EURASIAN JOURNAL OF SOIL SCIENCE

9 - 19

Authors: Milad Mirzaei Aminiyan, Hamideh Hosseini, Amin Heydariyan

Soil microbial communities and their related characteristics are an important agent for soil fertility, productivity, and sustainability. Also, they are useful indicators of soil quality and life index in agricultural systems. The objectives of this study were the effect of nanozeolite and plant residues on soil microbial communities and their characteristics and also, the assessment of incubation timing on soil microbial properties. Soil microorganisms are very important in the decomposition of plant residues. In this regard, the soil samples were treated by nanozeolite (0, 10 and 30% Weight), Alfalfa and wheat straw (0 and 5% Weight). The treated soil samples were incubated in lab condition for 90 days. The result of this study showed that Bacterial, Fungal, and Actinomycete populations increased by the addition of 30% of nanozeolite and 5% of plant residues, especially alfalfa straw. Also, the addition of nanozeolite and plant residues treatments improved MBC, BR, and SIR as microbial characteristics. These parameters increased after 30 days of starting incubation, then decreased until the 75th day and finally increased slightly on the 90th day. In fact, the addition of nanozeolite and plant residues into the soil had positive effects on improvement of carbon pools and increasing carbon sequestration in it. Applied nanozeolite and plant residues in soil, improved carbon pools and increased carbon sequestration in soil. Also the application of nanozeolite and plant residues especially alfalfa straw had positive effects on improvement of soil biological communities and characteristics.

30 - 42

Authors: Rubya Shabnam, Md.Toufiq Iqbal

Plants are not uniform in their nutritional requirements, most of them survive under adverse conditions of humidity, temperature, and nutrients. Because they are genetically adapted to their habitats and even some varieties of the same species show differences in absorption, translocation, accumulation and nutrient use. This study is aimed at examining the phosphorus (P) status in the different parts of wheat (Triticum aestivum L.) plant and its influence on plant growth and P translocation in a split-root soil culture. KH2PO4 was used as the source of phosphorus for the different level of P application. Two recently BARI developed wheat varieties namely BARI GOM 25 and BARI GOM 26 were used as testing plants. . Result showed the growth parameter increased with the increase of P application. Likewise, P uptake by wheat plant also increases with the elevated P application. However, no significant differences were observed between wheat varieties irrespective of growth and P uptake by wheat plant. Moreover, elevated P concentrations in the shoot of wheat plants probably provide more P for shoot unloading of P and for P assimilation in the controlled roots. This phenomenon results in increased P concentrations in the roots of wheat plants that mean translocation of P in the roots. These findings indicate that the added soluble P increases the absorption of nutrients from the soil solution. So, this study concluded that the application of elevated P in split-root system is efficient both for increasing shoot development and root growth and plays significant role in thePtranslocationwithin the wheat plants.

51 - 58

Authors: Mert Acar, Ismail Celik, Hikmet Günal

The stability of aggregates plays a vital role in preserving and long term storing of soil organic carbon (SOC). In this study, the long-term (2006-2014) effects of six tillage systems on aggregate-associated SOC were investigated in a field experiment conducted under Mediterranean conditions. The tillage treatments were; conventional tillage with residue incorporated in the soil (CT1), conventional tillage with residue burned (CT2), reduced tillage with heavy tandem disc-harrow (RT1), reduced tillage with rotary tiller (RT2), reduced tillage with heavy tandem disc harrow fallowed by no-tillage (RNT) for the second crop, and no tillage (NT). The most frequently encountered aggregates in all tillage systems were at 4.0-2.0 mm size and the least frequently found aggregates were 1.0-0.5 mm. The mean weight diameter (MWD) value increased in the NT compared to the conventional tillage practices at the rates of 137% and 204%, respectively at 0-15 cm soil depth. Aggregate-associated SOC contents in 0-15 cm depth were higher under conservation tillage systems. However, the highest SOC at 15-30 cm depth were greater mainly in conventional tillage systems as 9.4% for both CT1 and CT2. The results indicated that conservation tillage systems had greater aggregation and carbon storage at the soil surface.

64 - 72

Authors: Henry Oppong Tuffour, Joseph Asare, Gilbert Mcphelan Nutakor

Field and laboratory infiltration measurements using infiltrometers have been the only methods of effectively determining the infiltration rates of soils. Infiltration is mainly controlled by soil hydraulic properties, especially the hydraulic conductivity. Due to the ease with which the saturated hydraulic conductivity can be determined, it is often preferred to the unsaturated hydraulic conductivity in hydrological studies. It is well known that, at saturation the steady state infiltrability controls the infiltration process. Thus, it is very clear that the saturated hydraulic conductivity Ks and steady state infiltrability Ko may be closely related in one way or the other, as suggested in some few studies, wherein functions have been developed to relate these two parameters. However, these functions are often site specific and do not always carry out accurately all the time. Determination of Ko can be tedious and time consuming, whereas Ks can be easily determined in the laboratory. The present study aimed to assess the predictability of a modified Philip’s equation by substituting Ks for Ko. In this study, field infiltration measurements were conducted in two soil types under three different land use systems with a single ring infiltrometer. Field and laboratory hydraulic and hydrologic experiments were conducted on soils in a turf grass, an arable land and a pastureland in the Kwame Nkrumah University of Science and Technology, Kumasi, Ghana. Goodness-of-fit was used to compare the measured and predicted cumulative infiltration amounts from both Ko and Ks. The results showed that there was a robust relationship between the measured and predicted cumulative infiltration amount values from the Philip’s and modified Philip’s equations, respectively for all three fields. However, the use of Ks in place of Ko produced the best outcome in all the study areas. Thus, substituting Ks for Ko in the Philip’s infiltration equation can better predict cumulative infiltration amount. The proposed modified Philip’s infiltration equation and the key parameters (i.e., Sθ and Ks) provide new understanding into the realistic flow processes in soil. Furthermore, the Ks in the new equation is very close to the measured Ko.

87 - 92

Authors: Tayfun Aşkın, Selahattin Aygün

In this study, we applied hazelnut husk waste that was composted by using microbial biotechnological techniques into soil in the field conditions. The hazelnut husk compost (HHC) was applied in two hazelnut orchards having different textures such as sandy loam (SL) and clay loam (CL) soils and used different application rates (0, 1.25, 2.5, 5.0, 7.5 and 10 t da-1). Soil sampling was done four times in a year (spring, summer, fall and winter). We investigated the effects of HHC on soil water holding capacity related to available water content of soil at both field capacity (FC) and permanent wilting point (PWP) with weight basis. Soil moisture coefficients were determined by using pressure plate and indicated as percentage weights at FC (-33 kPa) and PWP (-1500 kPa). Our results showed that HHC doses, sampling periods and soil textures effected soil water holding capacity at both FC and PWP. In addition, FC and PWP were found the highest at 10 t da-1 application dose. Findings of this study, the huge importance of HHC that related to protect soil water without harmful to the environment emphasized.