Critical rationalism faces difficulty in Karl Popper’s Socratic formulation: “I may be wrong, and you may be right, and by an effort, we may find the truth.” But the Socratic elenchus, using refutations, can only give us negative knowledge of general principles, which is not the wisdom we seek. Affirmatively, we can only find a collection of opinions to be coherent, which is one of many. Francis Bacon proposed an improved elenchus to find general truths. You must take up a limited topic to study, then cross-examine your evidence for and against its apparent nature. Experiments contrary to evidence and presumed knowledge are entered as self-contradictions in tables of opposition recorded in an “EXPERIMENTAL and natural history.” Such an account highlights a challenging puzzle if the account is to be made coherent. With enough problematized evidence, a coherent reading, or a solution of the puzzle, will be unique. Being both coherent and unique, it will be the truth about that limited reality being investigated. Unlike the method of hypothesis (“Anticipating Nature”), deciphering a coherent model is “Interpreting Nature,” allowing us to find a general truth on a limited topic. Isaac Newton achieved great success using Robert Boyle’s mechanistic version of this method. Using the “EXPERIMENTAL philosophy,” he discovered general principles of optics and astronomy.

Background and Objectives: Achieving to sustainable development is not possible without conservation of soil and water resources and reducing land degradation. On the other hand, in the low density-vegetation lands, biological soil crusts induced by the activity of soil microorganisms play an important role in conserving and improving of soil stability. However, in degraded lands, biological soil crusts are less developed. Thus, recently, biological soil crusts restoration by providing the appropriate conditions for increasing soil micro-organisms activities have been considered through the new biotechnologies applying such as soil microorganisms stimulants. However, the quick and lasting effects of soil conservation strategies is the most important criteria in the selection of management measures. Hence, this study was planned to assess performance of a soil bacterial stimulant nutrient (named B4) as completely bio-amendment in reducing soil loss and runoff at laboratory and small PLOTS conditions. Materials and Methods: In the study, the EXPERIMENTAL PLOTS were filled by collected soil of degraded and erosion-prone area of Marzanabad-Kandelus region based on the layering, grain size and bulk density of the native soil area. The solution with 15 g calcium acetate l-1 distilled water (dw), four g yeast extract l-1 dw and five g dextrose l-1 dw was prepared as B4 stimulant nutrient. Then the B4 was spraied on PLOTS. To this end, two treatments of B4 injection and control with three replications were considered. After 15 days, in the Rain and Erosion Simulation Laboratory of Tarbiat Modares University, the simulated rainfall was carried out with during of 100 min and intensity of 50 mm h-1 according to high-erosive rainfall of the native area. Then, the soil loss and runoff components were measured. Results: Statistical comparison of results indicated that injection of B4 stimulated the proliferation of soil bacteria and, as a result of the effect of bacteria on some soil characteristics, improved the soil loss and runoff components, which was more effective in reducing soil losses than surface runoff. The start time and time to peak of runoff at the control PLOTS (without injection) were increased significantly (P<0. 05) from 24. 83 to 49. 22 min and from 78. 66 to 92. 66 min at the stimulant nutrient PLOTS, respectively. Also, the volume and peak of runoff, soil loss and sediment concentration at the stimulant nutrient PLOTS were decreased significantly (P<0. 05) at rate of 88, 92, 95 and 35%, respectively compared to control and measured as 275. 66 and 18. 66 mm, 0. 49 g and 1. 79 g l-1, respectively. Conclusion: According to the present results, the restoration and enhancement of biological soil crusts in low density-vegetation and degraded lands through stimulating and increasing population of soil micro-organisms using micronutrient stimuli such as B4 as has been considered as a biological, efficient and quick strategy to conserve soil and water resources. However, further researches are required to achieve reliable strategies by using other microbial stimulants and evaluating their durability during successive and long-term precipitation.

Soil Erosion due to water is a major environmental problem in many parts of the world. Accurate estimation of water erosion is very important for the assessment of potential soil loss and storage capacity in reservoirs due to sediment deposition. The physically based Water Erosion Prediction Project (WEPP) model provides event-based runoff, erosion and sediment yield estimates. In this study surface runoff and soil loss simulated by the WEPP hillslope model were compared with measurements from two EXPERIMENTAL PLOTS containing rangeland vegetation. These PLOTS were 12.5 m long and 2 m wide with slope gradient of 34%. Results showed, in general, WEPP hillslope model simulated fewer runoff events than measured data. The model tended to present better results when effective hydraulic conductivity was calibrated. Correspondence between measured and simulated runoff and sediment data were represented model efficiency coefficient 0.86 and 0.87, respectively.

Background and Objectives: Soil erosion is a major global challenge that its control by appropriate and proportionate methods is necessary. In recent years, various studies have been carried out using amendments and chemical stabilizers to reduce the detrimental effects of runoff and soil erosion. Environmental problems, low efficacy and time-consuming, low availability and high volume requirements have challenged the use of amendments in the usual form. Therefore, due to the proper performance of the amendments to reduce runoff and soil loss, improving the quality of the amendment is inevitable. Nowadays, various wastes are currently produced in important industries, including wood and papermill. In this regard, the fine corrugated and small particles in the effluent of paper mills can be mentioned. Residual fine amendments is a part of fibers that are unavoidably crushed in paper production and recycling processes. Therefore, due to the problems caused by the excessive amount of fines in the process of paper production and the ability to store water in the soil, it seems that it can be used as a natural amendment to reduce runoff and soil loss. Materials and Methods: The present study was carried out to investigate the effectability of runoff generation and soil loss from fine corrugated amendments at small EXPERIMENTAL PLOTS. To conduct the study, the soil carried out from the marginal area of the Marzanabad-Kandalous region located in the west of Mazandaran Province. The soil was air-dried and then crossing a 3 mm sieve to put into 50×50 cm PLOTS with a height of 30 cm was filled from the bottom to a depth of 18 cm of mineral pumices as a drainage layer and for the top layer of soil 2 and 8 mm. Treatments were studied at three levels of 0. 5, 1 and 1. 5 )L m-2( and each with three replications in liquid form and uniform spraying on 18 PLOTS with pure water additive and control (dry) and in laboratory scale under rainfall simulation was performed with intensity of some 70 )mm h-1( and duration of 30 minutes. Results: The results showed that use of fine amendment with three levels of 0. 5, 1 and 1. 5 )L m-2( decreased runoff volumes (P>0. 05) and soil losses (P<0. 05) of-35,-5 and +15; 47, 84 and 71% compared to those of the treated PLOTS by fine, respectively. Conclusion: The results of this study show that the application of biocompatible amendment from wastewater of papermills is recommended to prevent entering into the water and soil resources in order to reduce runoff generation and soil losses in sensitive areas of the country facilitating sustainable development. It further leads to reduce runoff generation and soil losses in sensitive areas of the country facilitating sustainable development.

The effective utilization of wastes in different forms is an inevitable strategy for such miscellaneous goals as runoff management which also leads to sustainable development. To this end, superficial application of biochar produced from industrial wastes as mulch may act as a bio-economic approach to improve soil conditions and some consequent increment in infiltration. Towards this attempt, the present study was formulated to produce biochar from Kaleh Factory wastes and to apply it as mulch. Biochar was applied in three levels of 400, 800 and 1200 g m-2 on small EXPERIMENTAL PLOTS filled with a rangeland soil prone to erosion of Marzanabad Region, northern Iran, to improve soil permeability and runoff components. The rainfall was simulated with intensities of 50 and 90 mm h-1 after a span time of 35 days on biochar application in the Rainfall and Erosion Control Laboratory of Tarbiat Modares University. The infiltration and runoff rates were continuously monitored using volume balance method. According to the results, water infiltration to the soil and runoff rates from treated PLOTS with 400, 800 and 1200 g m-2 of biochar were 23, 31 and 32% for rain intensity of 50 mm h-1, and 21, 23 and 24% for rain intensity of 90 mm h-1, respectively more (p<0. 01) than those reported for control PLOTS. The volume of runoff for the same treatments were also 56, 62 and 67 %, and 59, 64 and 65 % for rain intensities of 50 and 90 mm h-1, respectively, less (p<0. 01) than those reported for control PLOTS. However, the time the runoff to be initiated was reduced in all the treated PLOTS. The results further verified that the biochar produced from food industry factories could improve the hydrological components of the degradable soils.

Introduction Soil erosion by water is one of the most common environmental problems worldwide and is considered a serious risk for sustainability in developing countries. Water erosion on a global scale is one of the most critical types of soil and environmental degradation due to its geographical extent and ecological effects. In this regard, effectively controlling sediment load is an important component in watershed management. In the formulation of a watershed management strategy, the estimation of sediment delivery ratio (SDR) plays a significant role. SDR is defined as the sediment yield from an area divided by the gross erosion of that same area. SDR is expressed as a percentage and represents the efficiency of the watershed in moving soil particles from areas of erosion to the point where sediment yield is measured. One of the problems in estimating the SDR in watersheds is the lack of proper information on the amount of soil erosion and sediment yield. In this context, the Sanganeh soil conservation research station, having measured soil erosion and sediment yield of small watersheds, is a suitable place to evaluate the accuracy of the RUSLE model and estimate the ratio of sediment delivery on the scale of small watersheds. The current research aims to achieve two goals: a) determining the accuracy of the RUSLE model in estimating soil erosion based on the measurements in the erosion PLOTS, and b) estimating the SDR using the estimated soil erosion values as well as the sediment yield measured at the outlet small watershed are planned. Materials and Methods Considering the importance of soil erosion and the study of sediment processes in semi-arid rangeland ecosystems, the Khorasan Razavi Agricultural and Natural Resources Research Center (KANRRC) assessed some micro-watersheds for the collection of storm-wise runoff and associated sediment. The Sanganeh research micro-watershed, located 100 km from Mashhad City (northeast Iran), is one of the watersheds selected for this study. The watershed area, the longest waterways, and the mean slope of the watershed are 1. 2 ha, 145. 0 m, and 31. 2%, respectively. The study watershed consists of semi-arid rangeland dominated by Bromus tectorum and Artemisia diffusa, with a coverage of 50%. The soil is Entisol and Aridosol, young, with a maximum depth of 30 cm. The mean electrical soil conductivity (EC), soil organic matter (OM), clay, sand, silt, and surface rock fragments of soils are 1. 81, 1. 57, 10. 6, 54. 7, 34. 7, and 5%, respectively. In this research, three EXPERIMENTAL small watersheds with areas between 4300-12000 m 2 were selected along with the erosion PLOTS in them. Then, 24 rainfall events related to two periods of 2006-2009 and 2016-2018 were recorded along with the corresponding data of runoff and sediment in watersheds and PLOTS. In this study, water flow and sediment yield were monitored at the main outlet of the micro-watersheds and PLOTS. The runoff volume was calculated after each storm event by multiplying the depth of collected water, measured using an iron ruler at five points in the tank (corners and central), by the surface area of the collector. The collected runoff and sediment were then mixed thoroughly and one sample was taken to determine sediment concentration and sediment yield. Then, by collecting the required information (includeing rainfall erosivity, topography, conservation practice, soil erodibility, and cover-crop management factors), the RUSLE model was run and compared with the observation data of the PLOTS. The storm-wise soil erosion predictions were compared with observed data based on the criteria of the coefficient of determination (R 2 ) and relative estimation error (RE). In the following, by modifying the RUSLE model and observing the sedimentation data of the studied watersheds, the value of the SDR was estimated. Results and Discussion After collecting the required information, the RUSLE model was implemented at the plot scale. The accuracy of the model was evaluated using erosion plot data, which was not confirmed due to huge overestimations of RUSLE. Next, to achieve more accurate results, regression types (linear, exponential, power, etc. ) were used between the observed and estimated values of soil erosion (RUSLE). After applying the correction coefficient, this model was able to estimate the average erosion rate of the whole period are 12, 17, and 2% for E1, E4, and E6 watersheds, respectively, which is within the acceptable range of soil erosion modeling. Therefore, it can be said that the accuracy of the modified RUSLE model (by regression model) in estimating the average soil erosion during the period is higher than the event-based scale. Also, the prediction of maximum event estimation error for E1, E4, and E6 watersheds was 25. 7, 35. 8, and 21. 6%, respectively. After evaluating the accuracy of the RUSLE model at the plot scale and in order to know the amount of soil erosion at the watershed scale, the values of L, S, K, and C factors for the watersheds were calculated based on a weighted average and entered into the modified model. Therefore, the results of the RUSLE model were generalized to the watershed scale. In the final stage, by dividing the amount of erosion by the corresponding amounts of sediment yield measured at the outlet of watersheds, the ratio of sediment delivery was calculated. The average SDR of the entire period in the E1, E4, and E6 watersheds are 42. 2, 41. 5, and 39. 7%, respectively, and in the maximum events, it is one or two percent higher. Conclusion Overall, the results of this research showed that using the modified RUSLE model, it is possible to estimate the average soil erosion in the Sangane soil conservation station and also estimate the SDR. Therefore, this approach can be used in executive programs in similar areas. According to the obtained results, the classification of rainfall data based on the rain erosive factor and then the evaluation of the RUSLE model can provide more accurate results. In addition, in this research, due to the small area of the watersheds, waterway processes did not play a role in the deposition and transfer of eroded soils. It is also suggested that similar research could be done in larger watersheds. Finally, considering the determination of the SDR in this area, it is recommended to evaluate the accuracy of the EXPERIMENTAL methods for determining the SDR.

Accuracy of sugar beet trials, particularly variety comparisons, depends on several factors including; statistical design, treatments oriented, EXPERIMENTAL techniques, and replication numbers in order to estimate various components of a statistical model precisely. Testing agronomic treatments or evaluating new varieties for plant protection (PVP) or value for cultivation and use (VCU) under both field and glass-house conditions needs a reliable statistical design. There are many factors and circumstances like response of genotype, location, year, agronomic techniques etc. that affect performance of a sugar beet trial. Some of these factors are usually unknown before conducting the experiment that may influence the precision and accuracy of a field experiment. In addition to these, uncontrolled variations are usually summed in the EXPERIMENTAL error. Type and quantity of the “variance of error” may be originated from different sources in which mainly are the precision of measurements and techniques as well as choice of the EXPERIMENTAL design. The EXPERIMENTAL design is also function of a number of other factors. When using RCBD, PLOTS should be oriented in such a way to minimize soil variation, nutrient and pesticide residuauls within a block. In practice, treatments should be applied in parallel to the directions of blocks of a trial to minimize variance of error. A well-prepared field trial is effective in reducing the EXPERIMENTAL error; however, a good and homogenous field emergence depends on the quality of seedbed preparation. Size of plot and plant number within a plot is essentially important. Homogeneity of a plot depends on its size; too big PLOTS increase the error and too small PLOTS would leads to lack of precision. An optimum plot size and average number of plants at harvest time needs to be sufficient to stabilize the error at a low level. If a trial carried out at different locations for several years, effects of these factors must be considerd precisely. Random or fixed effects of entries are very important for the estimation of variances. In sugar beet variety trials, it is common to apply either RCBD or lattice designs, each of them has advantages and limitations. In order to reduce variance of error and consequently increasing EXPERIMENTAL accuracy of variety comparison, complete block or incomplete blocks (lattice design) should be arranged on a homogenized soil. Since there are close competitions among commercial sugar beet varieties, an appropriate statistical model based on the type of variation sources is essential to select superior varieties within a trial and increases the efficiency of selection for superior lines and varieties in plant breeding programs.

The proper management of a watershed depends on recognition of effective elements and investigation of their behavior in different conditions. Till date, many researches have studied the role of topographical general characteristics on hydrologic behaviors. Whereas, the changeability of hydrologic properties under different conditions, especially in Iranian watershed has been rarely taken into account. This research aimed to assess the role of slope steepness and aspect on runoff and sediment characteristics in Educational and Research Watershed of Tarbiat Modares University (Kojour) watershed located in southeastern of Nowshahr Township, Iran.Experiments were conducted by using a pressure rain simulator with an intensity of 1.6 mm min-1 and a plot in dimension of 30´30 cm in two slope ranges i.e. £ 25 and >25% and eastern and western aspects. These experiments were done in three replications and in particular places on monthly basis from October 2008 to June 2009. The study was formulated in factorial and Latin square designs and the associated results were then analyzed with the help of SPSS 17 software package. Results showed that the affect of slope on runoff volume was significant (p<0.04) so that, in contrary to oft reported, the volume of runoff was lower in steeper slope.Slope steepness and aspect had also alterative significant (p<0.05) effects on sediment yield. Generally, the higher slope with coarse soil texture and less available sediment, the lower sediment yield with greater amounts in eastern slope.

Soil water content (SWC) is an important physical factor that plays an essential role in many processes such as infiltration and soil erosion. This study was conducted to investigate the effect of SWC on runoff and soil detachment from rills in coarse-grained soils in the semi-arid region. For this purpose, furrows with 6 m in length were installed in five rainfed farms with different slope steepness (6. 1, 10. 6, 14. 8, 20. 7 and 27. 1%) treated with four moisture levels including air-dried (AD), between air-dried and field capacity (AD-FC), field capacity (FC) and saturation point (SP) in a completely randomized design witht three replications. Flow rate with a discharge of 2 L min-1 was used to investigate soil detachment from the farms. The soils were coarse texture (having 5675% sand) and rocky (having 22-57%) with unstable structure and high infiltration rate. Based on the results, soil detachment decreased with increasing SWC in 6. 1, 14. 8 and 20. 7 % slopes. The highest soil detachment rate (g m-2-1 s ) in these lands was observed in AD-FC (0. 01), AD (0. 306) and AD (0. 0045), respectively. By increasing SWC, the continuity and stability of soil mass of furrow increased, and runoff occurred mostly as subsurface flow in the rills. Surface runoff as well as the soil particle detachment decreased in the rills. Therefore, in the semi-arid slopes with coarsegrained soil, soil detachment rate decreases with increasing SWC.

Due to the time variation of sediment concentration and runoff volume during storms, and on the other hand, the lack of control and study of storms in field conditions for analyzing hydrographs and sediment graphs changes in different soil moistures, the investigation of these variables has special importance in laboratory conditions. Also, the results showed that the use of soil conditioners in laboratory conditions in order to determine their effect has not been considered for preparing hydrograph and sedimentograph. Therefore, the present study was conducted to investigate the effect of biochar derived from sewage sludge with rates of 0. 4, 0. 8 and 1. 6 t ha-1 proportional with cover level of 25, 50 and 75 percent on hydrograph and sedimentograph in different soil moistures including air-dried, 15, 20 and 30 percent, with rainfall intensity of 50 mm h-1 and rainfall duration of 10 min after time to runoff in laboratory conditions. The results showed that the biochar conditioner with various rates toward control treatments had significant effect on hydrograph and sedimentograph changes. Also, the biochar treatment with rate of 1. 6 t ha-1 in different soil moistures has significantly more effective toward on hydrograph and sedimentograph changes. The results also showed that the correlation coefficient between biochar amounts with time to runoff, runoff coefficient, and soil loss and sediment concentration variables was significant in confidence level of 99 percent.