SOIL water retention curve is a key function that expresses SOIL vadose zone characteristics quantitatively. The direct measurement of this curve is time-consuming, laborious and costly. Therefore, many attempts have been made to predict water retention curve from other SOIL characteristics indirectly. Pedotransfer functions (PTFs) is one of the indirect methods. The objective of this research was to study the effect of GEOMETRIC MEAN DIAMETER (dg) and GEOMETRIC standard deviation (σg) calculated the basis of three and nine SOIL particle size classes in the prediction of SOIL water retention curve and Van Genuchten equations parameters applying pedotransfer functions. Consequently, 40 loamy SOIL samples, including 35 samples for prediction and 5 samples for validation, were randomly collected from Karaj area. Particle size distribution, bulk density, calcium carbonate and organic carbon percentages were determined with the hydrometery, cold, acid neutralization and Wally and Blacks methods, respectively. SOIL water retention curve was obtained using pressure plates. The best subset of independent variables for estimation of SOIL water retention curve and Van Genuchten equations parameters were selected by best subset regression command. Regression equations were obtained using multiple linear regressions. The results indicate that there is no significant difference in calculations in predicting point estimation PTFs by using dg or σg obtained from the data of three SOIL particle size classes or nine SOIL particle size classes. However, in the case of parametric estimation of water retention at tensions of 10, 33, and 100 kPa, using dg and σg obtained from the data of nine SOIL particle size classes and at tensions of 300, 500, 1500kPa than using dg and σg obtained from the data based on three SOIL particle size classes made more valid predictions. Statistical analysis indicated high validity of derived PTFs.

Measurement of SOIL moisture characteristic (SMC) curve is costly and time consuming. Point pedotransfer functions is one of the simple methods for estimating SMC curve. In this study, 20 SOILs were gathered from Marvdasht and Fasa regions in Fars province. Then, the SMC curve at suctions of 0, 3, 6, 9, 12, 30, 100, 500, 1000 and 1500 kPa, SOIL texture and SOIL specific surface area (SSA) of each SOIL were measured, and the MEAN GEOMETRIC SOIL DIAMETER (dg) of each SOIL was calculated. Then, regression equations were established for SOIL moisture content at mentioned suctions based on SSA and dg, separately. The results indicated that the point pedotransfer functions for suctions of 0-1500 kPa are appropriate.

The GEOMETRIC MEAN of particle DIAMETER (dg) of SOIL constituents and lime (CaCO3) are the most important subjects from the viewpoint of SOIL management and superintendence. Nowadays, remote sensing technology which has emerged walking with science development throughout the world, made the studying of SOIL properties (such as dg and lime) more facile, convenient and cost efficient. Investigation of SOIL-dg and lime has performed in Pol-e-Dokhtar by data sets of IRS, P6-LISSIII that has taken in September 7th 2007. Subsequently some processes like: Principal Component Analysis (PCA), Normalized Difference Vegetation Index (NDVI), SOIL Line Euclidean distance (SLED) and Unsupervised Classification (UnC), were carried out for acquired satellite data sets. By stratified randomized sampling (SRS) method and according to the false color composite (FCC) and photomorphic units (PMU) of the study zone image, eventually 95 sample points were selected and collected from 0-5cm of SOIL surface. Afterwards, dg and CaCO3 were determined for each point in the SOIL lab. By MEANs of multivariate regression operations finally showed pronounced relations (at 1% sig. level) between SOIL-dg and lime with green (adjusted R2: 0.78) and NIR (adjusted R2: 0.77) bands. As a result of this study, it is elucidated which GEOMETRIC MEAN particle DIAMETER and lime are able to affect SOIL spectral reflectance at the region and so it is possible to inquire these parameters using satellite and ancillary data.

SOIL structure and aggregate stability affect SOIL erodibility. There is a necessity for increasing aggregate stability against erosive factors such as wind and water. This study conducted on surface SOIL samples (0-20cm) collected from agricultural land susceptible to erosion located in the south of Fars Province. The experimental design was CRD with 10 treatments of control plot (without addition of SOIL amendments), pure gypsum, chopped wheat straw, animal manure, wheat straw and gypsum, animal manure and gypsum (1% w/w), cement (0.3, 0.6 and 0.9% w/w), and gypsum and cement (0.9% w/w) in 3 replicates. Amounts of SOIL aggregates in 53-4000 mm sizes were determined by wet sieving and MWD was calculated after one, four and seven months. After seven months, the results showed that the wheat straw, wheat straw and gypsum, and animal manure and gypsum treatments 2.7, 3.5 and 1.4 times respectively increased the MWD compared to the control. Generally, based on the results of this study, application of wheat straw with gypsum, wheat straw and animal manure with gypsum for increasing the stability of similar SOILs is recommended.

The GEOMETRIC MEAN particle DIAMETER (dg) and lime are two of the most important properties from the viewpoint of SOIL management. Nowadays remote sensing technology which has emerged walking with science development throughout the world has made SOIL study faster, more facile and more cost-efficient. An investigation of SOIL dg and lime was performed in Pol-e-Dokhtar area by use of four sets of spectral data of IRS P6, LISS III obtained from the Organizations of Geography of Armed Forces and Aerospace of Iran, in September 7th 2007. Subsequently, Principle Component Analysis, Normalized Difference Vegetation Index, SOIL Line Euclidean Distance and Unsupervised Classification were carried out for satellite data sets following image preprocessing operations. Through stratified randomized sampling method and according to the false color composite and photomorphic units of the main image, 95 samples were selected and eventually collected from 0-5cm depth of SOIL surface, likewise 43 samples from 5-20cm. Afterwards, dg and lime contents were determined for each sampled point in SOIL laboratory. By MEANs of multivariate regression operations there were eventually shown pronounced relationships (P< 0.01) between SOIL dg and lime with green (R2adj= 0.78) and NIR (R2adj= 0.77) bands in the first sampling depth. In addition, this was true for the second sampling depth with green (R2adj= 0.57), NIR (R2adj = 0.55) and red (R2adj = 0.59) bands with lower coefficients of determination. Consequently it has been substantiated with evidence that dg and lime contents are able to impress SOIL spectral reflectance. So it is possible to find out about these parameters using satellite and ancillary data.

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Homogeneity and uniformity of SOIL particles is a most potent factor which affects SOIL spectral signatures. GEOMETRIC standard deviation of SOIL particles (sg) exhibits the homogeneity of SOIL components. This study presents the influence of sg on spectral studying of SOIL GEOMETRIC MEAN particle DIAMETER as well as lime. The study was conducted in Pol-e-Dokhtar using the data set of LISSIII-P6, September 7th 2007. Subsequent to satellite data preprocessing, some such processes as: Normalized Difference Vegetation Index, Principal Component Analysis, SOIL Line Euclidean Distance and Unsupervised Classification were carried out on the acquired data. By stratified randomized sampling method and according to the false color composite as well as photomorphic units of the main image of the study area, 95 sample points were eventually selected and samples collected from 0-5cm of SOIL surface. GEOMETRIC standard deviation (sg), GEOMETRIC MEAN particle DIAMETER (dg) and lime (CaCO3) were later determined for each SOIL sample in the lab. Samples were accordingly divided into two parts on the basis of the computed GEOMETRIC standard deviation: the first, sg<10 (homogeneous SOIL samples) and the second, sg³10 (heterogeneous SOIL samples). Subsequently via correlation operations in SPSS for both groups, it was expressly displayed that for the first group (sg<10), dg and lime were very forcefully and explicitly correlated with the remotely sensed data, in comparison with the second group (sg³10). Hence, the GEOMETRIC standard deviation of SOIL particles (sg) in the study region can powerfully impress SOIL spectral reflectance.

In order to evaluate the effect of seed priming and seed size on physical and mechnical properties of onion genotypes a factorial field experiment based on a randomized complete block design with three replications was conducted in 2012 and 2013 cropping season at Agriculture and Natural Resources Research Center of East Azarbayjan, Iran. The experimental treatments included priming (at four levels: hydropriming, osmopriming (in %2 KNO3), priming with folammin amino acid (in 2%) and control (without priming), seed size (at three levels: small, medium, large) and cultivars (at two levels: RedAzarshahr and Zarguan). Following characteristics such as physical and mechanical properties include: arithmetic MEAN DIAMETER, GEOMETRIC MEAN DIAMETER, sphericity, frontal surface area, cross-sectional of area onion, static coefficient of friction, angles of repose and terminal velocity were studied. Analysis of variance for the measurd traits indicated that all characteristics significantly were affected by treatment and seed size. Results showed that seed priming and seed size improved physical and mechnical properties characteristics. The highest arithmetic, GEOMETRIC MEAN DIAMETER, frontal surface area, terminal velocity, were obtained from plant that primed with folammin amino acid 56.39,53.64, 36.27 mm 4.87 m/s, respectively, and the lowest were achieved from control plants. The highest repose angle filling and emptyin were obtained from control 46.7o, 23.17o respectively, and the lowest were achieved from primed with folamin. Also the highest static friction coefficient were obtained from control on plywood (1.6) and lowest were achieved from primed with folamin (0.67) on galvanized iron surfaces.