B. Shiranpour; A. Bahrami; M. Shabanpour
Abstract
Due to high organic matter and strong structure, the forest soils in Guilan province are potentially productive. This study was conducted to show the effects of land use change on soil fertility in four different sites in Guilan province where the location of tea garden and forest have the same physiography ...
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Due to high organic matter and strong structure, the forest soils in Guilan province are potentially productive. This study was conducted to show the effects of land use change on soil fertility in four different sites in Guilan province where the location of tea garden and forest have the same physiography and parent material. At any site three soil samples with randomly method were collected from a depth of 20cm from the soil surface and total Nitrogen, available Phosphorous and Potassium, exchangeable form of Calcium and Magnesium contents and C/N ratio were measured. The results showed that after 10 – 40 years of the land use change (forest to tea gardens) the amounts of these elements had been significantly reduced (P>0.01). Also the effect of sites on this reduction had been significant,this means that land use change in different sites had various effect on characteristics that were studied. In contrast, C/N ratio didn’t show significant difference.
S. Akhavan; M. Shabanpour; M. Esfahani
Abstract
In order to study the effect of soil compaction on root and shoot growth of wheat plants (Shahriar variety), a greenhouse pot experiment was conducted in Guilan University. The study design was factorial with completely randomized in three replications. Treatments included three compaction levels; (normal ...
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In order to study the effect of soil compaction on root and shoot growth of wheat plants (Shahriar variety), a greenhouse pot experiment was conducted in Guilan University. The study design was factorial with completely randomized in three replications. Treatments included three compaction levels; (normal compaction, compaction of ten percent and twenty percent) and two type of soil texture (clay and sand) will include 18 pots. Soil mechanical resistance index measured with the device influence the resistance gauge significant differences among treatments indicated. Root and shoot traits measured included plant fresh weight and total shoot dry weight, leaf dry weight (LDW), stem dry weight (SDW), root fresh weight (RFW), root dry weight (RDW), leaf area (LA), root area (RA), root volume (RV), root length (TL), root dry weight ratio of shoots, leaf area to root ratio (LA/RA), root length density (RLD), root surface area density (RSD), root mass density (RMD), dry root mass density (DRMD) and nitrogen content of roots, significant difference in the levels indicated treatments. The results showed that increasing the compaction of soil are affected characteristics related to the shoot and root of wheat plants, and twenty percent of the compaction (influence resistance 1200 KPa in the clay soil and 762.76 Kpa in the sandy soil) is limited roots and shoots growth than the natural soil.
F. Meskini Vishkaii; M. Shabanpour; N. Davatgar
Abstract
Abstract
The saturated hydraulic conductivity (Ks) is an important physical property of soil. The direct measurement of this property in soils is a difficult and time consuming process. Pedotransfer functions (PTFs) provide an alternative by estimating soil parameters from more readily available soil ...
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Abstract
The saturated hydraulic conductivity (Ks) is an important physical property of soil. The direct measurement of this property in soils is a difficult and time consuming process. Pedotransfer functions (PTFs) provide an alternative by estimating soil parameters from more readily available soil data. The objective of this study is to determine effective factors on soil hydraulic conductivity using multiple-linear regression methods and to determine direct and indirect effects of input soil properties of model using path analysis method. 70 soil samples with medium to heavy texture were randomly collected from paddy fields in Guilan province after harvest of rice crop. Range of pH indicated acidic to neutral condition of paddy soils. Results showed that regression equation using geometric mean and standard deviation of soil particles diameter (dg and g), bulk density (b) and soil moisture at field capacity (0.033) as input variables, can estimate hydraulic conductivity with a good accuracy ( RMSE= 0.5 and R2adj=0.84). Although correlation between bulk density and saturated hydraulic conductivity was positive, but according to path analysis results, direct effect of bulk density on Ks is negative. Moreover the highest direct effect of soil properties on Ks in paddy soil was through soil water content at field capacity that indicates importance of this factor to predict saturated hydraulic conductivity.
Keywords: Pedotransfer functions, Geometric mean of soil particle diameter, Field capacity
