Irrigation effects on elephant grass morphology,and its genotype-dependent responses     

Robson Elpídio Pereira Ribeiro  Alexandre Carneiro Leão de Mello  Márcio Vieira da Cunha  Suellen Brandão de Miranda Costa  Janerson José Coelho  Rayanne Thalita de Almeida de Souza  Mércia Virginia Ferreira dos Santos 《Grass and Forage Science》2023,78(1):194-203

This study hypothesised that different elephant grass genotypes respond differently in terms of their morphological development to irrigation. The objective of this study was to evaluate how water availability could affect the morphological development of different genotypes of elephant grass. The treatments consisted of four genotypes of elephant grass [Cenchrus purpureus (Schumach.) Morrone], managed under irrigation or not, during a two-year field trial. The experiment was arranged in a randomised block design in a split-plot, with four replicates per treatment (n = 4). Between the genotypes, two of them were classified as tall-sized (IRI 381 and Elephant B), and two as dwarfs (Taiwan A-146 2.37 and Mott). A three-way interaction between season, irrigation, and genotype affected the variables plant height, stem diameter, number of dead tillers, light interception (LI), and leaf area index (LAI) (p < .05). The morphological development of all genotypes was negatively impacted by the dry season. All genotypes grew taller during the rainy season (p < .05) and had a greater light interception (62%–80%) compared to the dry period (28%–59%). The genotype Mott, showed comparable LI and LAI to the tall-sized genotypes, whilst Taiwan A-146 2.37 was characterized by the lowest values, despite being the genotype with the greatest tiller density (60 tillers m⁻²) (p < .05). The use of irrigation mitigated the negative effects of the dry season on the plants, however, the type and size (tall vs. dwarf) of the elephant grass genotypes defined the extent of the responses to the use of the irrigation during the dry period.  相似文献   

Soil mapping for precision agriculture using support vector machines combined with inverse distance weighting     

Pereira  Gustavo Willam  Valente  Domingos Sárvio Magalhães  de Queiroz  Daniel Marçal  Santos  Nerilson Terra  Fernandes-Filho  Elpídio Inácio 《Precision Agriculture》2022,23(4):1189-1204

Precision Agriculture - Kriging has been shown to be the best interpolator to interpolate maps in precision agriculture. However, Kriging requires a high number of sampling points to generate...  相似文献   

Use of geophysical methods for the study of sandy soils under Campinarana at the National Park of Viruá, Roraima state,Brazilian Amazonia     

Bruno Araujo Furtado de Mendonça  Elpídio Inácio Fernandes Filho  Carlos Ernesto Gonçalves Reynaud Schaefer  Anôr Fiorini de Carvalho  José Frutuoso do Vale Jr.  Guilherme Resende Corrêa 《Journal of Soils and Sediments》2014,14(3):525-537

Purpose

The vegetation of the Campinaranas occurs in humid areas with hydromorphic sandy soils at the Amazon region. Thus, the determination and in situ monitoring of moisture content in Campinarana soils, besides the detection of subsurface layers are key measures for studying these soil–vegetation systems. Also, the application of ground penetrating radar (GPR) in deep sandy sedimentary sequence of Amazonia is a promising tool to enhance the knowledge on depositional and soil formation features.

Materials and methods

We studied representative soils of the Campinaranas at the National Park of Viruá, state of Roraima (Brazilian Amazonia), through the use of geophysical methods (soil moisture sensors and GPR). The study was applied in four sandy soils. Besides chemical and physical analysis of soils, soil moisture sensors were installed for monitoring during an entire hydrological year (2010/2011), and performed the calibration of sensors , coupled with imaging of the soil along transects with GPR.

Results and discussion

As a result of calibration of the soil moisture sensors we obtained a general equation with an R ² greater than 0.9. There is an influence of soil moisture content and soil temperature in the distribution of vegetation types in Campinaranas. The use of GPR identified some determinants characteristics in these soils for the differentiating the Campinaranas, represented by spodic and C horizons.

Conclusions

The spodic horizons in soils under Forest Campinarana provided potential errors in the determination of soil moisture, requiring calibration data for the precise use of this device. The investigation of the soil through the GPR showed interesting results, which allowed continuous visualization of the main soil horizons along transects in the phytophysiognomies of Campinaranas.  相似文献   

Land use change drives the spatio-temporal variation of ecosystem services and their interactions along an altitudinal gradient in Brazil     

Gomes  Lucas Carvalho  Bianchi  Felix J. J. A.  Cardoso  Irene M.  Fernandes Filho  Elpídio I.  Schulte  Rogier P. O. 《Landscape Ecology》2020,35(7):1571-1586

Landscape Ecology - Land use and land cover (LULC) changes may affect the provision of ecosystem services. However, little is known how LULC changes influence the spatio-temporal variation in...  相似文献   

Determination of hormones inducing oocyte maturation in <Emphasis Type="Italic">Chalcalburnus tarichi</Emphasis> (Pallas, 1811)     

Unal G  Erdoğan E  Oğuz AR  Kaptaner B  Kankaya E  Elp M 《Fish physiology and biochemistry》2008,34(4):447-454

Chalcalburnus tarichi is an endemic cyprinid species living in the Lake Van basin, in eastern Anatolia, Turkey. The present study was undertaken to determine which hormones induce oocyte maturation in C. tarichi. The levels of 17α,20β,21-trihydroxyprogesterone (20β-S), progesterone (P), 17α-hydroxyprogesterone (17α-HOP), 11-deoxycortisol (11-DOC), and 17α-hydroxy-20β-dihydroprogesterone (17,20β-P) were measured in fish caught from Lake Van and the Karasu River, and injected with human chorionic hormone (hCG) (1,000 and 1,500 IU/kg). Oocytes of fish caught from the lake were also incubated in vitro with different doses (50, 200, and 1,000 ng/ml) of 20β-S, 17α-HOP, 11-DOC, and 17,20β-P. 11-DOC was found to be the most effective hormone among those measured for inducing oocyte maturation in vivo and in vitro. 17,20β-P could not be determined in the plasma of any fish in vivo (P < 0.05). 1,000 IU/kg dose of hCG given by injection caused a statistically significant increase in all plasma hormone levels (P < 0.05). It was found that there was a significant decrease in the P level only at 1,500 IU/kg dose of hCG injected (P < 0.05), while the level of other hormones increased at this dose (P < 0.05). It was also determined that all the hormones were effective in germinal vesicle breakdown (GVBD) in in vitro oocyte culture (P < 0.05). However, 11-DOC was found to be the most effective hormone in GVBD at a dose of 200 ng/ml (70% GVBD). In conclusion, 11-DOC synthesized during final oocyte maturation in C. tarichi was found to be a potent inducer of GVBD, which shows that 11-DOC may be described as an oocyte maturation steroid in this species.  相似文献