Dušan Igaz

Biochar and biochar with N-fertilizer affect soil N2O emission in Haplic Luvisol

Abstract The benefits of biochar application are well described in tropical soils, however there is a dearth of information on its effects in agricultural temperate soils. An interesting and little explored interaction may occur in an intensive agriculture setting; biochar addition may modify the effect of commonplace N-fertilization. We conducted a field experiment to study the effects of biochar application at the rate of 0, 10 and 20 t ha−1 (B0, B10 and B20) in combination with 0, 40 and 80 kg N ha−1 of N-fertilizer (N0, N40, N80). We followed nitrous oxide (N2O) emissions, analysed a series of soil physicochemical properties and measured barley yield in a Haplic Luvisol in Central Europe. Seasonal cumulative N2O emissions from B10N0 and B20N0 treatments decreased by 27 and 25% respectively, when compared to B0N0. Cumulative N2O emissions from N40 and N80 combined with B10 and B20 were also lower by 21, 19 and 25, 32%, respectively compared to controls B0N40 and B0N80. Average pH was significantly increased by biochar addition. Increased soil pH and reduces NO3−

How dose of biochar and biochar with nitrogen can improve the parameters of soil organic matter and soil structure

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The Effect of Different Rates of Biochar and Biochar in Combination with N Fertilizer on the Parameters of Soil Organic Matter and Soil Structure

content seen in biochar treatments could be the two possible mechanisms responsible for reduced N2O emissions. There was a statistically significant increase of soil water content in B20N0 treatment compared to B0N0 control, possibly as a result of larger surface area and the presence of microspores having altered pore size distribution and water-holding capacity of the soil. Application of biochar at the rate of 10 t ha−1 had a positive effect on spring barley grain yield.

Soil Particle Size Analysis by Laser Diffractometry: Result Comparison with Pipette Method

Abstract Biochar application to agricultural soils has a significant potential to influence soil resource availability and thus crop performance. A factorial experiment investigating effects of different biochar application rates combined with nitrogen fertilizer was conducted in field conditions on a Haplic Luvisol. The aim of this study was to evaluate the effects of biochar and biochar combined with fertilization on soil organic matter and soil structure parameters. The treatments comprised combinations of biochar application of 0, 10 and 20 t ha−1 (B0, B10 and B20) and 0, 40 and 80 kg N ha−1 of nitrogen fertilizer (N0, N40, N80) applied in a full-factorial design. Biochar application rate of 20 t ha−1 significantly increased soil organic carbon content (SOC) and non-labile carbon content (CNL), but decreased carbon lability (LC). The addition of biochar at 10 t ha−1 together with 40 and 80 kg N ha−1 significantly increased the values of SOC and CNL. On the other hand, B10N80 treatment resulted in a considerable decrease of carbon lability (LC). Overall, the lowest average content of water-stable micro-aggregates was found in the B20N80 treatment and then with B10N0 < B20N40 < B20N0 < B10N80 < B0N0 < B10N40. Biochar applied at 20 t ha−1 increased the critical level of soil organic matter and decreased the crusting index.

The Possibility of Using Digital Images in Assessment of Plant Canopy Development and Weed Spread

Since biochar is considered to be a significant source of carbon, in this work we have evaluated the changes in soil organic matter (SOM) and soil structure due to application of biochar and biochar with N fertilization, and have considered the interrelationships between the SOM parameters and the soil structure. The soil samples were collected from Haplic Luvisol at the locality of Dolná Malanta (Slovakia) during 2017. The field experiment included three rates of biochar application (B0 – no biochar, B10 – biochar at the rate of 10 t ha-1, B20 – biochar at the rate of 20 t ha-1) and three levels of N fertilization (N0 – no nitrogen, N160 – nitrogen at the rate of 160 kg ha-1, N240 – nitrogen at the rate of 240 kg ha-1). The rate of biochar at 20 t ha-1 caused an increase in the organic carbon (Corg) content. The combination of both rates of biochar with 160 and 240 kg N ha-1 also caused an increase in Corg. In the case of B20 the extractability of humic substances carbon (CHS) was 17.79% lower than at B0. A significant drop was also observed in the values of the extraction of humic acids carbon (CHA) and fulvic acids carbon (CFA) after the addition of biochar at a dose of 20 t ha-1 with 160 kg N ha-1. However, both rates of biochar had a significant effect at 240 kg N ha-1. After application of 20 t ha-1 of biochar the content of water-stable macro-aggregates (WSAma) significantly increased compared to control. This rate of biochar also increased the mean weight diameter (MWDW) and the index of water-stable aggregates (Sw) and decreased the coefficient of vulnerability (Kv). The biochar at a rate of 20 t ha-1 with 240 kg N ha-1 the value of MWDW increased and value of Kv decreased significantly. The contents of Corg and CL correlated positively with WSAma, MWDW and Sw and negatively with WSAmi and Kv. The extraction of CHA and CFA was in negative relationship with MWDW. We conclude that the application of biochar and biochar combined with N fertilizer had a positive influence on SOM and soil structure.

Biochar and biochar with N fertilizer as a potential tool for improving soil sorption of nutrients

Soil texture as the basic soil physical property provides a basic information on the soil grain size distribution as well as grain size fraction representation. Currently, there are several methods of particle dimension measurement available that are based on different physical principles. Pipette method based on the different sedimentation velocity of particles with different diameter is considered to be one of the standard methods of individual grain size fraction distribution determination. Following the technical advancement, optical methods such as laser diffraction can be also used nowadays for grain size distribution determination in the soil. According to the literature review of domestic as well as international sources related to this topic, it is obvious that the results obtained by laser diffractometry do not correspond with the results obtained by pipette method. The main aim of this paper was to analyse 132 samples of medium fine soil, taken from the Nitra River catchment in Slovakia, from depths of 15-20 cm and 40-45 cm, respectively, using laser analysers: ANALYSETTE 22 MicroTec plus (Fritsch GmbH) and Mastersizer 2000 (Malvern Instruments Ltd). The results obtained by laser diffractometry were compared with pipette method and the regression relationships using linear, exponential, power and polynomial trend were derived. Regressions with the three highest regression coefficients (R2) were further investigated. The fit with the highest tightness was observed for the polynomial regression. In view of the results obtained, we recommend using the estimate of the representation of the clay fraction (<0.01 mm) polynomial regression, to achieve a highest confidence value R2 at the depths of 15-20 cm 0.72 (Analysette 22 MicroTec plus) and 0.95 (Mastersizer 2000), from a depth of 40-45 cm 0.90 (Analysette 22 MicroTec plus) and 0.96 (Mastersizer 2000). Since the percentage representation of clayey particles (2nd fraction according to the methodology of Complex Soil Survey done in Slovakia) in soil is the determinant for soil type specification, we recommend using the derived relationships in soil science when the soil texture analysis is done according to laser diffractometry. The advantages of laser diffraction method comprise the short analysis time, usage of small sample amount, application for the various grain size fraction and soil type classification systems, and a wide range of determined fractions. Therefore, it is necessary to focus on this issue further to address the needs of soil science research and attempt to replace the standard pipette method with more progressive laser diffraction method.

Effect of biochar and nutrient amendment on vegetative growth of spring barley (Hordeum vulgare L. var. Malz)

Abstract Nowadays, there are various methods of plant biomass assessment available for the purposes of plant growth analysis. Visual plant coverage assessment is often subjective; the other methods are destructive or require purchasing some special devices. This paper presents the assessment of the possibilities and limitations of using digital images made by conventional digital cameras for the purposes of monitoring of the plant canopy development and weed distribution during a vegetation period using the example from the field experiment established on agricultural land in Malanta at the experimental site of the Slovak University of Agriculture. The study is focused on assessment of the effect of biochar application on gas emission, hydrophysical soil properties as well as plant response and yields and it was established in the spring of 2014. Downward images of corn (Zea mays L.) were taken during four sampling campaigns in the vegetation season 2015. Images were analysed by the BreedPix software that could estimate the portion of green fraction (count of green pixels) and thus the image-derived vegetation index (IDVI). According to the image analysis of photos taken during different sampling dates, it could be concluded that biochar addition had a positive effect on the plant growth (above ground biomass) since all treatments resulted in higher IDVIs at the end of the vegetative growth in comparison to control. Further, we assume that the increasing trend in the crop canopy growth was partially limited by competitive presence of weeds at the beginning of the study. According to our experience, we can recommend the software for temporal and spatial monitoring of agricultural crops development. The usage is limited to early growth stages. Moreover, it can be also used for assessment of the weed coverage.