EURASIAN JOURNAL OF SOIL SCIENCE

96-104

Authors: Rajeev Joshi , Hukum Singh , Ramesh Chhetri , Saroj Raj Poudel , Sandip Rijal

Assessment of soil organic carbon (SOC) pool is an essential pace for understanding the carbon sequestration potential (CSP) of the soil system as a mitigation strategy and also investigate that they act as a source or sink for the atmospheric CO2 subject to the level of saturation. Improved CSP has been recognized as one of the possible solutions for mitigating climate change. The CSP of soil system for the community forests (CFs) in Nepal is not well recognized. Therefore, a study was conducted in two community-managed forests viz Ganesh (degraded) and Ramnagar (non-degraded) CFs situated in the Kanchanpur district of Nepal to quantify the SOC and Bulk density (BD). For determining SOC, systematic sampling with a sampling intensity of 0.5% was used for collecting altogether 189 soil samples from both the CFs. In addition, the soil samples from varying depths (0-10, 10-20, and 20-30 cm) of each soil profile were collected from each sampling plot. The mean SOC observed upto 30 cm soil depth in Ganesh and Ramnagar CF was 42.55 ± 3.10 t ha-1 and 54.21 ± 3.59 t ha-1 respectively. While, maximum SOC was noticed at 0-10 cm whereas minimum at 20-30 cm in both the CFs. Moreover, SOC decreased and bulk density increased with increasing soil depth in both the CFs. SOC and BD was negatively correlated in both CFs. The total SOC pool exhibited a significant (p<0.05) difference between the two CFs. Hence, the outcome of study shows that the both CFs has enormous potential to sequester the atmospheric concentration of CO2 into soil. With this concern, the participation of local people in sustainable management of community forests enhance the soil quality and meets strategy to mitigate the climate change.

111-122

Authors: Olufemi Emmanuel AyanfeOluwa , Olugbenga Oluseyi AdeOluwa , Kolapo Olatunji Oluwasemire , Rasheed Olufemi Awodoyin

Accelerated compost (AC) biotechnology that reduces composting time to less than one month is gradually finding its way to farmers. This study therefore evaluated the fertilizer potential of a brand of commercial AC (OBD-plus) on a degraded Alfisol in Ibadan (derived savannah) and Ultisol in Ikenne (rain forest) of Nigeria, using maize as a test crop. The experiment was laid out in Randomized Complete Block Design with three replications. The treatments were AC at 0, 60, 90, 120, 150 and 180 kg N ha-1, mineral fertilizer (NPK 15-15-15) and conventional compost (CC), each at 60 kgN/ha. Data collected on biomass yield, maize grain yield (MGY, t ha-1) and post-cropping soil chemical properties were subjected to ANOVA at α0.05. The average highest MGY from Ibadan (3.90) and Ikenne (3.86) were obtained from AC (180 kg N/ha), but these were not significantly different from other AC rates and NPK. The least MGY was obtained from control (2.1 and 2.0) which was significantly less than the CC (3.16 and 2.90). The AC improved the post-cropping soil pH, N and K. The mean MGY obtained from the six levels of AC in Ibadan; 3.44 and 3.98 t ha-1 in 2013 and 2014 were not significantly different from Ikenne (3.41 and 3.84 t ha-1). However, maize in Ibadan gave significantly higher biomass yield (19.40 t ha-1) than that of Ikenne (17.74 t ha-1) in 2013, with similar trend in 2014. Accelerated compost at 60 kg N ha-1 improved maize grain yield and post cropping soil properties in Ibadan and Ikenne, Nigeria as much as conventional compost. The performance of the accelerated compost was not location dependent in terms of MGY, but resulted in higher biomass production in the derived savannah ecology.

132-141

Authors: Elizaveta Konstantinova , Tatiana Minkina , Dina Nevidomskaya , Saglara Mandzhieva , Tatiana Bauer , Marina Burachevskaya , Svetlana Sushkova

Large rivers and especially their deltaic parts and adjacent coastal zones are subjected to strong anthropogenic influence and are often considered as hotspots of environmental pollution. The Don River is one of the largest and most important rivers in the South of Russia. The Don River basin is a highly urbanized area with developed agriculture and industry which negatively affect water quality, aquatic ecosystems and soils. The main objectives of the proposed research were to determine the levels exchangeable form of PHEs in soils of various aquatic landscapes of the study area, as well as to reveal the relationships between the content of exchangeable PTEs and the physical–chemical properties of floodplain soils. The obtained results showed that soils of the Lower Don and Taganrog Bay coastal zone are rather contrast in terms of properties and metal contents, which indicates the variability of landscapes, natural and anthropogenic processes in the studied systems. High CV values for a number of metals such as Pb, Zn, Cd and Cr indirectly indicate strong anthropogenic influence on these environments. The group median values for extractable forms for most of the metals except for Cu and Ni were higher for urbanized areas. The results of PCA analysis showed that there are two association of metals in terms of geochemical behavior and sources. The first one included Cr-Zn-Pb-Cd, the elements of anthropogenic origin, the second Mn, Ni, and Cu, which are probably of mixed origin. The obtained results showed that the Lower Don and Taganrog Bay coastal zone is a diverse and complex system subjected to anthropogenic activities, which is pronounced in the enrichment of aquatic soils with a number of metals and higher proportions of exchangeable forms from different types of sources that likely can be of both local and whole basin scale.

150-160

Authors: Emmanuel Amoakwah , Mohammad A. Rahman , Kwabena A. Nketia , Rousseau Djouaka , Nataliia Oleksandrivna Didenko , Khandakar R. Islam

Deforestation for conventional farming has affected soil quality (SQ) worldwide. The goal of our study was to evaluate the impact of land use change, from forest to subsistence farming, on SQ in Benin. Composite soils from forest, horticultural, agricultural, fallow, and degraded lands were collected to analyze for chemical and physical properties. Using inductive additive approach and principal component analysis (PCA), generalized (SQIg) and minimum dataset SQ (SQIMDS) indices were calculated. Results showed that upon conversion of forest, total organic carbon (TOC) decreased by more than 2 folds in fallow and degraded soils. A similar impact was observed on total nitrogen (TN). Soil cation exchange capacity (CEC) and base saturation (BS) were significantly higher under horticulture than in degraded lands. In contrast, carbon protection capacity (CPC) was significantly higher by 12-41% in forest soils compared to the lowest in degraded soils. Among the land uses, aggregate stability index (ASI) was, by far, the lowest (3.2%) in degraded soils and highest (7.5%) in horticulture soils. Soils under fallow and degraded lands had SQIg decreased by 5 to 16%, when compared with forest, indicating a significant SQ degradation. In contrast, SQIg under horticulture increased by 5%, suggesting a similar or even an improvement in SQ comparable to the forest. The PCA-based SQIMDS significantly and positively accounted for 70% of the variability in SQIg with a non-significant biasness (6 ± 3.8% at p<0.12). The TOC and CPC contributed most (20.9% and 21.1%) followed by clay (14.1%) and Ca+2: (Mg+2 + K+1 + Na+) (13.7%), TOC (11%), and ASI (10.5%) compared to lowest by K+ (9.7%) to account for SQIMDS variability. Our results concluded that there was no significant difference between SQIg and SQIMDS, which justified our results to use SQIMDS detecting management-induced changes in SQ.

171-178

Authors: Kazem Hashemimajd , Shaghayegh Kochakpour , Naser Davatgar , Elham Sohrabi

One of the approaches for increasing of yield and reduction of rice production costs is precision agriculture. Complete and correct determination of nutrition status of paddy soils is necessary in precise agriculture. To compare fuzz y and Boolean methods and mapping of nutrition status of nitrogen and phosphorus, 370 compound samples were collected from 306 ha of paddy soils of Rice Research Institute in Rasht County from plots with the dimension of 50 × 100 m. Total nitrogen and available phosphorus contents were measured. Results showed that interpolation and mapping by fuzzy logic was more accurate and correct in comparison with Boolean method and had greater distinguishing power to indicate deficiency of nutrients. Evaluation of dependency of paddy soils using of fuzzy function and Boolean method, showed that the southwest of study area have nitrogen and phosphorus deficiency and the other parts have minor limitation for these elements.