scholarly journals Validation of Cryogenic Vacuum Extraction of Pore Water from Volcanic Soils for Isotopic Analysis

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2214
Author(s):  
Diego Rivera ◽  
Karen Gutierrez ◽  
Walter Valdivia-Cea ◽  
Mauricio Zambrano-Bigiarini ◽  
Alex Godoy-Faúndez ◽  
...  

Andean headwater catchments are key components of the hydrological cycle, given that they capture moisture, store water and release it for Chilean cities, industry, agriculture, and cities in Chile. However, knowledge about within-Andean catchment processes is far from clear. Most soils in the Andes derive from volcanic ash Andosols and Arenosols presenting high organic matter, high-water retention capacity and fine pores; and are very dry during summer. Despite their importance, there is little research on the hillslope hydrology of Andosols. Environmental isotopes such as Deuterium and 18-O are direct tracers for water and useful on analyzing water-soil interactions. This work explores, for the first time, the efficiency of cryogenic vacuum extraction to remove water from two contrasting soil types (Arenosols, Andosols) at five soil water retention energies (from −1500 to −33 kPa). Two experiments were carried out to analyse the impact of extraction time, and initial water content on the amount of extracted water, while a third experiment tested whether the cryogenic vacuum extraction changed the isotopic ratios after extraction. Minimum extraction times to recover over 90% of water initially in the soil samples were 40–50 min and varied with soil texture. Minimum volume for very dry soils were 0.2 mL (loamy sand) and 1 mL (loam). After extraction, the difference between the isotope standard and the isotopic values after extraction was acceptable. Thus, we recommend this procedure for soils derived from volcanic ashes.

Author(s):  
André Luís Teixeira Fernandes ◽  
Eusímio Felisbino Fraga Júnior ◽  
Márcio José de Santana ◽  
Reginaldo De Oliveira Silva ◽  
Marcelo Moreira Dias

Coffee irrigation has increased in the main Brazilian coffee regions. However, in recent years, with climate change, years with water deficits greater than 150 mm have been observed, affecting the vegetative and productive development of the crop and also the replenishment of surface and underground springs. One practice that increases soil water retention capacity is organic fertilization. This work evaluated different combinations of irrigation and organic fertilization on the yield and quality of coffee produced in the Minas Gerais cerrado region. The treatments were: T1: total irrigation; T2: no irrigation; T3: total irrigation + organic fertilization (chicken manure, 10 ton ha-1); T4: no irrigation + organic fertilization (chicken manure, 10 ton ha-1); T5: 50% irrigation + organic fertilization (chicken manure, 10 ton ha-1). After 7 harvests, it was concluded that the treatment that combined organic fertilization with application of half of the necessary irrigation presented the best yield, superior to the treatment with total irrigation and exclusively mineral nutrition.


2018 ◽  
Vol 119 ◽  
pp. 346-353 ◽  
Author(s):  
Kimmo Rasa ◽  
Jaakko Heikkinen ◽  
Markus Hannula ◽  
Kai Arstila ◽  
Sampo Kulju ◽  
...  

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Karol Fijałkowski ◽  
Rafał Rakoczy ◽  
Anna Żywicka ◽  
Radosław Drozd ◽  
Beata Zielińska ◽  
...  

The aim of the study was to assess the influence of rotating magnetic field (RMF) on the morphology, physicochemical properties, and the water holding capacity of bacterial cellulose (BC) synthetized by Gluconacetobacter xylinus. The cultures of G. xylinus were exposed to RMF of frequency that equals 50 Hz and magnetic induction 34 mT for 3, 5, and 7 days during cultivation at 28°C in the customized RMF exposure system. It was revealed that BC exposed for 3 days to RMF exhibited the highest water retention capacity as compared to the samples exposed for 5 and 7 days. The observation was confirmed for both the control and RMF exposed BC. It was proved that the BC exposed samples showed up to 26% higher water retention capacity as compared to the control samples. These samples also required the highest temperature to release the water molecules. Such findings agreed with the observation via SEM examination which revealed that the structure of BC synthesized for 7 days was more compacted than the sample exposed to RMF for 3 days. Furthermore, the analysis of 2D correlation of Fourier transform infrared spectra demonstrated the impact of RMF exposure on the dynamics of BC microfibers crystallinity formation.


2019 ◽  
Vol 52 (1) ◽  
pp. 43
Author(s):  
Omid Bahmani

<p><strong> </strong>Tillage is one of the most important practices that have a significant influence on the soil hydro-physical properties. In this study, the impact of the type and number of input variables with five different methods of the Retc model to predicting the moisture retention curve and soil water content in three surfaces tillage NT (No-tillage), CP (Chisel Plough) and MP (Moldboard Plough) and the impact of tillage systems on soil hydro-physical properties were evaluated. According to results, when the field capacity and wilting point moisture was added to input data in Retc to predict the moisture curve model parameters, the EF was increased in MP (0.977, 0.95) and CP (0.891, 0.86) treatments compare the NT (0.665, 0.608). The Mualem–Van Genuchten model can describe satisfactorily the simulation of soil physical properties. The S-index, which was also affected by tillage, was greater than 0.066 in all tillage treatments, indicating good soil physical quality. Results indicated that NT had the highest and lowest values of bulk density (1.55 Mgr.m<sup>-3</sup>) and total available water (TAW) (0.038 m.m<sup>-1</sup>), respectively, and the differences between NT and MP in total porosity was significant. Overall, in most soil layers, tillage practices affected the porosity and total available water in the order MP &gt; CP &gt; NT. Water retention curves indicated that the water retention capacity was greater in tilled than in no-tilled and saturated hydraulic conductivity values were greater in tilled treatments than in NT soil.</p>


2019 ◽  
pp. 1327-1334
Author(s):  
Evandro Ademir Deak ◽  
Thomas Newton Martin ◽  
Glauber Monçon Fipke ◽  
Jessica Deolinda Leivas Stecca ◽  
Luciane Almeri Tabaldi ◽  
...  

Soil temperature and humidity are the chief determinants for good nodule formation at the time of sowing and emergence. The aim of this study was to estimate the soil temperature and humidity range, at which the Bradyrhizobium spp., and Azospirillum brasilense may have the highest effect on root enhancement and development of nodulation in soybean. Two experiments were conducted, the first of which was done in the seed laboratory performing the treatments listed as non-inoculated; inoculation with Bradyrhizobium; root enhancers; inoculation with Bradyrhizobium + root enhancers; co-inoculation with Bradyrhizobium + Azospirillum brasilense; co-inoculation with Bradyrhizobium + Azospirillum brasilense + root enhancers, and assessed at temperatures of 15, 20, 25, 30 and 35ºC. The experimental design was completely randomized with distribution in a factorial. The second experiment was executed in a greenhouse, employing the same treatments affected in the seed laboratory experiment, but with the addition of non-inoculated control with mineral nitrogen. Tests were done at the soil moisture levels of 25, 50, 75 and 100% water retention capacity, forming a factorial 7 x 4 (only second experiment). All co-inoculated treatments induced the soybean root system to improve, in terms of length, volume, surface area and root diameter, exhibiting superiority to the uninoculated control in the 20 to 30ºC temperature range. The co-inoculation raised nodulation in the soybean crop, when soil water retention capacity was at the range of 56 - 96%, achieving higher means compared to the standard inoculation. The root planter added no improvement to either the root system or nodulation in soybean.


Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 350
Author(s):  
Shimaa M. Elsaeed ◽  
E. G. Zaki ◽  
Tarek M. Ibrahim ◽  
Nasser Ibrahim Talha ◽  
Hosam A. Saad ◽  
...  

The deficiency of water sources and the environmental disposal of large amounts of biomass waste (orange peels) produces economic and environmental problems, though its conversion into biochar by a pyrolysis procedure might be used to improve soil productivity. In the current study, we investigated the performance of superabsorbent biochar composite grafted on CMC as a low-cost, alternative, and biodegradable terpolymer composite (IPNCB) for soil water retention capacity. The IPNCB composite was synthesized by both microwave and conventional routes. The optimal reaction parameters proved that the microwave route has a high grafting percentage (%G) and short reaction time compared to the conventional route. The superabsorbent composite was characterized using different methods: FTIR, TGA, and SEM. The results show that the equilibrium water swelling (EW) of the IPNCB composite was improved at a 2% biochar concentration. The incorporation of biochar (BC) into the polymer network improved the water holding capacity (WHC) to 57.6% and water retention (WR) to 9.1% after 30 days. The degradation test indicates the IPNCB composite has a good degradability rate. Mixing soil with the prepared IPNCB composite can improve plant growth and reduce water consumption through the irrigation of arid lands. The IPNCB composite is a candidate in sustainable agriculture applications.


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