scholarly journals Tillage and no-tillage effects on physical and chemical properties of an Argiaquoll soil under long-term crop rotation in Buenos Aires, Argentina

2020 ◽  
Vol 8 (2) ◽  
pp. 185-194 ◽  
Author(s):  
Ana Clara Sokolowski ◽  
Barbara Prack McCormick ◽  
Javier De Grazia ◽  
José E. Wolski ◽  
Hernán A. Rodríguez ◽  
...  
2012 ◽  
Vol 36 (4) ◽  
pp. 1299-1310 ◽  
Author(s):  
Carolina Tirloni ◽  
Antonio Carlos Tadeu Vitorino ◽  
Anderson Cristian Bergamin ◽  
Luiz Carlos Ferreira de Souza

Crop-livestock integration represents an interesting alternative of soil management, especially in regions where the maintenance of cover crops in no-tillage systems is difficult. The objective of this study was to evaluate soil physical and chemical properties, based on the hypothesis that a well-managed crop-livestock integration system improves the soil quality and stabilizes the system. The experiment was set up in a completely randomized design, with five replications. The treatments were arranged in a 6 x 4 factorial design, to assess five crop rotation systems in crop-livestock integration, and native forest as reference of soil undisturbed by agriculture, in four layers (0.0-0.05; 0.05-0.10; 0.10-0.15 and 0.15-0.20 m). The crop rotation systems in crop-livestock integration promoted changes in soil physical and chemical properties and the effects of the different systems were mainly detected in the surface layer. The crops in integrated crop-livestock systems allowed the maintenance of soil carbon at levels equal to those of the native forest, proving the efficiency of these systems in terms of soil conservation. The systems influenced the environmental stability positively; the soil quality indicator mineral-associated organic matter was best related to aggregate stability.


Author(s):  
Juliany Barbosa de Pinho ◽  
Aloisio Bianchini ◽  
Pedro Silvério Xavier Pereira ◽  
Letycia Cunha Nunes ◽  
Rodrigo Fernandes Daros ◽  
...  

From the pyrolysis process, biochar is a carbon rich and recalcitrant organic material with potential for long term carbon sequestration because of its aromatic structure. However, the physical and chemical properties of the biochar vary due to the diversity of raw material and the conditions of production. The present study aimed to evaluate the biochar from the sugarcane bagasse at different temperatures and under two conditions of pyrolysis. The biochar was produced at two final temperatures 200°C (1 hour); 250°C (1h) and 250°C (2h), with pyrolysis of an oxidizing and non-oxidizing atmosphere for both. PH, cation exchange capacity (CTC), carbon content (C), Nitrogen (N), hydrogen (H), H:C, C:N and ash ratios were evaluated. The contents of C, H, N and the atomic ratios H:C and C:N were higher in Biochar produced in a non-oxidizing atmosphere (BNO). However, the content of ash, pH and CTC were higher in Biochar produced in oxidizing atmospheres (BO). One can conclude the direct influence of the pyrolysis condition.


2017 ◽  
pp. 49-52
Author(s):  
S. S. Osuchuk ◽  
O. S. Yakovleva

Object: to study the physical and chemical properties of the lipoprotein complexes of rats` blood in the long-term administration of statins and vitamin D. Material and methods. The experiment was performed on 4 experimental groups of rats for 90 days: 1 - intact; 2 - placebo; 3 - intragastric administration of atorvastatin; 4 - intragastric administration of atorvastatin with α-calcidol. The lipoprotein blood complexes were isolated by the method of differential ultracentrifugation. The microflow and microviscosity of the lipoprotein complexes were determined using pyrene. Results. The placebo group revealed an increase of the micropolarity of the total lipid pool of VLDL and a decrease of the microviscosity of the annulary pool of LDL and HDL. The administration of atorvastatin reduces the microviscosity of HDL. The combined application of atorvastatin and α-calcidol reduces the microviscosity of HDL. Conclusion. We have drawn a conclusion about the complex effect of stress, atorvastatin, and α-calcidol on the physical and chemical properties of the lipoprotein blood complexes and a conclusion about the positive effect of atorvastatin and α-calcidol on the microviscosity of HDL.


2009 ◽  
Vol 1193 ◽  
Author(s):  
Karl R. Whittle ◽  
Mark G. Blackford ◽  
Gregory R. Lumpkin ◽  
Katherine L. Smith ◽  
Nestor J. Zaluze

AbstractRadiation damage and the effect on physical and chemical properties is an important component in the prediction of the long-term stability of waste form materials. As part of the ongoing goal of increasing the accuracy of long-term predictions of radiation damage, two types of material, based on proposed materials with a waste form application have been irradiated. Results have shown that Y2TiO5 (Y2.67Ti1.33O6.67), and Yb2TiO5 (Yb2.67Ti1.33O6.67), both of which are non-stoichiometric, disordered pyrochlore-based compounds, behave significantly different to the stoichiometric, ordered pyrochlore equivalent. For example the critical temperature, the temperature above which materials remain crystalline during irradiation, is found to decrease from the ordered equivalents, e.g. Y2Ti2O7. ⁡ A second material based on La2TiO5 has been found to behave differently to both La2/3TiO3 and La2Ti2O7, with a change in Tc of ∼ 200 K.


Revista CERES ◽  
2018 ◽  
Vol 65 (1) ◽  
pp. 35-43
Author(s):  
João Nacir Colombo ◽  
Mário Puiatti ◽  
Jaime Barros da Silva Filho ◽  
Ricardo Henrique Silva Santos ◽  
Luiz Antônio dos Santos Dias

ABSTRACT Intercropping using legumes is one of the ways to protect the main crop, and in long term improve the physical and chemical properties of the soil. The aim of this work was to evaluate the intercropping of Colocasia esculenta (L.) Schott (taro) and the tropical legume Crotalaria juncea L. (sunn hemp), cutting sunn hemp at ten periods during the cycle. The experiment was carried out under field conditions between 09/23/2010 and 06/04/2011. It consisted of 11 treatments related to the 10 cutting times of sunn hemp (55, 70, 85,100, 115, 130, 145, 160, 190, and 220 days after sowing - DAS) plus a control of taro with no sunn hemp. During the cycle, taro was evaluated for plant height and incidence of leaf burn. At the time of cutting the sunn hemp, the plant height, fresh and dry matter masses, and nutrient content of the biomass were calculated. During taro harvest, we evaluated the productivity of the mother rhizomes and classified the cormels. Taro plants shaded by sunn hemp showed a lower incidence of leaf burn. The sunn hemp cut from 145 DAS onwards affected the yield of comercial rhizomes and total and agroeconomic indexes. Sunn hemp cut up to 130 DAS provided better performance of taro, without compromising productivity and economic indicators, with the highest amounts of N and K observed in the biomass cut at 115 DAS.


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