Bermudagrass (Cynodon dactylon (L.) Pers.) is one of the primary perennial forages in the southeastern USA. Newer hybrid cultivars have superior production and nutritive value compared to common ecotypes. However, there are many challenges facing bermudagrass production in the region. First, the bermudagrass stem maggot (BSM; Atherigona reversura Villeneuve) has severely damaged bermudagrass throughout the region. Strategically timed pyrethroid applications significantly reduce adult BSM populations, but efforts are needed to develop integrated pest management plans. Second, an increasing number of producers are noting challenges with green-up following winter dormancy. This may be attributed to disease, unbalanced soil fertility, and weed pressure. Perhaps one of the most limiting factors for continued production is the deficit of sprigs and trained personnel to sprig hybrid bermudagrasses. This research is critically important as the need for cold-tolerant bermudagrass is increasing as tall fescue (Lolium arundinaceum (Schreb.) S. J. Darbyshire) is declining due to changes in temperature and precipitation throughout the northern parts of the region. Plant breeders are investigating hybrid bermudagrass at latitudes >35 degrees with respect to freeze or cold tolerance. Despite the many challenges facing hybrid bermudagrass in the southeastern USA, researchers are working to ensure its persistence, productivity, and availability for the future.

The main purpose of this article is to evaluate the influence of sand-gravel quarrying from the river bed on the bed deformation and the environment. Sand and gravel reserves are the second largest produced and traded resource after water. Every year, the demand for these materials in the world is 40-50 billion m3. Large-scale quarrying of sand and gravel from sea coasts and river beds leads to serious problems. Thus, the sand and gravel quarried from the sea shores cause flooding of the coastal zones, and the quarrying from the river beds leads to strong deformations. The sand resources produced from the seashores in Azerbaijan do not meet the current growing demand in the ever-expanding construction sector, and at the same time, they do not meet the quality standards. Therefore, the quarrying of sand and gravel from river beds has become an increasingly important process. Production of sand and gravel from river beds seriously impacts not only bed deformation but also the environment, flora, and fauna. The expansion of the river bed has led to the destruction of the forest areas, and the deepening has led to the depletion and disappearance of fish resources. Excavation works in the river bed also affect the infrastructure. Thus, the soil-cement road passing near the area where the excavation works were carried out, the bridge, and the electric columns have undergone influence. Therefore, as a result of the impact of anthropogenic factors in the Valvalachay River, the damage it caused to the environment was studied. Many parameters were measured in the Valvelachay River, and water consumption entering and leaving the holt was compared. For observation of changes along the river, a longitudinal profile in the study area was compiled based on the DEM (Digital Elevation Model) and topographic measurements in the ArcGIS program. Based on topographical and bathymetric measurements, it was determined that the depth in the part where the bed is deepened (the place where cobble gravel is mined) varies between 1.5-2 meters.

African mahogany (Khaya grandifoliola) is a tree species that has gained space in the forestry market, presenting utility in a wide range of uses, especially in Brazilian territory, where it is the main substitute for Brazilian mahogany wood. The objective of this work was to perform a path analysis between the response of nutrient solution to cadmium treatment and the other variables and attributes studied: amino acid, nitrate, protein, ammonium, reductase, IDM, cadmium. The experiment was carried out in a greenhouse. At first, seedlings were habituated to be later taken to the treatment, where the applicability was given by cadmium chloride monohydrate (CdCl 2.H2O) according to the nutrient solution. The experimental design was completely randomized (DIC), mixed in five concentrations (0; 10; 20; 30 and 40 mg L-1) with seven replications, totaling 35 experimental units. To perform the comparative examination, the data were exposed to the analysis of variance, followed by regression analysis. The path analysis allowed to directly verify that increasing doses of treatment with Cadmium (CAR) reflected in a negative correlation with the amino acid content (AAR) in the roots of mahogany plants. Abiotic stress, which was exposure to a toxic chemical (cadmium), decreased, in this case, the ability of plants to synthesize amino acids. Increasing doses of cadmium treatment (CAL) reflected in negative correlation with the protein content in the leaf (PRL) of mahogany plants. Evidently, the higher the cadmium concentration, the greater the damage to mahogany's metabolic systems. With this study, we showed that excess cadmium in the soil affects the development of seedlings of forest species such as mahogany.

This article attempts to predict the spatiotemporal changes of permafrost in the Headwater Area of the Yellow River (HAYR) on the northeastern Qinghai-Tibet Plateau, Southwest China by using field monitoring and numerical models. Permafrost in the HAYR is categorized into four types: low- and high-ice-content high-plain permafrost and low- and high-ice-content alpine permafrost. According to these permafrost types, changes in permafrost temperature were calculated by coupling a geometric model with the soil thermal conduction model. Based on the calculation results, this paper evaluates the changes of permafrost in the HAYR over the past 50 years and predicts the change trends of permafrost in the HAYR under the scenarios of RCP2.6, RCP6.0, and RCP8.5 for possible climate change in 2050 and 2010 from the Intergovernmental Panel on Climate Change Fifth Assessment Report. The results show that (a) in the process of permafrost degradation, the same permafrost type at different degradation stages results in different modes and rates of increasing temperature. The response of permafrost to climate change differs in various degradation stages of permafrost; (b) from 1972 to 2012, the areal extent of permafrost degradation was 1,056 km(2), resulting from a sharp air temperature increase after the 1980s. By 2050, the areal extent of permafrost degradation into seasonal frost is similar under the three scenarios of climate change. The areal extent of permafrost degradation is 2,224, 2,347, and 2,559 km(2) or 7.5%, 7.9%, and 8.6% of the total area in the HAYR, respectively. In RCP2.6, the areal extent of permafrost degradation into seasonal frost by 2100 would be approximately 3,500 km(2) greater than that by 2050. In RCP6.0, the areal extent of permafrost degradation by 2100 would be 10,000 km(2) or 32.9% of the total area in the HAYR. In RCP8.5, the area of permafrost degradation by 2100 would be 18,492 km(2) or 62.2% of the total area in the HAYR; (c) the active layer thickness (ALT) in the HAYR would increase significantly. The average of the ALT was 1.51 m by 1972 and 2.01 m by 2012, respectively. Under the RCP2.6, RCP6.0, and RCP8.5 scenarios, the basin-wide average of ALT would be 2.21, 2.40, and 3.08 m by 2050 and 2.78, 4.07, and 4.39 m by 2100, respectively.