scholarly journals BIOLOGICAL ACTIVITY AND MINERALIZATION OF NITROGEN IN THREE SOILS AS INDUCED BY FREEZING AND DRYING

1963 ◽  
Vol 43 (2) ◽  
pp. 316-324 ◽  
Author(s):  
A. R. Mack

Rapid freezing and short-term drying effected marked changes in the biological activity of a Calcareous Black and a Brown Forest soil and only minor changes in a Solodized Solonetz soil which had a lower organic carbon and total nitrogen content. Freezing increased the initial rate of organic matter decomposition but further studies, with the Brown Forest soil only, showed that freezing did not affect the total amount decomposed over an extended incubation period; drying, however, increased the total amount decomposed throughout the incubation period. Freezing all soils decreased the number of viable fungi, whereas drying had no marked effect on the number of either fungi or bacteria. Freezing markedly increased the mineralization of nitrogen in the two higher organic matter soils whereas short-time drying did not. The influence of freezing on mineralization was reflected by a greater uptake of nitrogen by millet in one of the soils.

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7451
Author(s):  
Barbara Breza-Boruta ◽  
Karol Kotwica ◽  
Justyna Bauza-Kaszewska

Properly selected tillage methods and management of the available organic matter resources are considered important measures to enable farming in accordance with the principles of sustainable agriculture. Depending on the depth and intensity of cultivation, tillage practices affect soil chemical composition, structure and biological activity. The three-year experiment was performed on the soil under spring wheat (cv. Tybalt) short-time cultivation. The influence of different tillage systems and stubble management on the soil’s chemical and biological parameters was analyzed. Organic carbon content (OC); content of biologically available phosphorus (Pa), potassium (Ka), and magnesium (Mg); content of total nitrogen (TN), mineral nitrogen forms: N-NO3 and N-NH4 were determined in various soil samples. Moreover, the total number of microorganisms (TNM), bacteria (B), actinobacteria (A), fungi (F); soil respiratory activity (SR); and pH in 1 M KCl (pH) were also investigated. The results show that organic matter amendment is of greater influence on soil characteristics than the tillage system applied. Manure application, as well as leaving the straw in the field, resulted in higher amounts of organic carbon and biologically available potassium. A significant increase in the number of soil microorganisms was also observed in soil samples from the experimental plots including this procedure.


2004 ◽  
Vol 34 (5) ◽  
pp. 1136-1149 ◽  
Author(s):  
Jeffrey P Battigelli ◽  
John R Spence ◽  
David W Langor ◽  
Shannon M Berch

This study examines the short-term impact of forest soil compaction and organic matter removal on soil mesofauna, in general, and oribatid mite species, in particular. Both soil compaction and organic matter removal reduced the density of soil mesofauna. Stem-only harvesting reduced total mesofauna densities by 20% relative to uncut forest values. A combination of whole-tree harvest and forest floor removal with heavy soil compaction significantly reduced total soil mesofauna densities by 93% relative to the uncut forest control. Removal of the forest floor represents a substantial loss of habitat for most soil mesofauna. The forest floor apparently buffered the mineral soil by limiting both the impact of soil compaction and fluctuations in soil temperature and moisture. The relative abundance of Prostigmata and Mesostigmata increased with treatment severity, whereas that of Oribatida decreased. Species richness of the oribatid mite fauna was reduced as the severity of treatments increased. The number of rare oribatid species (those representing <1% of the total oribatid mite sample) decreased by 40% or more relative to the uncut forest control. Evenness also decreased as treatment severity increased. Oppiella nova and Suctobelbella sp. near acutidens were the dominant oribatid species in both the forest floor and mineral soil, regardless of treatment. Soil compaction and organic matter removal significantly impacted the density and diversity of soil mesofauna and oribatid mite fauna in the short term at these study sites.


2020 ◽  
Vol 11 (3) ◽  
pp. 97-104
Author(s):  
O. A. Litvinova ◽  
◽  
D. V. Litvinov ◽  
S. E. Dehodiuk ◽  
O. V. Dmitrenko ◽  
...  

The article presents the results of research on the biological activity of gray forest soil depending on the systematic use of organic and mineral fertilizers. It is established that effective reproduction of humus in gray forest soil is provided by organo-mineral (12 t of manure together with N80P60K80 application per 1 ha of crop rotation area) and organic (24 t/ha of manure), respectively 36,5 t/ha, and 35,6 t/ha. The application of only mineral fertilizers in the norm of N80P60K80 per 1 ha of crop rotation area resulted in a decrease in humus reserves by 9 % relative to the initial level (32,4 t/ha). The highest degree of humification of organic matter provided the option of applying organic fertilizers (60 t/ha) both separately – 36,0% and compatible with mineral – (60 t/ha manure + N80P60K80) – 34 %. Prolonged use of organic and mineral fertilizers in crop rotation significantly increased the total number of microorganisms in the soil. The result was increased decomposition of organic matter and increased release of CO2 from the soil. The areas with the highest biological activity and CO2 intensity were characterized by areas where the soil was systematically enriched with fresh organic matter. The intensity of biological processes in the organo-mineral system increased by 67 % relative to the variant without fertilizers and by 30 % relative to the variant with only N80P60K80. The use of organic and mineral fertilizers in one system stimulated the process of decomposition of fiber – at the level of 78,5 %, which in percentage terms exceeded the value of the indicators obtained for a purely mineral fertilizer system.


Pedosphere ◽  
2019 ◽  
Vol 29 (6) ◽  
pp. 810-818 ◽  
Author(s):  
Lulu GAO ◽  
Xicun ZHU ◽  
Zhaoying HAN ◽  
Ling WANG ◽  
Gengxing ZHAO ◽  
...  

1993 ◽  
Vol 1 (3) ◽  
pp. 217-229
Author(s):  
Egbert K. Duursma ◽  
Michel P. R. M. Boisson

The atmospheric oxygen reserve is so huge that, in the short term of hundreds or thousands of years, only minor changes can be expected due to fossil fuel burning and deforestation. Each oxygen molecule passes through a living organism, on average, only once in 9000 years. As a consequence, the fastest regulating system must take of the order of hundreds of years. Nevertheless, it is possible that the actual oxygen level is not necessarily at the optimum level for life, but is just an accidental one in the course of the earth's history. Tropical forests are not the ‘lungs’ of the earth in terms of hundreds of years, but only on a much longer time scale, likewise for all other vegetation which produce humus and the long-term fossil carbon. The driving force is related to the slight differences caused by external factors between photosynthesis and respiration, with subsequent organic matter deposition or consumption for short time regulation of hundreds of years; while, for periods of millions of years, the regulation depends on changes of weathering or burial of fossil sedimentary organic matter.


2020 ◽  
Vol 35 (3) ◽  
Author(s):  
Tayyaba Gul Malik ◽  
Hina Nadeem ◽  
Eiman Ayesha ◽  
Rabail Alam

Objective: To study the effect of short-term use of oral contraceptive pills on intra-ocular pressures of women of childbearing age.   Methods: It was a comparative observational study, conducted at Arif memorial teaching hospital and Allied hospital Faisalabad for a period of six months. Hundred female subjects were divided into two groups of 50 each. Group A, included females, who had been taking oral contraceptive pills (OCP) for more than 6 months and less than 36 months. Group B, included 50 age-matched controls, who had never used OCP. Ophthalmic and systemic history was taken. Careful Slit lamp examination was performed and intraocular pressures (IOP) were measured using Goldman Applanation tonometer. Fundus examination was done to rule out any posterior segment disease. After collection of data, we analyzed and compared the intra ocular pressures between the two groups by using ANOVA in SPSS version 21.   Results: Average duration of using OCP was 14.9 months. There was no significant difference of Cup to Disc ratios between the two groups (p= 0.109). However, significant difference was noted between the IOP of OCP group and controls. (p=0.000). Conclusion: OCP significantly increase IOP even when used for short time period.


2002 ◽  
Vol 51 (4) ◽  
pp. 269-279 ◽  
Author(s):  
Shin-ichi YAMASAKI ◽  
Shoji HIRAI ◽  
Masataka NISHIKAWA ◽  
Yoshinori TAKATA ◽  
Akira TSURUTA ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ziyou Zhou ◽  
Can Wu ◽  
Zhen Hu ◽  
Yujuan Chai ◽  
Kai Chen ◽  
...  

AbstractIt has been known that short-time auditory stimulation can contribute to the improvement of the balancing ability of the human body. The present study aims to explore the effects of white Gaussian noise (WGN) of different intensities and frequencies on dynamic balance performance in healthy young adults. A total of 20 healthy young participants were asked to stand at a dynamic balance force platform, which swung along the x-axis with an amplitude of ± 4° and frequency of 1 Hz. Their center of pressure (COP) trajectories were recorded when they were stimulated by WGN of different intensities (block 1) and different frequencies (block 2). A traditional method and detrended fluctuation analysis (DFA) were used for data preprocessing. The authors found that only with 75–85 dB WGN, the COP parameters improved. WGN frequency did not affect the dynamic balance performance of all the participants. The DFA results indicated stimulation with 75 dB WGN enhanced the short-term index and reduced the crossover point. Stimulation with 500 Hz and 2500 Hz WGN significantly enhanced the short-term index. These results suggest that 75 dB WGN and 500 Hz and 2500 Hz WGN improved the participants’ dynamic balance performance. The results of this study indicate that a certain intensity of WGN is indispensable to achieve a remarkable improvement in dynamic balance. The DFA results suggest that WGN only affected the short-term persistence, indicating the potential of WGN being considered as an adjuvant therapy in low-speed rehabilitation training.


Sign in / Sign up

Export Citation Format

Share Document