The impact of different fertilization methods on some microbiological soil characteristics119-126Views:91
In our experiment, we studied the impact of an organic fertilizer, Bactofil® A10 (half- and full dosage applied in field practice) and an artificial fertilizer of Ca(NO3)2 content in different dosages (20-40 mg kg-1) – in addition to control treatments – on two different soils (calcareous chernozem, humus sandy soil) in 2005-2006, the experiment was complemented with treatments applying 250% dosage (100 mg kg-1 N, Bactofil® A10 2.5 times the field dosage) and a compost from urban sewage (25 g kg-1 compost) was also tested on these two soil types. In the
experiment, several soil microbial parameters were studied. The experiment was set up at the Department of Agrochemistry and Soil Science using 1-kg pots.
Our laboratory experiments were performed at the soil microbiology laboratory of UD CAS Department of Agrochemistry and Soil Science, the total number of bacteria, microscopic fungi, nitrifying and aerob cellulose-decomposing bacteria were determined together with the CO2-production of soil, N content of the biomass and urease enzyme activity.
Statistical analysis of the data was done using the program SPSS 13.0, means of the measurements, deviation and significance values were calculated.
In 2005-2006, the effect of the different dosages of Bactofil® A10, and the Ca(NO3)2 fertilizer on the examined microbial parameters of calcareous chernozem and humus sandy soils can be summarized as follows:
• Concerning the total number of bacteria, both treatments were effective on calcareous chernozem soil, the higher (significant) increment in bacteria number was observed in the artificial fertilizer treatments, while in the humus sandy soil Bactofil treatments had a beneficial effect. The number of microscopic fungi also increased in both treatments, higher numbers were observed in the average of two years in the Bactofil treatments.
• The number of nitrifying bacteria was 2.5 times higher in both high-dosage treatments on calcareous chernozem soil, while on humus sandy soil a slight (not significant) increment was observed only int he high-dosage Bactofil treatment. The amount of aerob cellulose-decomposing bacteria significantly increased on calcareous chernozem soil in both the highdosage artificial fertilizer and the small-dosage Bactofil treatment, however, on humus sandy soil no significant increase was observed in either treatment.
• The CO2-production increased in both soil types, although it was not significant in either treatment. A higher (though not significant) soil respiration was observed in the Bactofil treatments in both soil types.
• The microbial biomass N values were significantly higher in the high-dosage Bactofil treatments, however, the high-dosage artificial fertilizer treatment also increased these values significantly on calcareous chernozem soil.
• On calcareous chernozem soil, urease activity was significantly increased and reduced by high-dosage artificial fertilizer treatments and Bactofil treatments, respectively. On humus sandy soil, urease activity was also reduced except for the high-dosage artificial fertilizer treatment. In 2007, the pot experiment with 250% dosages was complemented with the application of compost rich in organic matter, the results of these treatments are sumnmarized as follows:
• In the case of the total number of bacteria, all three treatments resulted in a significant increase on calcareous chernozem soil with the highest values in the Bactofil treatment. The Bactofil treatment was the most effective on the humus sandy soil, but the artificial fertilizer treatment also
resulted in a significant increment. In the case of the total number of fungi, Bactofil treatments resulted in the highest values on both soils, but the compost treatment also increased the number of fungi in calcareous chernozem significantly.
• The number of nitrifying bacteria was increased most (significantly) by the Bactofil and compost treatments on both soil types. The amount of cellulose-decomposing bacteria was significantly increased by he compost treatment on calcareous chernozem soil, while its effect was not significant on humus sandy soil. The number of these bacteria was increased significantly by the Bactofil treatment on humus sandy soil.
• On calcareous chernozem soil, all three treatments significantly increased CO2-production, while the compost treatments had the resulted in the largest increment in soil respiration on both soil types.
• The soil biomass N content was significantly increased in both soils by the compost treatment, while in the case of the humus sandy soil, the Bactofil treatment also resulted in a significant increment.
• Urease enzyme activity was significantly increased by the artificial fertilizer treatment on both soils. In calcareous chernozem soil, the Bactofil treatment resulted in a slight (not significant) reduction in enzyme activity. In humus sandy soil, the Bactoful treatment also resulted in a slight reduction, while the compost treatment increased (though not significantly) the urease activity.
Based on our results, it can be stated that all three treatments were effective with respect to the studied soil microbial parameters. For both the calcareous chernozem and the humus sandy soil, the organic fertilizer Bactofil and the compost with high organic matter content had a stronger effect on some soil microbial parameters than the artificial fertilizer.
Long-term effect of soil management on the carbon-dioxide emission of the soil515-527Views:78
CO2 emission from soils is one of the most important elements of the global carbon cycle, thus it has crucial rule in climate change. Each soil cultivation operation intervenes in the microbiological life of the soil, hence tillage is a factor through that the processes taking place in soil can be controlled. During the last decades, the organic material content of agricultural soils decreased to the half due to the intensive management resulting in the degradation of natural soil fertility. While intensive, plough-based tillage can cause soil degradation and erosion, the physical, chemical and biological status of the soil can be significantly improved through the application of conservation tillage methods. The results of long-term experiments prove that soil protective tillage enhances the enrichment of organic matter in the top layer of the soil. In order to reveal the role of tillage systems in CO2 emission from the soil, regular measurements were carried out in the plots with conventional and reduced tillage of the soil cultivation experiment of Research Institute of Karcag. Anagas CD 98 and Gas Alert Micro 5w infrared gas analysers were used to measure CO2-concentrations, and a specially developed method (consisting of a frame and a bowl) was applied to delimitate the measuring area. Most of the measurements were done on stubbles after harvest in order to exclude root respiration. The weather conditions of the examined 10 years were very changeable providing a good chance to compare them to each other. We found the tillage operations resulting in higher emission values in both tillage systems. On stubbles higher and more even emission was characteristic to reduced tillage due to the lower degree of soil disturbance and higher soil moisture content.
Changes of some soil chemical and microbiological characteristics in a long-term fertilization experiment in Hungary253-265Views:245
Agricultural management practices – directly or indirectly – influence soil properties.
Fertilization rates and crop rotation can strongly affect soil pH, soil nutrient supply and soil organic matter content due to the changes of microbial processes. The objective of this study was to compare the effects of different fertilization doses in monoculture and tri-culture of maize (monoculture: only maize grown since 1983, tri-culture: it is a three-year crop rotation system: pea – winter wheat – maize) on selected soil characteristics. The long-term fertilization experiments were set up in 1983 in Eastern Hungary. These experiments are situated west of Debrecen in Hajdúság loess region, on calcareous chernozem (according to WRB: Chernozems).
The test plant was maize (Zea mays L.). One-one pilot blocks were selected from monoculture and tri-culture of the long-term experiments. The observed soil samples were taken in the 30th year of the experiment, in 2013. The doses of NPK fertilizers increased parallel together, so the effects of N-, P- and K-fertilizers cannot be separated.
With the increasing fertilizer doses, the soil pH has decreased in both crop production systems and, in parallel, the hydrolytic acidity has significantly increased. A close negative correlation was proved between the pHH2O, pHKCl and hydrolytic acidity. An increased nutrient content in soil was recorded in every NPK treatment and the available phosphorus and nitrate content increased in higher proportion than that of potassium. Of the measured parameters of C-and N-cycles, fertilization has mostly had a positive effect on the microbial activity of soils. Besides the effects of fertilizer doses, correlation were looked for between soil microbiological properties. Evaluating the ratios among the measured parameters (organic carbon and microbial biomass carbon, OC/MBC ratio; carbon-dioxide and microbial biomass carbon; CO2/MBC proportion), the fertilization rate seems to be favoured by the increase of amounts of organic compounds
Study of the microbiological activity in the agrocenosis from Crisurilor Plain73-77Views:109
The seasonal variations of soil microorganisms depend on changes in the soil chemical properties and the microbiological processes of soil are determined in main by different cropping systems, soil management and season. Investigation of the microbiological properties of a haplic luvisol, under different cultivation conditions showed that anthropogenic factors such as fertilization and treatments with pesticides was favourable for certain microorganisms while others were inhibited by these factors. In order the quantitative occurence of microorganism was aerobic mesophilic heterotrophs (105–107 cellsxg-1 dry matter soil) were followed by Actinomycetes, yeast and mould (103–106 cellsxg-1 dry matter soil), nitrogen fixing bacteria (102–105 cellsxg-1 dry matter soil) and nitrifying bacteria (10-1–103 cellsxg-1 dry matter soil). The highest values of aerobic mesophilic heterotrophs were found in cropland and undisturbed meadow of haplic luvisol. Actinomycetes are more developed in undisturbed soils than in the cultivated soils. The number of yeast and mould was high in the apricot tree orchard, and Azotobacter and nitrifying bacteria were identified in a small number in all the soil variants studied. Among the total number of aerobic microorganisms, pH and humus content statistically proved relationship was established. Total number of yeast and mould depends on the proportion of 10.89% by moisture content and pH. The numerical presence of Azotobacter depends in a proportion of 9.6% by the ammonia nitrogen content and pH variations. The numerical presence of nitrifying bacteria depends in a proportion of 1.69% by the nitric nitrogen content and humus content variation.
Effects of cultivation methods on some soil biological parameters of a meadow chernozem soil (Vertisols)61-66Views:73
The effect of extended drought conditions on soil, the unfavourable cultivation technologies and the application of chemicals have been enhancing the processes of physical and biological soil degradation, so the fertility of soil is gradually declining.
The effects of two cultivation methods – traditional ploughing (TP) and conservation tillage (CT) – on the biological activity of a meadow
chernozem soil were examined in a long term experiment. Different parameters of the biological activity of soil were determined. These are
the numbers of total bacteria, microscopic fungi, aerobic cellulose decomposing bacteria, as well as the activities of some important soil
enzymes and CO2 production.
Conservation tillage seemed to be a more favourable cultivation method for the majority of microorganisms, the activities of urease and
dehydrogenase enzymes and CO2 production, compared to the traditional ploughing system. These parameters increased significantly,
especially in the upper layer of conservation tillage plots. Concerning the plant cultures, the majority of microbiological parameters were
higher in the soil of vetch (Vicia sativa L.) depending on the cultivation methods, so involving the pulses to the crop-rotation seems to be
very important in this soil type.
According to the ninth year’s results, the importance of conservation tillage as a means of protecting the soil biological activity in meadow
chernozem (Vertisols) can be established; it was proven by microbiological investigations.
Effects of some herbicides on the microbiological characteristics of soil nitrogen cycle under maize plantation93-100Views:70
Nitrogen is a key element for the living organisms and influence not only for the quantity but for the quality of the yield, considerable. Availability of nitrogen from the soil is influenced by several microbiological processes of the Nitrogen-cycle. Among the intensive agricultural production the herbicide application cannot be omitted more information needs therefore about the inhibitor effect of herbicides on the different microorganisms.
An experiment was set up on calcareous chernozem soil under maize culture. Effect of four different herbicides (Acenit, Frontier, Merlin, and Wing) was investigated. The effect of herbicides was measured to four microbiological parameters of the Nitrogencycle (abundance of nitrifying bacteria, nitrate solubilisation, biomass nitrogen and urease enzyme activity). There were singledouble- and five times of recommended doses of herbicides applied for two onsecutive vegetation periods.
From the results of the different doses of herbicides, the following can be stated:
– The Acenit has a stimulating effect on nitrifying bacteria in general. The Frontier and Merlin also influenced the quantity of nitrifyers, however in certain cases decreased in another cases increased the number of bacteria.
– The double doses and five times doses of herbicides was found to be increasing the nitrate content of soil, -especially in 2006.
– The quantity of microbial biomass nitrogen increased in the 60% of treatments and decreased in the 40% of the treatments.
– Except of the result of Wing in 2006 and Merlin in 2005, the effect of simple dose herbicides was the smallest on the urease enzyme activity. According to the results the effect of Merlin was positive; the effect of Wing was negative on the soil enzyme’s activity.
Regarding the application of four different herbicides in three different doses on the microbiological parameters of soil (at two consecutive years-) in 39% of the treatments has resulted a significant inhibitory effect, 28% of the treatments, however have significant stimulating effect on the parameters measured. More than 50% of the inhibitory effect was measured in case of the Wing, at more than 50% of the Frontier the microbiological parameters have not changed.
The impact of fertilisation on a few microbiological parameters of the carbon cycle45-50Views:154
The 30 years old long-term experiment of Látókép is continued in our experiments. The long-term fertilization experiment was set in 1983, and our sample was taken in spring 2014. The examinations of soil respiration processes and factors that influence soil respiration are required in optimal management. In our study, we interested to know how the growing levels of fertilization influence the microbial processes under nonirrigated and irrigated conditions in maize mono, bi, and triculture. The experimental results and those statistics suggest that the bi and triculture influenced higher microbial activity which was reflected in number of fungus, soil respiration, and microbial biomass carbon (MBC).
The effect of different herbicide on the number and activity of living microorganisms in soil76-82Views:119
Sustainable plant growth, considering the difficulties of weed elimination, cannot be effective without the application of herbicides. However, these chemicals have enormous ecological implications, including effects on the microbiological communities of soils. It is advisable to use herbicides that have minimal secondary effects on the environment and soil-living microorganisms. In contrast, herbicides with prolonged growth stimulating or inhibiting effects are not suitable, because both types have strong influences on the number and activity of bacteria, thus causing changes in the ecological equilibrium.
Preceding small plot experiments, laboratory tests were carried out to study the effect of herbicides used in maize cultures on the number of bacteria and growth of microscopic fungi.
Substances that were observed to have stronger influences were applied in small plot experiments set up in the experimental garden of the Department of Plant Protection of the University of Debrecen. We studied the effects of four herbicides (Acenit A88EC, Frontier 900 EC, Merlin SC and Wing EC) on the microbiological properties of the soil. These herbicides were used in different concentrations in maize culture, and we investigated the effects in different soil layers.
In the laboratory experiments, we determined the total number of bacteria and microscopic fungi and examined the growth of Aspergillus niger, Trichoderma sp. and Fusarium oxysporum on peptone-glucose agar containing herbicides.
During the small plot experiments, soil samples were collected 3 times a year from 2-20 cm depth. The total numbers of bacteria and microscopic fungi were determined by plate dilution method, while the method of most probable number (Pochon method) was used to determine the numbers of nitrifying bacteria and cellulose decomposing bacteria. To evaluate the microbiological activity of the soil samples we measured carbon-dioxide release (after 10 days incubation), nitrate production (after 14 days incubation) and the concentration of C and N in the biomass.
We can summarize our results as follows:
• In laboratory experiments, herbicides caused a decrease in the number of bacteria and inhibited the growth of microscopic fungi.
• Frontier 900 EC and Acenit A 880 EC had the strongest inhibiting effect on microorganisms.
• In small plot experiments, herbicide treatment decreased the total number of bacteria and microscopic fungi.
• Herbicides caused a significant increase in the number of nitrifying and cellulose decomposing bacteria.
• Different herbicides containing the same active compound had similar influences on soil microoorganisms.
• A significant increase was observed in the physiological processes of tolerant microorganisms surviving the effects of herbicides
Comparative analysis of certain soil microbiological characteristics of the carbon cycle137-141Views:126
In our researches, we examine the soil microbial parameters related to the carbon cycle. In this study, we compare the changes of microbial biomass carbon (MBC) and the soil CO2 production in soil samples which were taken in spring and autumn. The 30 years old long-term experiment of Debrecen-Látókép is continued in our experiments. The long-term fertilization experiment was set in 1983, and our sample was taken in spring 2014. The examinations of soil respiration processes and factors that influence soil respiration are required in optimal management. In our study, we interested to know how the growing levels of fertilization influence the soil respiration and microbial biomass carbon under non-irrigated and irrigated conditions in maize mono, bi, and triculture.
Examination the effects of different herbicides on the soil microorganisms of a calcareous chernozem121-126Views:71
Pesticides play a key role in fighting weeds, pests and parasitic fungi. According to surveys, pests reduce the yield of agricultural crops by 35% worldwide. Pests, fungi and weeds account for 14%, 12% and 9% yield loss, respectively (Gáborjányi et al., 1995). Chemicals have contributed to increasing and maintaining the yields of crop production for decades. Today, agricultural production (in spite of many efforts) is unthinkable without the use of pesticides (herbicides, insecticides and fungicides). On the other hand, these chemicals contribute to the pollution of the atmosphere, surface and underground waters, and agricultural soils, especially if they are applied improperly.
The sustainable agricultural production pays attention to environment-friendly cultivation-technologies; but at the same time it makes an effort to produce good quality and economical products. The examination of the herbicides’ secondary effects, fits into this chain of idas namely, how the herbicides affect – stimulating or inhibiting – the soil microbiological processes, prevention of soil fertility.
In the course of the experimental work the effect of herbicides on soil biological properties were examined in different maize (Zea mays) cultures. We wanted wished to know that how the herbicides affect the quantity change of soil microorganisms, the life of different physiological groups of bacteria and the activity of microorganisms. A small pot experiment was set up in 2008 with the application of two herbicides - Acenit A 880 EC and Merlin 480 SC – in the breeding house of the Department. The moisture content and nutrient supply were at optimal level in the experiment.
On the basis of results the following can be stated:
1. It can be stated that the two herbicides and all their doses affected negatively the number of total soil bacteria, the
inhibiting effects were significant. The quantity of microscopical fungi increased by the effect of Merlin 480 SC and decreased in the treatments of Acenit A 880 EC.
2. The Acenit A 880 EC had stimulating effect on the nitrate mobilization. The CO2-production was stimulated by the basic doses of herbicides; the other treatments did not influence the CO2-production significantly.
3. The quantity of microbial biomass-carbon –except for only one treatment- decreased significantly by the effect of herbicides. Besides it, the quantity of microbial biomass-nitrogen increased significantly in the treatments of Acenit A 880 EC.
4. The biomass of test plant decreased in the treatments of herbicides, their quantities were smaller than in the control. In the pots treated by Merlin 480 SC, parallel with the increase of doses decreased the quantity of plant-biomass.