EURASIAN JOURNAL OF SOIL SCIENCE

157 – 162

Authors: Renata Wilma Vasconcelos, Vanessa dos Santos Gomes, Diego Rodrigues de Lucena, Orione Alvares da Silva, Anaonio Cicero Sousa, Alexandre Fonseca D'Andrea

Mangrove ecosystems are of great environmental significance, because of their fragility and role in feeding and breeding various animal species. In northeastern Brazil, the disorderly occupation of estuarine areas and the urban sprawl have led to a considerable loss of the original area occupied by mangroves. In the municipality of Cabedelo, State of Paraíba, there are about 4,900 ha of remnant mangrove areas in the estuarine complex of the Paraíba River. However, information about the attributes of mangrove soils at this location is quite scarce. The aim of this study was to quantify the soil organic matter and soil acidity in mangroves located in the estuary of the Paraíba River, State of Paraíba, Brazil, in order to increase the database of soil attributes in this region. The study area is in local influence of the Restinga de Cabedelo National Forest (Flona), an environmental conservation unit of the Chico Mendes Institute for Biodiversity Conservation. For the choice of sampling points, we considered an area that receives direct influence of the eviction of domestic and industrial effluents. The soil of the study area is an “Organossolo Háplico” in Brazilian Soil Classification (Histosol), and was sampled at four point sites: one upstream of the effluent discharge (P1), one in the watercourse receiving effluent water (P2), one downstream of the effluent discharge (P3) and another near Flona (P4), at 0-20 and 20-40 cm, in four replications in time (28/08/2012 in the morning and afternoon, and 21/01/2013 in the morning and afternoon). Potential acidity, pH and soil organic matter (SOM) were determined. No significant differences were detected in the potential acidity of the four collection sites, which ranged from 0.38 to 0.45 cmolc dm-3. Soil pH was greatest at point P4 (7.0) and lowest at point P1 (5.8). The SOM was highest at point P1 (86.4 %) and lowest at P2 (77.9 %). The attributes related to soil acidity were not sensitive to indicate differences in the environments we evaluated, and seem not to indicate the contamination of mangroves by discharge of sewage into water bodies that border these environments. The high organic matter content of soils in the mangrove may have helped avoid significant fluctuations in soil acidity, because of the large buffering capacity.

172 – 181

Authors: David Pinskiy, Anastasiya Maltseva, Berta Zolotareva

The influence of the composition and properties of the mineral matrix in soils on the humification of corn residues was studied. The substrate (silica sand, loam, silica sand + 10% bentonite, or silica sand + 30% kaolinite) was mixed with 10% corn residues (milled to 3–5 mm) and incubated under stationary conditions for 6–19 months. Sampling for the analysis was performed every month, and a few times in the first month. The dynamics of mineralization and humification of plant residues was studied by applying elemental and bulk analyses of neogenic organic matter (OM), densitometric fractionation of substrates, FTIR spectroscopy, solid-phase 13C-NMR spectroscopy, and scanning electron microscopy with an electron microprobe. It was shown that the humification processes had a wavelike character for loam and sand substrates, which could be explained by the transformation of the microorganism populations together with the change in the amount and quality of OM in the system. The main mechanism for the stabilization of neogenic OM was adsorption on a mineral matrix with formation of relatively resistant compounds. This adsorption can be selective, depending on the composition and properties of the mineral matrix. The FTIR and 13C-NMR analyses of OM distribution in different substrates and densitometric fractions showed that sand and heavy fractions (HF >2.2 g/cm3) were enriched with compounds of an aromatic nature and polypeptides. Light fractions (LF-2, 1.4–2.2 g/cm3) accumulated compounds that also contained alkyl and carboxyl groups. The sandy substrate and HF have higher aromaticity indices than LF-2. Higher aromaticity index values of humus substances in the sandy substrate and HF in the loamy substrate, compared to LF-2, evidenced the formation of steady aromatic compounds, in which there may be kernels of humic acids (HA). We do not exclude the possibility of the matrix synthesis of the HA-like substances.

189 – 196

Authors: Guadalupe D. Calalang, Laurent Bock, Gilles Colinet

The study was conducted in the crop production areas of Miarayon Village, along the volcanic footslope of Mt. Kalatungan, Talakag, Bukidnon, Philippines. The elevation range of the longitudinal toposequence is 1,900 to 1,300 m asl. Production areas in the intermediate part of the toposequence (Salsalan) are located at about 1,600 to 1,400 m asl and in the lower part (Mambuaw) at 1,400 to 1,300 m asl. A total of 24 plots (12 in each location) which were planted to potatoes, carrots and corn were investigated. Soils are “Andic” Cambisol in open and convex positions and “Andic” Umbrisol in concave positions and toeslopes. The soil pH values ranged from 5.0-5.9. TOC and TN content were medium to high (4.1-8.9% and 0.30-0.80% respectively) with C/N ratios from 8-15. Range values of available Ca, Mg, K and Na were 1.9-11.24, 0.16-2.14 and 0.20-1.13, 0.04-0.13 cmol+kg-1, respectively. Top soil horizon exchangeable Al in Mambuaw was higher than in Salsalan. The differences in TN, C/N ratio and available K levels between the two locations were very highly significant, TOC was highly significant and for soil pH and available Ca and sum of bases, their disparities were significant. Available Mg and Na did not differ between the two sites. Mean potato yield in Salsalan was 8.97 tha-1 more than in Mambuaw. Mean carrot yield in Salsalan was 2.39 tha-1 lesser than in Mambuaw. Mean corn yield in Salsalan was higher than in Mambuaw by 0.29 tha-1 only. Correlations between potato yields with TOC, TN, and available Ca were highly significant while soil pH and K were significant. There was no relationship detected between potato yields and Mg and Na. There was no association detected between carrot yields with topsoil nutrient levels. Correlations were noted in corn yields with available Ca, Mg and K.

206 – 211

Authors: Jan Horak, Dusan Igaz, Elena Kondrlova

Tillage systems have impact on soil properties, crop growth and through this directly and indirectly influence the cropland CO2 emission and therefore the global warming. In Slovakia, the wider adoption of conservation practices has barriers such as large acreage of compacted soils, the absence of detailed regionalization of suitable soils for such practices and the scientific evaluation of its application on sustainable soil productivity and environment protection. This study evaluated the short-termeffect of conventional tillage (CT) and reduced tillage (RT) with (N1) and without (N0) N fertilizer application on soil CO2 emission from cropland planted with a red clover (Trifoliumpratense) during 40 days in 2013 on a tillage field experiment initiated in 1994. CO2 flux, soil temperature, and soil water contentwere monitored during the studied period in western Slovakia.Results of this study showed that there wasn’t significant difference (p< 0.05) in soil CO2 between conventional tillage and reduced tillage for both, not fertilized and fertilized plots. Averaged 40 days CO2 emissions were greater in reduced tillage as compared to conventional tillage for both fertilization levels. A linear regression between CO2 emission and soil temperature in conventionally and reduced tilled plots showed that soil temperature (r = 0.88-0.94; P <0.05) and not the soil moisture was a controlling factor. The highest CO2 emission were recorded on the CT and RT plots during the first two weeks after tillage, showing that the tillage resulted in a rapid physical release of CO2.

220 – 229

Authors: Liudmila N. Plekhanova

Studies on paleosols under an archaeological landmark of a rare type (a complex of kurgans with “whiskers”) dating from the Early Iron Age (the fourth century AD) have been performed in the steppe zone of the Transural Plateau. The size and shape of third-order soil polygons under stony ridges (“whiskers”) between the kurgans have been described in detail. The results have shown that the paleosol under the kurgans erected at the turn of the Late Sarmatian and Hun times (1600 years ago) is characterized by a higher humus content and deeper location of the carbonate horizon, compared to the recent soil. This indicates that an increase in atmospheric humidity took place in the fourth century AD.