Measurements Of Biomass Production Research Articles

Molybdenum increases nitrogen use efficiency of sugarcane under limited N supply

The application of nitrogen (N) is a major challenge for sugarcane production due to the low nitrogen use efficiency (NUE). A possible key to increasing the NUE in sugarcane is the adequate supply of molybdenum (Mo) due to their role in nitrate reductase (NR) activity and N metabolism within plant tissue. We hypothesized that Mo supply increases NUE in sugarcane by improving NR activity and dry matter production. Our aim here was to test the combined application of N and Mo on sugarcane plantlets to evaluate the NR activity, biomass production, contents of N and Mo in leaves, and NUE. A growth-chamber experiment was run using N rates (Control; 30; 60; 120 and 240 mg kg−1) and Mo supply (Control and 0.5 mg kg−1) with four replications. Measurements of biomass production, NR activity, N and Mo content in leaves, SPAD index, and NUE were evaluated after 54 days of cultivation. Nitrogen rates increased biomass production, N-content in leaves, SPAD index and NR activity in the absence of Mo supply. Mo supply didn’t affect NR activity in leaves, but increased 48% the NUE at the lowest N rate (30 mg kg−1), suggesting a positive effect of Mo in another pathway of N metabolism. Our results suggest that the Mo application increases NUE under limited conditions of N supply by affecting other N-metabolism process rather than NR activity. Mo uptake increased with N doses, reaching maximum Mo-leaf contents of 17.5 mg kg−1 at the 151.2 mg kg−1 N rate. HIGHLIGHTS Nitrogen rates consistently increases biomass production and N nutrition of sugarcane plantlets Mo supply increases Mo-leaf content but does not affect NR activity Mo supply increases nitrogen use-efficiency under limited N supply.

Simplifying the protocol for the quantification of generalized soil fertility gradients in grassland community ecology

A new method, based on the latent variable measurement model, was recently developed to quantify generalised soil fertility (FG) in grassland ecosystems; i.e. the productive capacity of a soil at a multispecific scale when non-soil variables are held constant. To predict FG values, this method uses the relative growth rates (RGR) of Festuca rubra, Trifolium pratense, Triticum aestivum and Arabidopsis thaliana grown in intact soil. We investigated three simplifications of this method; namely, (i) the use of sieved soil instead of intact cores, (ii) the use of a single measure of biomass production instead of RGR and (iii), a combination of these two modifications. Using 26 grassland soils from southern Quebec (Canada), FG values were predicted for each method and compared using Pearson correlation coefficients. We also evaluated the performances of these different FG values, as well as measures of NO3−, P and K in predicting aerial net primary production (NPP) of the vegetation in these sites in a common non-soil environment. The four methods had comparable and very consistent FG values and, although they were not numerically equivalent, they were equivalent in predicting natural NPP of plant communities, and these predictions were better than the direct measures of NO3−, K and P flux rates as measured by Plant Root Simulator probes. Therefore, any of these methods could be used to assess the generalized fertility.

Development of an index-based insurance product: validation of a forage production index derived from medium spatial resolution fCover time series

An index-based insurance is being developed to estimate and monitor forage production in France in near real-time based on a forage production index (FPI) derived from the fraction of green vegetation cover (fCover) integral, obtained from medium spatial resolution time series. This article presents the first step of the scientific validation implemented. The grassland parcels, the field protocol established to collect biomass production data, and the method used to get the fCover are described. Local ground measurements of biomass production are compared with FPI values obtained from high-resolution space-based images. Discrepancies between the two variables are quantified by the coefficient of determination, the mean square error and the normalised root mean square error. First, fCover derived from the four sensors are coherent demonstrating the ability of the algorithm used to provide a consistent way of calculating fCover. Second, for the whole data set, the scatter plot between FPI and biomass shows an acceptable correlation (R2 = 0.75) improved when only taking into account data recorded up until the production maximum (R2 = 0.81). Third, the analysis carried out on the scale of the parcels, grass species, period of mowing or climatic conditions reveals variability on the regression coefficients indicating that other explanatory variables should be integrated to better compute the FPI.

Respuesta del pasto Bothriochloa saccharoides ([Sw.] Rydb.) a diferentes intensidades de sombra simulada en el valle cálido del Magdalena en el Tolima (Colombia).

Los sistemas silvopastoriles requieren de forrajes que soporten sombreamiento y buena calidad nutricional. El objetivo del estudio fue analizar indicadores agronómicos, producción de biomasa y calidad nutricional del pasto Vidal bajo simuladores de sombra, con porcentajes de 30%, 50% y 0% (control) de penumbra, este último actuando como control. el estudio se realizó en la Hacienda “La estrella”, ubicada en el municipio de Venadillo, Tolima. se realizaron mediciones de producción de biomasa a 52 días después de la siembra en dos épocas diferentes (húmeda y seca). se encontró una producción de materia seca en época húmeda de 3,47; 3,0 y 5,56 t ha-1 y en época seca de 2,33; 2,44 y 2,5 t ha-1 para coberturas de 50%, 30% y el control, respectivamente y no se encontraron diferencias significativas (P≤0,05) para esta variable entre las diferentes coberturas, lo cual sugiere un potencial del pasto para implementarse en sistemas agroforestales que presentan coberturas arbóreas moderadas. Con respecto a los indicadores agronómicos, la altura de la planta presentó diferencias significativas (P≤0,05) de los tratamientos 30% y 50% con respecto al tratamiento control, principalmente en la época seca. en términos nutricionales, los análisis de proteína en época húmeda fueron de 11,41%, 10,57% y 8,36% y en época seca de 9,61%, 10,51% y 12,95% para coberturas de 50%, 30% y control, respectivamente; el análisis de digestibilidad indica valores para la época húmeda de 70,02%; 71,92% y 67,77% y para época seca de 69,61%; 68,31% y 68,15% para coberturas de 50%, 30% y control, respectivamente. estos resultados demuestran un comportamiento productivo similar en las diferentes coberturas, lo cual lo hace un pasto tolerante a la sombra y una buena opción para la utilización en sistemas silvopastoriles.

Biomass production and assimilation of dissolved organic matter by SAR11 bacteria in the Northwest Atlantic Ocean.

Members of the SAR11 clade often dominate the composition of marine microbial communities, yet their contribution to biomass production and the flux of dissolved organic matter (DOM) is unclear. In addition, little is known about the specific components of the DOM pool utilized by SAR11 bacteria. To better understand the role of SAR11 bacteria in the flux of DOM, we examined the assimilation of leucine (a measure of biomass production), as well as free amino acids, protein, and glucose, by SAR11 bacteria in the Northwest Atlantic Ocean. We found that when SAR11 bacteria were >25% of total prokaryotes, they accounted for about 30 to 50% of leucine incorporation, suggesting that SAR11 bacteria were major contributors to bacterial biomass production and the DOM flux. Specific growth rates of SAR11 bacteria either equaled or exceeded growth rates for the total prokaryotic community. In addition, SAR11 bacteria were typically responsible for a greater portion of amino acid assimilation (34 to 61%) and glucose assimilation (45 to 57%) than of protein assimilation (< or = 34%). These data suggest that SAR11 bacteria do not utilize various components of the DOM pool equally and may be more important to the flux of low-molecular-weight monomers than to that of high-molecular-weight polymers.

Effects of spatial variability in light use efficiency on satellite-based NPP monitoring

Light use efficiency (LUE) algorithms are a potentially effective approach to monitoring global net primary production (NPP) using satellite-borne sensors such as the Moderate Resolution Imaging Spectroradiometer (MODIS). However, these algorithms are applied at relatively coarse spatial resolutions (≥1 km), which may subsume significant heterogeneity in vegetation LUE ( ϵ n, g MJ −1) and, hence, introduce error. To examine the effects of spatial heterogeneity on a LUE algorithm, imagery from the Advanced Very High Resolution Radiometer (AVHRR) at ≈1-km resolution was used to implement a LUE approach for NPP estimation over a 25-km 2 area of corn ( Zea mays L.) and soybean ( Glycine max Merr.) in central Illinois, USA. Results from several ϵ n formulations were compared with a NPP reference surface based on measured NPPs and a high spatial resolution land cover surface derived from Landsat ETM+. Determination of ϵ n based on measurements of biomass production and monitoring of absorbed photosynthetically active radiation (APAR) revealed that ϵ n of soybean was 68% of that for corn. When a LUE algorithm for estimating NPP was implemented in the study area using the assumption of homogeneous cropland and the ϵ n for corn, the estimate for total biomass production was 126% of that from the NPP reference surface. Because of counteracting errors, total biomass production using the soybean ϵ n was closer (86%) to that from the NPP reference surface. Retention of high spatial resolution land cover to assign ϵ n resulted in a total NPP very similar to the reference NPP because differences in leaf phenology between the crop types were small except early in the growing season. These results suggest several alternative approaches to accounting for land cover heterogeneity in ϵ n when implementing LUE algorithms at coarse resolution.

Performance of four ectomycorrhizal fungi on organic and inorganic nitrogen sources

The performance of isolates of the ectomycorrhizal fungi Coltricia perennis, Laccaria bicolor, Lactarius hepaticus and Paxillus involutus originating from Scots pine stands was studied on solid media with different concentrations of ammonium, glycine and glucose as inorganic nitrogen, organic nitrogen and carbon source. Laccaria bicolor was able to grow on both ammonium- and glycine-containing media. Biomass and growth rate of L. hepaticus and P. involutus on media with ammonium were generally higher than on media with glycine as nitrogen source. Coltricia perennis did not clearly show preference for either ammonium or glycine. Fractal dimensions, calculated from the biomass and radii of the fungi, were in the range 1–3. Fractal dimensions provided extra information about the foraging strategy of mycelia not obtained from growth rate and biomass production measurements, but cannot replace those because the use of fractal dimensions alone may lead to misinterpretation.

On the mass culture of microalgae: Areal density as an important factor for achieving maximal productivity

Scenedesmus obliquus was grown in a bioreactor under constant light and at a temperature of 24°C. From measurements of biomass production, it was possible to determine the influence of areal density on productivity in open as well as closed cultures. Maximal productivity occurred at an areal density of 40 to 45 g(dw) M −2, which was in good agreement with predicted values from a model. The optimal areal density for maximal productivity was influenced by factors such as culture depth, algal species, turbulence, available light, etc., and hence the establishment and maintenance of an optimal areal density is seen as one of the most important operational procedures for the mass culture of algae. Supersaturated concentrations of oxygen resulted in lower productivities due to photorespiration and/or oxidation.

Drought detection and quantification by reflectance and thermal responses

Drought can be detected by its effect on plant canopy development as indicated by measurements of biomass production, leaf area index (LAI), and ground cover in the reflective wavelengths (0.4–2.5 μm) and by canopy minus air temperature in the thermal infrared (8–14 μm) wavelengths. Both measures are quantitative, but quantification in terms of drought's economic impact requires that relationships between canopy ‘appearance’ as revealed by the measurements and effect on salable plant parts be established. The measurements themselves are becoming routine and their quantification in terms of drought's economic impact on grain sorghum and wheat grain yields have been demonstrated, but are not yet routine. Seven considerations in a system for drought quantification are discussed, and results of semi-operational applications to drought assessment that incorporate most of the seven considerations are described. Future drought assessment systems will likely combine physiologically based crop growth and yield models with soil characteristics, weather data, and Earth satellite spectral scanner observations.

Short Communication: Growth of seaweed Eucheuma cottonii in multi trophic sea farming systems at Gerupuk Bay, Central Lombok, Indonesia

Abstract. Sukiman, Faturrahman, Rohyani IS, Ahyadi H. 2014. Growth of seaweed Eucheuma cottonii in multi trophic sea farming systems at Gerupuk Bay, Central Lombok, Indonesia. Nusantara Bioscience 6: 82-85. Eucheuma cottonii is a seaweed commodity that has a high economic value because it contains compounds used as raw materials for industries. Various methods of seaweed farming have been developed, one of which is a system of cultivation Multi Trophic Sea Farming. This study aimed to analyze the growth of E. cottonii by observing the production of biomass in four trophic combinations in the system Multi Trophic Sea Farming. The study was conducted in the area of the marine aquaculture Gerupuk bay, Central Lombok, Indonesia. Experiments were performed on four plots cages with trophic combination treatment as follows: K1 (E. cottonii-lobster-abalone), K2 (E. cottonii-abalone-red carp), K3 (E. cottonii-abalone-grouper), and K4 (E. cottonii-abalone-pomfret fish). Seedling of E. cottonii weighing 50 g was tied to a rope and placed at a depth of 5 cm, 50 cm, 100 cm, and 150 cm. Measurement of biomass production was done every ten days until the thirtieth day. The highest biomass production of E. cottonii was obtained in K3 trophic combination (E. cottonii-abalone-grouper fish) with a depth of seedlings of 5 cm. The combination of K3 trophic is recommended for cultivation of seaweed in the MTSF system.