EURASIAN JOURNAL OF SOIL SCIENCE

94-109

Authors: Mulugeta Tufa, Asmare Melese, Wondwosen Tena

Information about effects of land use types on selected soil physical and chemical properties is essential in sustainable utilization of soil resources. Therefore, this study was conducted to evaluate effects of land use types on selected soil physical and chemical properties on Kuyu district, Ethiopia. Totally, 24 composite soil samples were collected from grass, cultivated, forest and grazing lands by two soil depths (0-20 cm and 20-40 cm) with three replications. The two way analysis of variance was used to test the mean differences of the soil physical and chemical properties. The highest mean values of sand and clay were recorded in cultivated and grasslands, respectively. The mean bulk density of the soils ranged from 1.10 and 1.37 g cm-3 and the mean total porosity ranged from 48.2 to 58.7%, which indicated the less soil compaction. The pH ranged from 7.68 to 8.00 while the mean values of OM ranged from 3.15 to 5.02%. However, the mean values of total N ranged from 0.18 to 0.26%. The mean value of available P ranged from 1.26 to 5.37 mg kg-1, which implies that high deficiency of available P in the study area. The exchangeable basic cations and CEC values were within high to very high ranges in all land use types. Conversion of land use types from one to another has adverse effects on soil properties, especially overgrazing and cultivation of deforested land. Therefore, the proper soil and water conservation practice are important in the study area to enhance soil fertility and crop productivity.

118-130

Authors: Alemu Lelago, Tadele Buraka

The objectives of this study were to classify the soils of Tembaro district, and to identify its potentials for crop production. Five pits representing a pedon each were opened and profile in each pit was described for its morphological, physical and chemical characteristics according to standard procedures. A total of 20 disturbed soil samples and 16 core ring samples were collected from five representative profiles. The samples were analyzed in the laboratory for texture, BD, FC, PWP, Soil pH, EC, OC, TN, av.P, av.K, exchangeable bases, free and active iron and CEC. The results showed that the proportions of soil separates varied among profile and depth however, soils were all in clay textural class. The BD varied from 1.02 in the surface profile 1 to 1.25 g.cm-3 in the profile 3. Soil pH ranged from 6.8 to 5.4 in the surface horizons of all profiles with further decrease with depth indicating that the soils in the watershed are slightly acidic to moderately acidic. The OM and TN contents ranged from 2.90 to 5.43 and 0.23 to 0.45% in the surface horizon and they were in the low, low to medium and high categories respectively. The corresponding values for the remaining subsoil horizons were in the low categories. In all cases the contents of these parameters decreased considerably with depths. Available P was below critical values for all profiles and depths except for profiles 1 and 4. Exchangeable K was above critical value in all profiles with increasing trend along with depth of all profiles. Exchangeable Mg varied from 2.47 in surface horizon of profile 3 to 3.98 cmolc kg-1 in the surface horizons of profile 4 and increased with depth in all profiles except in profile 1. The observation with exchangeable K and Mg implies that there is leaching phenomenon in the study area. Ca ranged from 4. 35 cmolc kg -1 in profile 5 to 16.50 cmolc kg -1 in profile 1 with inconsistent trend with depth. The CEC from 18.22 cmolc kg -1 soil in surface horizon of profile 5 to 27.43 cmolc kg-1 soil in the surface horizons of profile 1 indicating they are in the medium to high ranges. But inconsistent trend in CEC distribution was observed with depth in all profiles. Based on the data collected from profile description study and soil physicochemical analytical data and according to FAO-WRD soil classification legend, the soil at Ambukuna watershed were classified as Haplic Nitisols (Endoeutric, humic), Haplic Nitisols (Hypereutric, humic), Haplic Nitisols (Endoeutric) and Haplic Nitisols (Epidystric, Humic). Most of the soil physical and some of the chemical characteristics studied could be ranked as good indicating that the area has high potential for agricultural production.

144-151

Authors: Md. Shahadat Hossain, GKM Mustafizur Rhman, Md. Saiful Alam, HA Mashuk, Md. Mizanur Rahman

Soil salinity expressed by electrical conductivity is a threat to crop production. The study aims were to establish relationships of electrical conductivity with its relevant soil properties, and analyze variability of soil salinity in the coastal zone of Bangladesh. A total of 150 geo-referenced saline soil samples from three coastal districts (Khulna, Satkhira and Bhola) of Bangladesh were analyzed for electrical conductivity of saturated paste extract (ECe), salt cations and other soil properties related to salinity. Statistical and geostatistical analyses were done as required. Moderate to strong significant regression relationships (R2=0.42 to 0.94) were found between ECe and salt cations (ECe=43.12*Na2-46.36*Na+13.97; ECe=12.26*K-2.5;ECe=1.16*Ca-1.97; ECe=0.32*Mg2-1.60*Mg+3.53) of the soils. On the contrary, weak relationships (R2=0.05 to 0.21) were found between ECe and other soil properties (ECe=4.41*organic carbon-0.56; ECe=-1.71*Txw (soil texture)+3.98;ECe=0.35*cation exchange capacity-1.98; ECe=0.06*specific surface area-0.55). Khulna soils (CV=65.99%) showed lower statistical variations while Satkhira (CV=97%) and Bhola (CV=105%) soils showed higher statistical variations for ECe. In contrast, Khulna, Satkhira and Bhola soils showed strong, moderate and weak spatial dependency for ECe, respectively. Interpolated spatial distribution maps of ECe showed variations in individual districts of study areas. The findings would assist soil scientists or farm managers to understand and/or manage saline soils, specially the soils of coastal zone of Bangladesh.

159-166

Authors: M. Amjad Qureshi, Haroon Shahzad, M. Sajjad Saeed, Sana Ullah, M. Asif Ali, Fakhar Mujeeb, M.A. Anjum

Legumes compensate mineral fertilizer by fixing nitrogen due to the specialized structures i.e. nodules by Rhizobium species. Literature revealed that legumes fixed nitrogen due to Rhizobium inoculation from 50-300 kg NPK ha-1 year-1. Rhizobium besides nitrogen fixation, solubilized phosphates, produced growth hormones and due to its root colonizing ability improved the growth and yield of non-legumes also and performed as plant growth promoting rhizobacteria (PGPR). Study was conducted to assess the relative efficiency of Rhizobium species for the growth and yield of cotton. Different isolates of five species of Rhizobium species responsible for different nodule formation in legumes were assessed for the auxin biosynthesis potential as IAA equivalents and isolates having higher values for IAA equivalents were used for experimentation. Results revealed that isolates of Rhizobium species improved the growth and physiological parameters of cotton. Higher values were root/shoot length and mass were observed with Rhizobium species of berseem (Br5). Bacterial inoculation with isolate (Br5) produced 60.94, 64.40 g shoot/root mass that is 16.70 and 23.80 % higher than control and percent increase improvements of cotton shoot/root length with Br5 i.e. 18.3, 24.8 % higher than that of control. Higher values of IAA equivalents were observed in root/shoot content of cotton with isolate of Br5. Bacterial inoculation improved the plant height, boll weight, number of bolls plant-1 and seed cotton yield with Br5 inoculation. The chlorophyll content, photosynthetic rate, transpiration rate and photo active radiation were also higher in the inoculated treatments. Results of present study clearly demonstrated that different isolates of Rhizobium species improved the growth and yield parameters of cotton and thus Rhizobium sp can be effectively utilized as bacterial inoculants in non-legumes.

176-183

Authors: Belgin Doğan, Coşkun Gülser

This study was carried out to determine the suitable classification of soil quality for vineyard fields of Akçaköy, Çatalca, Efemçukuru, Görece and Yeniköy villages in Menderes district of Izmir-Turkey. In vineyard fields, soil pH gave a positive relation with Ca and significant negative relations with P, Fe, Mn and Zn contents. Soil organic matter (OM) content had significant positive relations with EC, P, Fe, Mn and Zn and significant negative relations with bulk density and CaCO3 content. Soil quality index values for the vineyard fields varied between 0.38 and 0.85 with a mean of 0.57. Only one of the 28 soil samples taken from different vineyard fields was found in very suitable (S1:1.00-0.75) class, 8 in suitable (S2:0.75-060), 12 in marginal suitable (S3:0.60-0.50) and 7 in non-suitable (N:<0.50) class according to the soil quality index (SQI). Restricting soil factors for vine growth in the fields classified in S2 and S3 classes generally became low pH, low organic matter (OM), P, Fe, Mn, Cu, Mg and K contents than that of suggested levels. In addition to restring factors in S2 and S3 classes, physical properties in soils classified in N class were lower than suggested levels. The SQI values showed significant positive relations with grape yield, soil OM, P, K, Fe, Cu, Mn, Zn contents and significant negative relations with soil pH, exch. Ca and CaCO3 contents. The grape yields had also positive relations with soil OM, Fe, Mn, Zn contents and negative correlations with soil pH and CaCO3 content. Soil quality in a vineyard field should be assessed to reach successful sustainable and precision agricultural practices for high crop production.