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A talajok aggregátum-stabilitásának vizsgálati lehetőségei I. Makroaggregátum-stabilitás

Determination of soil aggregate stability I. Macro-aggregate stability

Agrokémia és Talajtan
Authors: Labancz Viktória, Barna Gyöngyi, Szegi Tamás, and Makó András

A makroaggregátumok stabilitásának meghatározására számos mérési módszer és értékelési lehetőség létezik. Ezek önállóan eredményesen alkalmazhatók az aggregátumok stabilitásának vizsgálatára (valamilyen romboló hatást megpróbálnak szimulálni, valamilyen körülményt megpróbálnak standardizálni stb.), ám ezek a módszerek egymással nehezen összevethetők. Az évek során jogosan merült fel a szabványosítás igénye, ám a kialakult nemzetközi szabvány módszertana igen bonyolult, éppen ezért csak kevesen kívánják azt alkalmazni. Hasonló a helyzet a különféle stabilitási mutatók esetében is: sokféle mutató használatos, ezek különkülön jól jellemezhetik a talajok aggregátum-stabilitását, de a mutatók párhuzamos használata több esetben eltérő stabilitási sorrendet eredményez a különféle talajoknál. Megfelelő megoldás lehetne, ha definiálni tudnánk, hogy mely módszer és mely mutató pontosan mit is fejez ki és mikor, milyen probléma vizsgálatakor, mely mutatót és mely módszert kívánatos alkalmazni. Kutatásainkat a továbbiakban ilyen irányban is folytatni kívánjuk.

There are several measurement and evaluation methods for determining the stability of macro-aggregates. These can be used effectively independently to test the stability of aggregates (attempting to simulate some destructive effect, attempting to standardise some condition, etc.), but they are difficult to compare to each other. Over the years, the need for standardization has rightly arisen, but the standard method developed is very complicated, which is why few people want to apply it.

Similarly, many different indicators are used, each of which can give a good characterisation of the aggregate stability of soils, but the parallel use of indicators often results in different stability rankings for different soils. An appropriate solution should be defined which method and which indicator expresses what exactly and when, and which indicator and which method should be used for which problem. We intend to continue our research in this direction.

In this manuscript we summarized the main macro-aggregate stability measurements and indices, reviewed the international and Hungarian scientific literature.

Open access

Land use change may modify key soil attributes, influencing the capacity of soil to maintain ecological functions. Understanding the effects of land use types (LUTs) on soil properties is, therefore, crucial for the sustainable utilization of soil resources. This study aims to investigate the impact of LUT on primary soil properties. Composite soil samples from eight sampling points per LUT (forest, grassland, and arable land) were taken from the top 25 cm of the soil in October 2019. The following soil physicochemical parameters were investigated according to standard protocols: soil organic matter (SOM), pH, soil moisture, NH4+–N, NO3–N, AL-K2O, AL-P2O5, CaCO3, E4/E6, cation exchange capacity (CEC), base saturation (BS), and exchangeable bases (Ca2+, Mg2+, K+, and Na+). Furthermore, soil microbial respiration (SMR) was determined based on basal respiration method. The results indicated that most of the investigated soil properties showed significant difference across LUTs, among which NO3–N, total N, and K2O were profoundly affected by LUT (p ≤ 0.001). On the other hand, CEC, soil moisture, and Na+ did not greatly change among the LUTs (p ≥ 0.05). Arable soils showed the lowest SOM content and available nitrogen but the highest content of P2O5 and CaCO3. SMR was considerably higher in grassland compared to arable land and forest, respectively. The study found a positive correlation between soil moisture (r = 0.67; p < 0.01), Mg2+ (r = 0.61; p < 0.01), and K2O (r = 0.58; p < 0.05) with SMR. Overall, the study highlighted that agricultural practices in the study area induced SOM and available nitrogen reduction. Grassland soils were more favorable for microbial activity.

Open access

Plant nutrition significantly influences yield and fruit quality in fruit orchards. In this three-year study (2016–2018), different fertilizer treatments were compared in an intensive sweet cherry orchard. Trees of cultivar ‘Carmen’ were grafted on Prunus mahaleb ‘Cema’ rootstock, and were trained to free spindle. For NP, NPK and NPKMg treatments, yield ranged between 11.8 and 16.6 kg/tree in the three years, while the yield was 9.1 kg/tree on the control trees. Crop load (fruit amount calculated to the trunk thickness) was 151–166 g cm-2 for fertilized trees, while it was 120 g cm-2 on the untreated trees. Fruit sizes of fertilized trees reached 30 mm in 2018, while the fruit sizes of control trees were smaller with 2.5 mm. Water-soluble dry matter content (%) of the fertilized trees was lower in 2016 and 2017, but higher in 2018 compared to the control plots. In 2017 and 2018, fertilizer treatments resulted in an increase of the content of phosphorus (16–70%), potassium (4–22%) and magnesium (12–43%) in the fruits compared to control plots.

Open access
Agrokémia és Talajtan
Authors: Kelemen Bettina, Füzy Anna, Cseresnyés Imre, Parádi István, Kovács Ramóna, Rajkai Kálmán, and Takács Tünde

The effects of cadmium (Cd) stress and arbuscular mycorrhizal fungus (AMF) inoculation were investigated in wheat [Triticum aestivum L. cv. TC-33] under controlled conditions. The experiments aimed to reveal what stress responses belong to the different levels of Cd load in the growth medium (0; 1; 2,5 and 5 mg Cd kg- 1 substrate). To detect the effect of Cd stress, we compared plant physiological and growth indicators measured with both in situ and destructive methods. Electrical capacitance (CR) was evaluated during the experiments as a method to indicate stress responses through of Cd-induced root system changes.

During the growth period, the photosynthetic activity (Fv/Fm), the chlorophyll content index (CCI) of the leaves, and the CR of the root-soil system were monitored in situ. After harvest, the membrane stability index (MSI), the cadmium and phosphorus concentrations of the plants, the root dry mass (RDM), the shoot dry mass (SDM) and the leaf area (LA) were measured. The root colonization of AM fungi was estimated by microscopic examination. Data matrices were evaluated with principal component analysis (PCA) which had been proved to be a good statistical method to the sensitivity between measurement methods.

Taking all parameters into account in the PCA, a complete separation was found between the contaminated and non-contaminated variants along the main component PC1. The measured values of the Cd1 treatment sometimes overlapped with that of control plants, but differed from that of the Cd2 and Cd3 doses. The parameters well reflected that AMF inoculation alleviated the stress caused by Cd. PCA shows a visible effect of AM, but the separation between mycorrhizal and non-mycorrhizal plants is weaker than that between Cd contaminated and non-treated ones. The Cd stress significantly decreased the Fv/Fm, CCI, CR, SDM, RDM and LA. The CR and growth parameters proved to be the best indicators to characterize the Cd phytotoxicity in the TC-33 wheat cultivar.

Open access