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

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 NO−3 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

Effects of Slow Pyrolysis Biochar on CO2 Emissions from Two Soils under Anaerobic Conditions

The amendment of sandy Haplic Arenosol and clayey loam Gleyic Fluvisol with two rates of biochar derived from the slow pyrolysis of wood feedstock was evaluated under anaerobic conditions in a 63-day laboratory experiment. The rates of biochar were 15 and 30 t ha−1. Both rates of biochar were applied either with or without 90 kg ha−1 of nitrogen fertilizer (NH4NO3). Soils with no amendments were used as control treatments. Our results showed that only the incorporation of 15 t ha−1 of biochar, compared with the control treatment, led to a significant (p < 0.05) increase in volumetric water content of the sandy soil and a significant (p < 0.05) decrease in the parameters of the clayey loam soil. Increasing the biochar rate from 15 to 30 t ha−1 did not result in significant changes in volumetric water content in either type of soil. In the sandy soil, CO2 emissions were significantly (p < 0.05) higher in the treatments of 15 and 30 t ha−1 with N fertilizer compared with the control and N fertilizer treatment. In the clayey loam soil, the combined application of both rates of biochar with N fertilizer caused no significant increase in CO2 emissions compared with the control and N fertilizer treatment. The incorporation of 30 t ha−1 of biochar into the sandy soil contributed to a significant (p < 0.01) increase in the cumulative CO2 flux compared with the control treatment. Application of 15 and 30 t ha−1 of biochar into the clayey loam soil led, respectively, to a significant (p < 0.05) and a nonsignificant increase in the cumulative CO2 fluxes compared with the control treatment

Soil Organic-Matter in Water-Stable Aggregates Under Different Soil-Management Practices

An experiment of different management practices in a commercial vineyard, which was established in 2006 in the locality of Nitra-Dražovce, Slovakia on Rendzic Leptosol, was used to evaluate the dynamics of soil organic-matter parameters during the years 2008–2015. The following treatments were established: 1. G (grass without fertilisation as control), 2. T (tillage), 3. T+FYM (tillage + farmyard manure), 4. G+NPK3 (grass + 3rd intensity of fertilisation for vineyards: it means 125 kg/ha N, 50 kg/ha P, 185 kg/ha K), and 5. G+NPK1 (grass + 1st intensity of fertilisation for vineyards: it means 100 kg/ha N, 30 kg/ha P, 120 kg/ha K). The results showed that the soil-management practices in the vineyard significantly influenced the soil organic carbon in water-stable aggregates (SOC in WSA). The content of SOC in WSAma increased on average in the following order: T 5 mm, 5‒3 mm, 2–1 mm, 1–0.5 mm and 0.5–0.25 mm, respectively. The content of non-labile carbon reflected the contents of SOC in WSA. The highest labile carbon (CL) in WSAma, as compared to others, was found in T+FYM. Overall, application of higher NPK doses resulted in higher content of CL in WSAma compared with the lower applications of NPK. On the other hand, lower applications of NPK to soil increased the content of CL in WSAmi, as compared to G+NPK3

Can a single dose of biochar affect selected soil physical and chemical characteristics?

During the last decade, biochar has captured the attention of agriculturalists worldwide due to its positive effect on the environment. To verify the biochar effects on organic carbon content, soil sorption, and soil physical properties under the mild climate of Central Europe, we established a field experiment. This was carried out on a silty loam Haplic Luvisol at the Malanta experimental site of the Slovak Agricultural University in Nitra with five treatments: Control (biochar 0 t ha−1, nitrogen 0 kg ha−1); B10 (biochar 10 t ha−1, nitrogen 0 kg ha−1); B20 (biochar 20 t ha−1, nitrogen 0 kg ha−1); B10+N (biochar 10 t ha−1, nitrogen 160 kg ha−1) and B20+N (biochar 20 t ha−1, nitrogen 160 kg ha−1). Applied biochar increased total and available soil water content in all fertilized treatments. Based on the results from the spring soil sampling (porosity and water retention curves), we found a statistically significant increase in the soil water content for all fertilized treatments. Furthermore, biochar (with or without N fertilization) significantly decreased hydrolytic acidity and increased total organic carbon. After biochar amendment, the soil sorption complex became fully saturated mainly by the basic cations. Statistically significant linear relationships were observed between the porosity and (A) sum of base cations, (B) cation exchange capacity, (C) base saturation

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

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

The importance of initial application and reapplication of biochar in the context of soil structure improvement

It was shown that the use of biochar provides many benefits to agriculture by improving the whole complex of soil properties, including soil structure. However, the diverse range of biochar effects depends on its physicochemical properties, its application rates, soil initial properties etc. The impacts of biochar, mainly its reapplication to soils and its interaction with nitrogen in relation to water-stable aggregates (WSA) did not receive much attention to date. The aims of the study were: (1) to evaluate the effect of initial application (in spring 2014) and reapplication (in spring 2018) of different biochar rates (B0, B10 and B20 t ha−1) as well as application of biochar with N-fertilizer (40 to 240 kg N ha−1 depending on the requirement of the cultivated crop) on the content of WSA as one of the most important indicators of soil structure quality, (2) to assess the interrelationships between the contents of soil organic matter (SOM) and WSA. The study was conducted in 2017–2019 as part of the field experiment with biochar on Haplic Luvisol at the experimental station of SUA in Nitra, Slovakia. Results showed that initial application as well as reapplication of biochar improved soil structure. The most favorable changes in soil structure were found in N0B20B treatment (with biochar reapplication) at which a significantly higher content of water-stable macro-aggregates (WSAma) (+15%) as well as content of WSAma size fractions of > 5 mm, 5–3 mm, 3–2 mm and 2–1 mm (+72%, +65%, +57% and +64%, respectively) was observed compared to the control. An increase in SOM content, due to both, initial biochar application and its reapplication, significantly supported the stability of soil aggregates, while organic matter including humic substances composition did not

Combination of Biochar with N–Fertilizer Affects Properties of Soil and N₂O emissions in Maize Crop

One of the challenges of harnessing higher productivity levels and sustainability of agriculture related to N fertilization is in expanding soil N2O emissions, which has become a serious issue in recent years. Recent studies suggest that biochar may be the solution to this problem, but there is still a knowledge gap related to biochar application rates and its reapplication in Central Europe; therefore, in this study, we investigated the effect of biochar (initial application and reapplication in 2014 and 2018, respectively, at rates of 0, 10 and 20 t ha−1) combined with N-fertilizer (N0—0 kg N ha−1; N1—108 kg N ha−1 and N2—162 kg N ha−1) during the growing season of maize in 2019 (warm temperature with normal precipitation) on the changes of soil properties and N2O emissions in the silty loam, Haplic Luvisol, in the temperate climate of Slovakia. The results showed that the application and reapplication of biochar proved to be an excellent tool for increasing soil pH (in the range 7–13%), soil organic carbon—Corg (2–212%), and reducing the soil’s NH4+ (41–69%); however, there were more pronounced positive effects when biochar was combined with N-fertilizer at the higher level (N2). The same effects were found in the case of N2O emissions (reduction in the range 33–83%). Biochar applied without N-fertilizer and combined with the higher fertilizer level had a suppressive effect on N2O emissions. Biochar did not have any effect on maize yield in 2019

Response of soil organic carbon and water-stable aggregates to different biochar treatments including nitrogen fertilization

Recent studies show that biochar improves physical properties of soils and contributes to the carbon sequestration. In contrast to most other studies on biochar, the present study comprise a long-term field experiment with a special focus on the simultaneous impact of N-fertilizer to soil structure parameters and content of soil organic carbon (SOC) since SOC has been linked to improved aggregate stability. However, the question remains: how does the content of water-stable aggregates change with the content of organic matter? In this paper we investigate the effects of biochar alone and in a combination with N-fertilizer (i) on the content of water-stable macro- (WSAma) and micro-aggregates (WSAmi) as well as soil structure parameters; and (ii) on the contents of SOC and labile carbon (CL) in water-stable aggregates (WSA)