scholarly journals Emission of nitrous oxide and carbon dioxide from semi-arid tropical soils in Chiapas México

2010 ◽  
Vol 34 (5) ◽  
pp. 1617-1628 ◽  
Author(s):  
Alejandro Ponce-Mendoza ◽  
Juan Manuel Ceballos-Ramírez ◽  
Federico Gutierrez-Micelli ◽  
Luc Dendooven

The semi-arid region of Chiapas is dominated by N2 -fixing shrubs, e.g., Acacia angustissima. Urea-fertilized soil samples under maize were collected from areas covered and uncovered by A. angustissima in different seasons and N2O and CO2 emissions were monitored. The objective of this study was to determine the effects of urea and of the rainy and dry season on gas emissions from semi-arid soil under laboratory conditions. Urea and soil use had no effect on CO2 production. Nitrons oxide emission from soil was three times higher in the dry than in the rainy season, while urea fertilization doubled emissions. Emissions were twice as high from soil sampled under A. angustissima canopy than from arable land, but 1.2 lower than from soil sampled outside the canopy, and five times higher from soil incubated at 40 % of the water-holding capacity (WHC) than at soil moisture content, but 15 times lower than from soil incubated at 100 WHC. It was found that the soil sampling time and water content had a significant effect on N2O emissions, while N fertilizer and sampling location were less influent.

Radiocarbon ◽  
2015 ◽  
Vol 57 (3) ◽  
pp. 397-406 ◽  
Author(s):  
I Carmi ◽  
D Yakir ◽  
Y Yechieli ◽  
J Kronfield ◽  
M Stiller

A study of water and carbon isotopes was conducted in a bare plot in the unsaturated zone of the Yatir Forest in the northern Negev of Israel. Sediment cores were collected in three different seasons. Measurements include profiles of mineralogy, moisture and its δ18O and tritium content, dissolved inorganic carbon (DIC) and its δ13C (‰) and Δ14C (‰) content, and δ13C (‰) and Δ14C (‰) in the solid sediment. The profiles of moisture and δ18O in the cores show clearly the effect of evaporation. The tritium profile indicates infiltration of water (0.11 m yr−1). The source of carbon in the DIC is CO2 released by biotic activity through roots of trees and of seasonal plants, which show seasonal variations, and by decay of organic debris. The δ13C (‰) profiles show clearly the chemical transition from dissolved CO2 (δ13C = −22‰) to bicarbonate (δ13C = −14‰). At greater depth (–11.3‰), the δ13C becomes similar to the δ13C in the aquifer below (–12.5‰). The effect of secondary processes is evident in the profile of Δ14C in the DIC. It shows a clear decrease with depth due to exchange with the sediment at a rate of 10‰ yr−1. Precipitation of carbon from the DIC on the sediment is 1.1 mg C Lsed−1 yr−1, negligible compared to the 28 g C in 1 Lsed. In the solid sediment, there is a gradient in Δ14Ccarb at the top meter. The net precipitation of 14C from the DIC on the sediment (0.25 to 1.1‰ yr−1), corrected for decay, cannot be observed in the deeper sediment. The presence of 14C in the top 1 m of the sediment is explained by two possible processes: accumulation of 14C-tagged dust (∼0.05 mm yr−1) and/or long-term cumulative precipitation from the DIC.


2019 ◽  
Vol 10 (3) ◽  
pp. 376-383
Author(s):  
Wagner César Farias ◽  
Francisco Mickael Medeiros Câmara ◽  
Eduardo Castro Pereira ◽  
José Maria Costa ◽  
Gustavo Alves Pereira ◽  
...  

The pruning allows fruit harvest in different periods, according to the grower decision, being economically viable. The harvest can be scheduled according to the agronomical traits and due to the market price. The experiment was conducted in the didactic orchard of the Federal University of the Semi-Arid Region (UFERSA), from April 2013 to December 2014, in the municipality of Mossoro-RN. It was carried out in a randomized block design, with treatments arranged in a split-plot, which were composed by pruning periods, conducted in April (2013), November (2013) and July (2014). The subplots consisted of pruning intensities (short, medium and long); with four repetitions, where the experimental unit consisted of two plants that was pruned with 8 marked branches. From pruning to harvest, the the following botanical characteristics were evaluated in the marked branches: number of emitted sprouts by branches pruned at the day 15th (NBE); number of established branches by branches pruned at the day 50th (NRE); number of productive branches (NRP); vegetative number (VRN) and the total number of fruits (NFT). The evaluated characteristics presented a significant effect. The long pruning resulted in a higher number of fruits for all evaluated seasons. The best months for pruning was November and July. The guava tree ‘Paluma’ cycle, from pruning to harvest can vary according to the period of pruning, with 132 days in July and 150 days in April. durando entre 132 em julho a 150 dias em abril.  


2021 ◽  
Vol 11 (1) ◽  
pp. 168
Author(s):  
Marcos Venicios Ribeiro Mendes ◽  
Simone Ferreira Diniz ◽  
Cleire Lima da Costa Falcão ◽  
José Falcão Sobrinho ◽  
Francisca Edineide Lima Barbosa

Agriculture, to be successful, needs soil to have a potential nutrient composition that is relevant to plants. Therefore, it is necessary to identify the conditions for farming through soil analysis. Thus, this manuscript makes it possible to analyze the fruitfulness of two samples of the reddish-yellow acrisol—one with vegetation and the other without it—from Serra da Meruoca, a humid area in the semi-arid region of Ceará. Concerning the material and method, the stages were literature review, researches on cartographic bases, fieldwork, and data collection and their analysis in the laboratory. The results show that the area of acrisol with vegetation favors the practice of agriculture, a fact observed because of carbon (C), which is indicative of soil with intense cultivation, as well as calcium (Ca), which appeared in a significant level, typical of arable land. In the second sample, the acrisol without vegetation, the parameters that impose restrictions on agriculture are the pH, which contains exchangeable aluminum, indicative of high acidity that leads to a leaching process. Also, the aluminum (Al) at a low level reflected the need for dolomitic quicklime, for the amendment of a deficient soil. Therefore, studies on its fruitfulness are essential for farmers to reap the rewards according to the results obtained and analyzed.


Author(s):  
Takoua Ben Hlel ◽  
Feten Belhadj ◽  
Fatih Gül ◽  
Muhammed Altun ◽  
Ayşe Şahin Yağlıoğlu ◽  
...  

Background:: Luffa cylindrica is a plant that is widely distributed in Africa and Asia and it can be grown in regions with tropical or subtropical climates. Few patents dealt with Loofah biological properties, including some functional foods formulated from its leaves. Objective:: This study aimed to structurally and functionally characterize the bioactive compounds of L. cylindrica leaves grown in two different environments. Methods:: The extracts of L. cylindrica leaves collected from two Tunisian locations: Essouasi (LE), a semi-arid region and Medenine (LM) an arid region, were investigated for their phenolic compounds and fatty acids using HPLC/TOF-MS and GCMS techniques respectively. Furthermore, the antioxidant capacity was evaluated with DPPH, Chelating effect, Hydroxyl radical and Superoxide anion scavenging activities while the anticancer activity against HeLa cell lines was assessed using xCELLigence real time cell analyzer and lactate dehydrogenase cytotoxicity assay. Results:: The antiproliferative capacity of both extracts was time and dose-dependent with LE presenting the lowest HeLa cell index (CI = 0.035 ± 0.018, 250 μg/ml). LE also showed the best cytotoxic capacity (56.49 ± 0.8%) and antioxidant potential (IC50 = 54.41 ± 1.12 μg/ml for DPPH and 12.12 ± 0.07 μg/ml for chelating effet). 14 phenolic compounds were detected in LE with ferulic acid being the major compound (5128.5 ± 4.09 μg Phenols/g) while LM had only 6 phenolics. GCMS analysis showed the presence of omega-3 fatty acids in LE. Conclusions:: Our findings suggest that L. cylindrica leaves, especially when collected from semi-arid regions, are promising for formulating nutraceuticals of interest.


2021 ◽  
Vol 24 ◽  
pp. e00367
Author(s):  
Patrick Filippi ◽  
Stephen R. Cattle ◽  
Matthew J. Pringle ◽  
Thomas F.A. Bishop

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 927
Author(s):  
Jamshad Hussain ◽  
Tasneem Khaliq ◽  
Muhammad Habib ur Rahman ◽  
Asmat Ullah ◽  
Ishfaq Ahmed ◽  
...  

Rising temperature from climate change is the most threatening factor worldwide for crop production. Sustainable wheat production is a challenge due to climate change and variability, which is ultimately a serious threat to food security in Pakistan. A series of field experiments were conducted during seasons 2013–2014 and 2014–2015 in the semi-arid (Faisalabad) and arid (Layyah) regions of Punjab-Pakistan. Three spring wheat genotypes were evaluated under eleven sowing dates from 16 October to 16 March, with an interval of 14–16 days in the two regions. Data for the model calibration and evaluation were collected from field experiments following the standard procedures and protocols. The grain yield under future climate scenarios was simulated by using a well-calibrated CERES-wheat model included in DSSAT v4.7. Future (2051–2100) and baseline (1980–2015) climatic data were simulated using 29 global circulation models (GCMs) under representative concentration pathway (RCP) 8.5. These GCMs were distributed among five quadrants of climatic conditions (Hot/Wet, Hot/Dry, Cool/Dry, Cool/Wet, and Middle) by a stretched distribution approach based on temperature and rainfall change. A maximum of ten GCMs predicted the chances of Middle climatic conditions during the second half of the century (2051–2100). The average temperature during the wheat season in a semi-arid region and arid region would increase by 3.52 °C and 3.84 °C, respectively, under Middle climatic conditions using the RCP 8.5 scenario during the second half-century. The simulated grain yield was reduced by 23.5% in the semi-arid region and 35.45% in the arid region under Middle climatic conditions (scenario). Mean seasonal temperature (MST) of sowing dates ranged from 16 to 27.3 °C, while the mean temperature from the heading to maturity (MTHM) stage was varying between 12.9 to 30.4 °C. Coefficients of determination (R2) between wheat morphology parameters and temperature were highly significant, with a range of 0.84–0.96. Impacts of temperature on wheat sown on 15 March were found to be as severe as to exterminate the crop before heading. The spikes and spikelets were not formed under a mean seasonal temperature higher than 25.5 °C. In a nutshell, elevated temperature (3–4 °C) till the end-century can reduce grain yield by about 30% in semi-arid and arid regions of Pakistan. These findings are crucial for growers and especially for policymakers to decide on sustainable wheat production for food security in the region.


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