EURASIAN JOURNAL OF SOIL SCIENCE

189-195

Authors: Zhainagul Yertayeva, Rıdvan Kızılkaya, Sagynbay Kaldybayev, Nurzikhan Seitkali, Nurgul Abdraimova , Aigul Zhamangarayeva

Land use and amelioration practices are considered as main drivers in change of biological soil quality indicators in meadow Solonchaks. To gain insight into the impact of amelioration with alfalfa (Medicago sativa L.) cultivation on the underlying soil microbiological and biochemical properties, the objective of this study was to determine the effect of alfalfa (Medicago sativa L.) cultivation on biological soil quality indicators such as microorganisms counts, microbial biomass, basal soil respiration and enzyme activities (dehydrogenase, catalase, -glucosidase, protease, urease, alkaline phosphatase and arylsulphatase) in meadow Solonchak. Post-amelioration with alfalfa cultivation influenced the soil microbiological and biochemical properties and increased soil organic matter content and improved biological soil quality indicators. The results of this study may contribute to future researches for soil microbial communities in different type of amelioration practices in soil quality and sustainable productivity meadow Solonchaks.

208-220

Authors: Rania Aydi Ben Abdallah, Hayfa Jabnoun-Khiareddine , Ahlem Nefzi , Fakher Ayed , Mejda Daami-Remadi

Two endophytic bacteria, Bacillus subtilis SV41 (KR818071) and B. amyloliquefaciens subsp. plantarum SV65 (KR818073), were assessed under field conditions for their capacity to control tomato Fusarium wilt in tomato and their effects on soil microbial activity. Six months after planting, Fusarium wilt severity, estimated through the vascular browning extent in tomato stems, was significantly reduced by 82.3 and 88.2% compared to control following bacterial treatments. The frequency of F.oxysporum re-isolation from roots, collars and stems was also significantly lowered in treated plants compared to controls. These effects were associated with a significant improvement, by 10.6 to 16.3%over control, in plant height and root fresh weight and an increase in fruit production by 8.4-12.5%. As for microbial activity, F. oxysporum population in the rhizosphere of tomato plants treated with B. subtilis SV41 and B. amyloliquefaciens subsp. plantarum SV65 was reduced by 87.5-91.7%compared to the initial soil (sampled before planting) and by 88.4-92.3% relative to the rhizospheric soil of untreated plants (control soil). A significant enhancement in the total culturable bacterial community was also noted in the rhizosphere of tomato plants treated with both strains compared to initial and control soils where a significant enrichment in Pseudomonas and actinobacteria community was recorded.

229-236

Authors: Mohamed Said Awaad, Tarek H.M.A. Deshesh

Irrigation water is limiting factor for crop production in arid and semi-arid regions. Modern irrigation system such as drip irrigation are widely used in Egypt and also used in other countries especially have limited irrigation water resources. Drip irrigation provides the efficient use of limited water resources with increasing water productivity (WP). Application of nitrogen to wheat is needed to ensure the N availability throughout the growing season due to its important role in promoting both vegetative and reproductive growth. A field experiment was carried out during growing season of 2017/2018 at a private farm located at a newly reclaimed sandy soil at El-Sadat district El-Menofiya governorate , Egypt to study the effect of two nitrogen fertilizer types (ordinary and slow release N fertilizers) as urea 46.5%N and urea formaldehyde (38%N) with four application rates i.e., 0, 40, 60 and 100 kg N fed-1 (1 feddan=4200 m2) combined with drip irrigation moisture depletion from filed capacity (FC) (I1=100% of FC) and (I2=50% of FC) on wheat crop. The results showed that application of water depletion at (I1) through drip irrigation along with 100 kg N fed-1, from two sources of nitrogen recorded the highest yield of straw and grain and the nitrogen content as well as nitrogen use efficiency compared with the other rate and levels of nitrogen and irrigation, respectively. Also, water productivity increased with irrigation I1 FC and nitrogen levels and reached the highest values at 100 kg N fed-1 as fertigated urea compared with urea formaldehyde as slow release fertilizer.

249-256

Authors: Betül Bayraklı, Orhan Dengiz

Heavy metal contamination has caused serious environmental and health-related problems around the world. This research was conducted in arable lands of some basins located on Tokat province. The aim of this present study was to determine I-) some physico-chemical properties of soils, ii-) to find heavy metal (HM) content and their enrichment factor (EF) and iii-) to detect relationship between some physico-chemical properties and HM concentration. To identify the concentrations and sources of heavy metals, 280 soil samples (0-20 cm) were collected from the study area. Subsequently, in order to evaluate natural or anthropogenic sources of heavy metal content and their EF in agricultural fields, the concentrations of some HMs (Cd, Co, Cu, Cr, Ni, Pb and Zn) and some physico-chemical properties of soil samples were analyzed. The results showed that mostly the concentration of Ni followed by Cr exceeded their threshold levels. The local pollutions from Ni and Cr were attributed to the natural influences (particularly due to parent material). The concentrations of the other HMs are relatively lower than the critical values. The mean values of the HMs contents arranged in the following decreasing order: Ni>Cr>Cu>Zn>Co>Pb>Cd in the studied soil sample. In addition, it was found significantly positive relation between Pb and OM while the same relation was also found clay content and Cd and Pb. On the other hand, according to EF of HMs in total soil samples, Cd, Ni and Cr have found 16%, 10% and 6% soil samples as moderate enrichment class, whereas 55% and 1% of the total soil samples were determined significant enrichment class in terms of Cd and Ni elements. Besides, all other HM elements did not exceed minimal enrichment level. However, in some regions of the study area, the Cu, Cd and Pb contents were also slightly raised, this case possibly stems from anthropogenic effects such as excessive P fertilization, field traffic and pesticide using.

267-274

Authors: Abba Nabayi, Abubakar Halilu Girei , Mohammed Saleh Abubakar

The study was conducted to determine the effects of different tillage practices on some physical and hydraulic properties of soils in Hadejia Local Government Area of Jigawa state during the 2017 cropping season. The field experiment was laid in a Randomized Complete Block (RCB) Design in factorial arrangements with 4 treatments for tillage practices-TP (Zero tillage-ZT, Minimum tillage-MT, Conventional tillage-CT and Deep tillage-DT) and sampling depth-SD (5 cm, 15 cm, 25 cm and 35 cm) all were in four replicates. Data collected were analyzed using the generalized linear model of Statistical Analyses System (SAS 9.4) for the ANOVA. The results showed that there were significant differences (p<0.05) in the main effect of TP and SD as well as in the interaction effect between TP and SD on soil bulk density (Bd), saturated hydraulic conductivity (Ksat), volumetric moisture content (VWC) at different soil water potentials and plant available water (PAW). Greater Bd and Ksat were observed in DT which differed significantly (p<0.05) from other TP while the lowest was found in ZT with 6.5% reduction than DT. The result further showed no significant difference in terms of PAW (p>0.05) between the TP at the average depth of 15 and 25 cm, but they (TP) differed significantly at the average depth of 5 and 35 cm with the highest in ZT. Higher soil moisture content retained at all soil water pressure was found in ZT which differed significantly (p<0.01) form other TP. The research concluded that the best TP to be adopted in Hadejia in terms of improvement in physical and hydraulic properties is ZT practice.