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A talaj katabolikus aktivitás mintázatának elemzése mikrorespirációs (MicroResp™) módszerrel
Analysis of soil catabolic activity patterns by micro-respiration (MicroResp™)
Functional diversity of the soil microbial community participates in most of the soil ecosystem services, often they have an essential role. From the many theoretical and experimental approaches, the catabolic activity pattern based on MicroResp™ technique is shown here. The method is the extension of the old-fashioned substrate induced respiration method to the microplate based multi-substrate induced respiration detection, allowing in situ community level physiological pattern of the soil microbial community. As the substrate utilization of the individual microbes may differ, the substrate utilization pattern of the sample depends on the actual composition and abundance of the soil microbial community. Substrates used in this method can be variable, mainly simple sugars, amino acids, amines or carboxylic acids are applied. The microrespiration method is fast, sensitive and reliable, therefore it is recommended to use in planned experiments and in soil monitoring programs as well.
Talajnedvesség-tartalom mérése földradarral (GPR) és mezőgazdasági alkalmazhatóságának lehetőségei
Soil water content measurements with ground penetrating radar (GPR) and its application possibilities in the agriculture
Measurement of soil water content is complicated due to the soil heterogeneity and environmental variability. No single efficient method has been developed to map the different soil moisture zones at great depth at the field scale without disturbing the soil structure and paths of the waterflow.
Partially or completely non-destructive measurement of soil moisture is provided by ground-penetrating radar (GPR), which offers high resolution and significant penetration depth for medium-scale soil moisture measurements, bridging the methodological gap between small-scale point-based and large-scale remote sensing techniques. In addition, this technique can be used with better time efficiency compared to other destructive or non-destructive procedures.
GPR has been used for soil water content estimation including measuring soil water content profile, identifying specific soil water depths or soil water variation under irrigation conditions.
Despite the high potential of GPR for hydrological investigations, it is important to realize that no single geophysical method is able to perform optimally under all conditions. For example, GPR is mostly restricted to areas with relatively low electrical conductivity (low attenuation of the electromagnetic wave). In addition, some of the GPR interpretation methods require the presence of well identifiable and continuous GPR reflections, which requires sufficient and spatially continuous subsurface contrast in dielectric permittivity.
Soil moisture (considering its flow) is a key variable in the fields of agriculture. It is the essential requirement for plants to grow. Consequently, soil moisture is important for irrigation management particularly in semiarid and arid regions.
In this paper, the literature of the principles of GPR measurements and utilization possibilities is summarized with the emphasis on the agricultural sector. GPR can be a beneficial measuring device that can help in mapping soil moisture distribution, taking into account infiltration, but also water loss caused by evaporation and plant water absorption. Consequently, it can be used in agriculture, due to its precision at high central frequency values, even (fine)root characteristics of the plants, essentially the xylem-water relationship can also be determined (xylem transports water and water-soluble minerals and supply water used during photosynthesis). In addition, GPR can provide valuable information regarding natural stratification and soil compaction. The data interpretation of GPR measurements, in addition to soil compaction causing a decrease in the moisture of soils (as three-phase systems), can in principle be extended to other aspects of agrotechnology, such as soil contamination studying. However, it has not been sufficiently explored, as no recent literature can be found on this subject.
Soil radar can be a useful part of “Smart farming”, which can help in the selection of soil moisture measuring sensors placed in the soil as part of it. Especially when associated with the recently released new simultaneous multi-offset and multi-channel (SiMoc) GPR system, which enables fast soil profile mapping with seven receivers, but at the speed of a traditional single-channel GPR.
If complete non-destruction is the goal, air-coupled GPRs mounted on a drone can provide an opportunity. It should be noted, however, that due to the significant signal attenuation (wave scattering) occurring at the soil-air interface, only a small penetration depth can be achieved.
Az azbesztszálak kimutatására szolgáló vizsgálatok középpontjában a levegőszennyezettségi értékek álltak, de a 21. században felmerült az igény a problémakör kiterjesztésére. Az elmúlt években megjelent nemzetközi tudományos szakirodalmak megcáfolták az évtizedeken át fennálló feltételezést, miszerint az azbeszt csupán a levegőterheltség révén vált ki kockázatot. Vízminőségi és talajminőségi kutatások által teret nyert az azbesztszálak, különösen a krizotilszálak alternatív transzportútjainak vizsgálatát célzó kutatásterület. Annak ellenére, hogy mind a települési, mind pedig a mezőgazdasági vízgazdálkodás potenciálisan érintett a krizotil-azbeszt jelenléte kapcsán, nincs nemzetközi szinten egységes és elfogadott módszer vagy küszöbérték az egyes vízforrások biztonságára vonatkozóan. A kutatások nyilvánvaló korlátja, hogy csekély mennyiségű és minőségű tudás érhető el. Az azbesztszálak megjelenése az egyes vízbázisokban jelentősen megváltoztatja mind a mezőgazdasági, mind a települési vízgazdálkodás környezeti hatásoknak való kitettségéről alkotott eddigi ismereteinket. Az öntözővizzel és a gyűjtött csapadékkal kijuttatott azbesztszálak hatásainak palettája mára túlhaladta a humán- és állategészségügyi hatásokat, immár figyelmet kell fordítani a vegetációs hatásokra is. Annak érdekében, hogy nagyobb betekintést nyerjünk az azbeszttoxicitás növényekre gyakorolt hatásaiba, sokkal több tudományos eredményre van szükség.
Jelen összefoglaló tanulmányban bemutatjuk az azbeszt, különös tekintettel a krizotil azbeszt legfontosabb tulajdonságait, humán-, állat- és növényegészségügyi kockázatait. Rávilágítunk arra, hogy ismereteink rendkívül hiányosak, valamint felhívjuk a figyelmet a települési és mezőgazdasági vízgazdálkodás érintettségének egyes faktoraira, közvetlen és közvetett kockázati tényezőire, valamint arra, hogy ezek miként hatnak az élőlényekre, kiemelt tekintettel a növényekre.
Rambutan (Nephelium lappaceum) production is growing worldwide so the treatment and utilization of Rambutan by-products has become a concern of manufacturers. The objective of this study was to evaluate the potential application of rhizobacteria to decompose Rambutan peel for organic fertilizer production. After the rhizospheric soil samples were selectively proliferated and preadded on agar medium containing only Rambutan peel, the rhizobacterial colony isolates were screened based on their ability to grow on this agar medium and then to degrade cellulose in Rambutan peel. The LD7.3 isolate from the Rambutan rhizosphere showed the highest efficiency in degrading Rambutan peel with 5.6% degraded cellulose content and was identified by the MALDI-TOF technique as belonging to Klebsiella. Klebsiella sp. LD7.3 grew well and maintained the same degrading activity after three times of subculturing in liquid medium. Notably, the supplementation of grinded Rambutan fruit peel to the liquid medium had a positive effect on the growth and the degrading activity of Klebsiella sp. LD7.3. This was the primary report on the application of rhizobacteria to degrade Rambutan peel and the results showed that this was a potential approach to reuse this waste source.
The experiment was conducted within a framework of a two-factor long-term trial at the Research Institute for Fisheries, Aquaculture and Irrigation, in Szarvas, Hungary. This was a special field experiment, in which lysimeters have been installed in the middle of 32 m2 field plots. The main factor was the water supply with 4 levels: i1: non-irrigated control; i2: irrigated with one third of the optimal water supply; i3: irrigated with two thirds of the optimal water supply; i4: optimum irrigated plot, according to the requirement of sweet corn test plant. The amount of released irrigation water was 0, 54, 106 and 158 mm per year on average over 5 years. Within every water supply treatment there were 4 nutrient supply rates (N): N1, N2, N3, N4 = 100, 200, 300 and 400 kg ha−1 NPK fertiliser substance in ratio 2:1:1. The number of replications was 4, and the experiment was arranged in split-plot design. In the studied years, the amount of precipitation varied between 92 and 264 mm from sowing to harvesting.
The effect of fertiliser was less in the non-irrigated treatments compared to that of the irrigated ones, and the yield was increased only up to 200 kg ha−1 NPK treatment level. The NPK dose of 300 kg ha−1 proved to be optimal in the irrigated treatments in which the utilization of fertilizer doses increased parallel to the improving water supply. In addition, the ratio of first class products (cobs longer than 20 cm) increased to a greater extent than the yield as a result of irrigation and fertilization. Water requirement of sweet corn proved to be between 400–450 mm resulting in an average yield of 20–24 t ha−1, of which 18–20 t ha−1 came from marketable cobs. The amount of evapotranspiration fluctuated between 270–440 mm during the five years, depending on the quantity of water supply, but it changed to a lesser extent than the amount of the yield. Increasing the fertilizer dose practically did not affect ET in non-irrigated plants, but increased it by 20–30 mm in irrigated ones. The change was not significant.
The productivity of ET was only 30–45 kg ha−1 mm−1 in the non-irrigated treatment, while it was 50–55 kg ha−1 mm−1 in the irrigated treatments, with higher values at the higher fertiliser rates. The productivity of irrigation water exceeded far over the productivity of ET at adequate nutrient supply. The yield increase per 1 mm of irrigation water was on average 60 kg ha−1 mm−1, which was considerably higher than the productivity of ET of non-irrigated plants (39 kg ha−1 mm−1). There was a positive correlation between the yield and ET, and a negative correlation between the yield and specific water consumption. Irrigation and fertilization increased the average yield to a greater extent than evapotranspiration, so as the average yield increased, the ET per unit of yield decreased, i.e. the productivity of evapotranspirated water increased.
