study, six potato cultivars, namely, Agria, Lady Claire, Milva, Lilly, Sieglinde, and Verdi, were assessed for their responses on plant growth, leaf physiology, P use efficiency (PUE), and tuber quality with three P levels (Plow, Pmed, and Phigh). The results reveal a significant variation in the cultivars in response to different P availabilities. P-efficient cultivars, Agria, Milva, and Lilly, possessed substantial plant biomass, tuber yield, and high P uptake efficiency (PUpE) under low P supply conditions. The P-inefficient cultivars, Lady Claire, Sieglinde, and Verdi, could not produce tubers under P deprivation conditions, as well as the ability to efficiently uptake P under low-level conditions, but they were efficient in P uptake under high soil P conditions. Improved PUpE is important for plant tolerance with limited P availability, which results in the efficient use of the applied P. At the leaf level, increased accumulations of nitrate, sulfate, sucrose, and proline are necessary for a plant to acclimate to P deficiency-induced stress and to mobilize leaf inorganic phosphate to increase internal PUE and photosynthesis. The reduction in plant biomass and tuber yield under P-deficient conditions could be caused by reduced CO2 assimilation. Furthermore, P deficiency significantly reduced tuber yield, dry matter, and starch concentration in Agria, Milva, and Lilly. However, contents of tuber protein, sugars, and minerals, as well as antioxidant capacity, were enhanced under these conditions in these cultivars. These results highlight the important traits contributing to potato plant tolerance under P-deficient conditions and indicate an opportunity to improve the P efficiency and tuber quality of potatoes under deficient conditions using more efficient cultivars. Future research to evaluate molecular mechanisms related to P and sucrose translocation, and minimize tuber yield reduction under limited P availability conditions is necessary.

Expression of bacterial glutamine synthetase gene in Arabidopsis thaliana increases the plant biomass and level of nitrogen utilization

Biologia ◽  
2015 ◽  
Vol 70 (12) ◽  
Author(s):  
Chenguang Zhu ◽  
Guimin Zhang ◽  
Chunlei Shen ◽  
Shilin Chen ◽  
Yuanping Tang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Glutamine Synthetase ◽  
Biochemical Characterization ◽  
Plant Biomass ◽  
Amino Acid Content ◽  
Dry Weight ◽  
Total Amino Acid ◽  
Bacterial Strains ◽  
Plant Nitrogen ◽  
Protein Levels

AbstractChanges in expression of glutamine synthetase (GS) have effect on plant nitrogen metabolism. In order to improve nitrogen use efficiency, several attempts at over-expressing GS II genes in plants have been previously undertaken, however few GSI and III genes are found such application. In this study, two GS I genes were cloned from bacterial strains and were transformed into Arabidopsis thaliana. Expression of the genes was confirmed under both mRNA and protein levels. Phenotypic studies revealed that all transgenic Arabidopsis lines showed enhanced fresh weight (12%) and dry weight (13%) compared with the wild-type plants at two concentrations of nitrate supplies. Further biochemical characterization confirmed that the transgenic lines had higher total nitrogen content (increased by 5-8%), soluble protein concentration (increased by 7-11%), total amino acid content (increased by 4-8%), leaf GS activity (enhanced by 8-14%) and free NO

Rhizobial inoculant formulations and soil pH influence field pea nodulation and nitrogen fixation

2000 ◽  
Vol 80 (3) ◽  
pp. 395-400 ◽  
Author(s):  
W. A. Rice ◽  
G. W. Clayton ◽  
P. E. Olsen ◽  
N. Z. Lupwayi
Keyword(s):  
Nitrogen Content ◽  
Soil Ph ◽  
Crop Production ◽  
Plant Biomass ◽  
Acid Soil ◽  
Dry Weight ◽  
Field Pea ◽  
Total Biomass ◽  
Plant Nitrogen ◽  
Liquid Inoculant

Crop production systems that include field pea (Pisum sativum L.) in rotation are important for sustainable agriculture on acid soils in northwestern Canada. Greenhouse experiments were conducted to compare the ability of liquid inoculant applied to the seed, powdered peat inoculant applied to the seed, and granular inoculant applied in a band with the seed to establish effective nodulation on field pea grown at soil pH(H2O) 4.4, 5.4 and 6.6. Plants were grown to the flat pod stage, and then total plant biomass dry weight, dry weight of nodules, number of nodules, plant nitrogen content, and proportion of plant nitrogen derived from the atmosphere (%Ndfa) were measured. Granular and powdered peat inoculants produced greater nodule numbers and weight, plant nitrogen content, %Ndfa and total biomass than liquid inoculant in at least two of the three experiments. Only granular inoculant was effective in establishing nodules at soil pH 4.4, but granular and powdered peat inoculants were effective at pH 5.4, and all three formulations were effective at pH 6.6. The results showed that granular inoculant has potential for effective nodulation of field pea grown on acid soil. Key words: Rhizobium, inoculant formulations, field pea, nodulation, acid soil

scholarly journals Acidified Animal Manure Products Combined with a Nitrification Inhibitor Can Serve as a Starter Fertilizer for Maize

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1941
Author(s):  
Iria Regueiro ◽  
Peter Siebert ◽  
Jingna Liu ◽  
Dorette Müller-Stöver ◽  
Lars Stoumann Jensen
Keyword(s):  
Plant Biomass ◽  
Nitrification Inhibitor ◽  
Animal Manure ◽  
P Uptake ◽  
Land Application ◽  
Atmospheric Environment ◽  
Mineral Fertilizers ◽  
P Availability ◽  
Starter Fertilizer ◽  
Plant P Uptake

There is an urgent need for better management practices regarding livestock farm nutrient imbalances and for finding alternatives to the actual use of mineral fertilizers. Acidification of animal manure is a mitigation practice used to reduce ammonia emissions to the atmospheric environment during manure storage and land application. Acidification modifies manure physicochemical characteristics, among which soluble N and P significantly increase. The main objective of this study was to investigate if acidification and the addition of a nitrification inhibitor to manure and placement of the treated manure close to the seed can stimulate maize growth by enhancing nutrient availability, specially P and consequently plant P uptake, at early development stages without the use of mineral N and P as a starter fertilizer. Raw dairy slurry and solid fractions from dairy slurry and digestate from a biogas plant were acidified to pH 5.5 and applied with or without a nitrification inhibitor (DMPP, 3,4-dimethyl pyrazole phosphate) to maize in a pot experiment, where biomass productivity, nutrient uptake and soil P availability were examined. Acidification increased the water-extractable P fraction of all slurry and digestate organic residues (by 20–61% of total P) and consequently plant P uptake from solid fractions of both slurry and digestate compared to the untreated products (by 47–49%). However, higher plant biomass from acidification alone was only achieved for the slurry solid fraction, while the combination of acidification and DMPP also increased plant biomass in the digestate solids treatment (by 49%). We therefore conclude that the combination of acidification and a nitrification inhibitor can increase the starter fertilizer value of slurry and digestate products sufficiently to make them suitable as a maize starter fertilizer.

scholarly journals Role of Methylotrophy During Symbiosis Between Methylobacterium nodulans and Crotalaria podocarpa

2005 ◽  
Vol 18 (10) ◽  
pp. 1061-1068 ◽  
Author(s):  
Philippe Jourand ◽  
Adeline Renier ◽  
Sylvie Rapior ◽  
Sergio Miana de Faria ◽  
Yves Prin ◽  
...  
Keyword(s):  
Root Nodule ◽  
Wild Type Strain ◽  
Plant Biomass ◽  
Root Nodules ◽  
Methylotrophic Bacterium ◽  
Plant Nitrogen ◽  
Affected Plant ◽  
Whole Plant ◽  
Fixation Capacity

Some rare leguminous plants of the genus Crotalaria are specifically nodulated by the methylotrophic bacterium Methylobacterium nodulans. In this study, the expression and role of bacterial methylotrophy were investigated during symbiosis between M. nodulans, strain ORS 2060T, and its host legume, Crotalaria podocarpa. Using lacZ fusion to the mxaF gene, we showed that the methylotroph genes are expressed in the root nodules, suggesting methylotrophic activity during symbiosis. In addition, loss of the bacterial methylotrophic function significantly affected plant development. Indeed, inoculation of M. nodulans nonmethylotroph mutants in C. podocarpa decreased the total root nodule number per plant up to 60%, decreased the whole-plant nitrogen fixation capacity up to 42%, and reduced the total dry plant biomass up to 46% compared with the wild-type strain. In contrast, inoculation of the legume C. podocarpa with nonmethylotrophic mutants complemented with functional mxa genes restored the symbiotic wild phenotype. These results demonstrate the key role of methylotrophy during symbiosis between M. nodulans and C. podocarpa.

scholarly journals Development and evaluation of a new Canadian spring wheat sub-model for DNDC

2011 ◽  
Vol 91 (4) ◽  
pp. 503-520 ◽  
Author(s):  
R. Kröbel ◽  
W. Smith ◽  
B. Grant ◽  
R. Desjardins ◽  
C. Campbell ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Soil Carbon ◽  
Spring Wheat ◽  
Plant Biomass ◽  
Dndc Model ◽  
Plant Nitrogen ◽  
Annual Variations ◽  
Using Data ◽  
Biomass Plant ◽  
Better Than

Kröbel, R., Smith, W. N., Grant, B. B., Desjardins, R. L., Campbell, C. A., Tremblay, N., Li, C. S., Zentner, R. P. and McConkey, B. G. 2011. Development and evaluation of a new Canadian spring wheat sub-model for DNDC. Can. J. Soil Sci. 91: 503–520. In this paper, the ability of the DNDC model (version 93) to predict biomass production, grain yield and plant nitrogen content was assessed using data from experiments at Swift Current, Saskatchewan, and St-Blaise, Quebec, Canada. While predicting wheat grain yields reasonably well, the model overestimated the growth of above-ground plant biomass and nitrogen uptake during the first half of the growing season. A new spring wheat sub-model (DNDC-CSW) was introduced with a modified plant biomass growth curve, dynamic plant C/N ratios and modified plant biomass fractioning curves. DNDC-CSW performed considerably better in simulating plant biomass [modeling efficiency (EF): 0.75, average relative error (ARE): 6.0%] and plant nitrogen content (EF: 0.61, ARE: −2.7%) at Swift Current and St-Blaise (EF of 0.75 and ARE of 2.3%), compared with DNDC 93 (biomass SC: EF 0.49, ARE 17.1%, SB: EF 0.02 ARE 33.4%). In comparison with DNDC 93, DNDC-CSW better captured inter-annual variations in crop growth for a range of wheat rotations, increasing the EF from 0.32 to 0.52 for grain and from 0.35 to 0.39 for straw yields. DNDC-CSW also performed considerably better than DNDC 93 in estimating soil carbon changes at Swift Current. Hence, DNDC-CSW has the potential to improve the performance of DNDC 93 in simulating wheat biomass, plant nitrogen, yield and soil carbon at various Canadian sites.

Cross-site comparison of herbivore impact on nitrogen availability in grasslands: the role of plant nitrogen concentration

Oikos ◽  
2009 ◽  
Vol 118 (11) ◽  
pp. 1613-1622 ◽  
Author(s):  
E. S. Bakker ◽  
J. M. H. Knops ◽  
D. G Milchunas ◽  
M. E. Ritchie ◽  
H. Olff
Keyword(s):  
Nitrogen Availability ◽  
Nitrogen Concentration ◽  
Plant Nitrogen ◽  
Herbivore Impact ◽  
Cross Site

Differential colonization by bioprospected rhizobial bacteria associated with common bean in different cropping systems

2017 ◽  
Vol 63 (8) ◽  
pp. 682-689
Author(s):  
Josiele Polzin de Oliveira-Francesquini ◽  
Mariangela Hungria ◽  
Daiani Cristina Savi ◽  
Chirlei Glienke ◽  
Rodrigo Aluizio ◽  
...  
Keyword(s):  
Common Bean ◽  
Plant Biomass ◽  
Cropping Systems ◽  
Root Nodules ◽  
Housekeeping Genes ◽  
Rrna Gene ◽  
N Fixation ◽  
N Accumulation ◽  
Symbiotic Efficiency ◽  
Plant Nitrogen

In this study, we evaluated the diversity of rhizobia isolated from root nodules on common bean (Phaseolus vulgaris) derived from Andean and Mesoamerican centers and grown under field and greenhouse conditions. Genetic characterization of isolates was performed by sequencing analyses of the 16S rRNA gene and 2 housekeeping genes, recA and glnII, and by the amplification of nifH. Symbiotic efficiency was evaluated by examining nodulation, plant biomass production, and plant nitrogen (N) accumulation. The influence of the environment was observed in nodulation capacity, where Rhizobium miluonense was dominant under greenhouse conditions and the Rhizobium acidisoli group prevailed under field conditions. However, strain LGMB41 fit into a separate group from the type strain of R. acidisoli in terms of multilocus phylogeny, implying that it could belong to a new species. Rhizobium miluonense LGMB73 showed the best symbiotic efficiency performance, i.e., with the highest shoot-N content (77.7 mg/plant), superior to the commercial standard strain (56.9 mg/plant). Biodiversity- and bioprospecting-associated studies are important to better understand ecosystems and to develop more effective strategies to improve plant growth using a N-fixation process.

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