All over the world, farmers choose different implements for tillage, which depend on crop type, soil type, the amount of plant residue from the previous crop, etc. Tillage implement selection is also affected by the availability of implements, power consumption, labor costs, and fund. In this research, the draft force, soil disturbance area, soil cone index, and fuel consumption were considered. The effects of rake angle, forward speed, and soil moisture content on the above-mentioned parameters were investigated. In this research, a comparison between the performance of a Fiber Reinforced Polymer (FRP) composite blade and a conventional steel blade was carried out. Tests were based on the split-split plot in a completely randomized design. The factors of soil moisture content, rake angle, and forward speed were included in three levels. Three levels for the soil moisture content (9.3, 13, 16.7 %), rake angle (20°, 30°, 40°), and forward speed (3, 5, 7 km.h-1), were considered. The FRP composite blade (on average in the desired range for variables) has reduced the draft force, fuel consumption, and soil cone index, 14.97%, 16.63%, and 35.08%, respectively, than the steel blade. Also, the soil disturbance area created by the FRP composite blade was 4.93% higher than the steel blade. Based on the results of this study, it is clear that the FRP composite blade has better performance rather than the conventional steel blade for the aforementioned test variables. The FRP composite is inexpensive than the steel, this leads to remarkable save money in the production of the FRP composite blade used in the chisel and combined tillage tools that is economical for the farmer and manufacturer.

Chisel plow is one of the tillage implements utilized to carry out conservation tillage practices; therefore, paying more attention to the force required for its. Operation is of much concern. To achieve this, a theoretical model was developed to estimate draft, specific draft, and drawbar power as required by a chisel plow. The results obtained from the developed model were compared with the reports of other studies and with the results of field experiments to validate the operation of the developed model. According to the results, the required draft force of a twelve-shank chisel plow, working at 30 cm depth in sandy, loamy, and clay soils were 27, 43 and 55 kN respectively and the required specific draft of this implement were 3.3, 5.1 and 6.5 N/cm2 respectively. The results were in agreement with the results attained from other studies, well with the results of ASABE standard (2011), therefore; it was concluded that the developed model is of the capability to estimate draft force of a chisel plow to an acceptable degree.

The purpose followed in the present research was to study and predict fuel consumption rate of tractor due to different aspect ratios for a chisel plow blade and to determine a general relationship between aspect ratio (D/W) and fuel consumption rate. An ITM-399 (81 kW) tractor and a mounted-type chisel plow of 9 shanks were employed. Two 5 and 10 cm width chisel blades were tested. The experiments were conducted in a clay-loam soil when at 9% of d.b moisture content, three levels of tillage depths (10, 15, and 20 cm), and three levels of travel speed (3, 4, and 5 km. h-1) in three replications. Results from F-test at 95% showed that three was no significant difference between the measured vs predicted values as compared with 1:1 line plot. Normalized Root Mean Square Error (NRMSE) and Mean Bias Error (MBE) indices were made use of to verify the accuracy of the equation. The results validated the precision of the attained equation.

Conventional tillage operations by either moldboard or disk plow need to be either changed or improved. Two types of combination plows were recently developed to modify the conventional equipment as well as to increase the efficiency. The aim of this research was to investigate the effect of the two combination plows as compared to conventional plow on power requirement and on specific draft. The experiments were conducted in a loamy textured soil with moisture content of 16-18% in Karaj region. Treatments consisted of moldboard + chisel plow combination, and disk + chisel plow combination vs conventional moldboard plow. Data was statistically analyzed using RCBD in three replications. Draft resistance, furrow cross section area, specific draft and drawbar power were either measured or calculated and then analyzed. The results indicated that draft resistance increased by.16.8%with moldboard + chisel and decreased 8.9% with disk plow + chisel as compared to conventional moldboard plow. However specific draft decreased by 29.8% and 10.4% for the combined plows respectively as compared with the conventional plow, this being due to soil disturbed area. Drawbar power for disk plow + chisel was noted to be maximum (26.2 kW).

Introduction1 Climatic variation particularly for participation is a constraint for the crops to reach their potential productivity under rainfed conditions. Therefore soil moisture preservation by means of tillage practices and improvement of soil physical criteria, particularly through enhancement of organic matter content is crucial. For this reason soil tillage must be managed in a proper way in order to fulfill this objective. Use of the right implements for this purpose under rainfed conditions together with retention of crop residue are practices most suitable for low rainfall environments. Tillage operation has a great impact on soil properties such as soil particle stability, soil aggregate and also soil water holding capacity. There are good evidences regarding yield improvement under rainfed conditions when implements such as chisel plow and sweep plow is used. Reduced tillage has been referred to as a proper practice under such conditions and degrees of no to minimum tillage have been proposed. These types of tillage combined with retention of crop residue which is referred to as conservation agriculture is being received more attention for the sake of soil conservation and moisture preservation. The purpose of the present study was to investigate these type of management for a rainfed wheatfallow rotation. Materials and Methods In order to study the effect of different tillage practices in fallow-wheat rotation and retention of crop residue on soil properties such as bulk density, soil aggregate, porosity, particle stability and moisture holding capacity and also crop criteria including yield, above ground biomass of wheat and weed under rainfed conditions, an experiment was conducted for two years (2013-2014 and 2014-2015 growing seasons) in Shirvan region, Northeast of Iran. The layout of experiment was strip plots based on a randomized complete block design and three replications. Tillage systems and retention of crop residue were the experimental factors with four levels of tillage (chisel, sweep, moldboard and no tillage) and three levels of crop residue retention (7, 3. 5 t. ha-1 and zero residue). Tisdal and Oades method used to determine the soil aggregates size distribution in dry and wet sieving conditions. To determine the soil bulk density, undisturbed samples were picked up from a depth of 0-10, and 10-20 cm and soil bulk density were determined after drying of soil in Oven for 48 hours at a temperature of 105° c. In order to evaluate the soil moisture at the end of the fallow year, sampling was done from each treatment in the depth of 0-20cm. During growth and after harvesting, the plant height, ear length, seed number per ear, thousand kernel weight, seed yield, and biological yield were determined. Results and Discussion Results showed that in general soil bulk density was higher at the depth of 0 to 10 cm compared with that at the depth of 0 to 10 cm for the experimental soil. Soil porosity followed a reserve trend of that of bulk density. Retention of crop residue caused a slower bulk density and a higher soil moisture content. Tillage with moldboard at different levels of crop residue retention caused lower weed biomass compared with other tillage operation. Soil practices size higher than 0. 5 mm were respectively higher and lower with moldboard plow. Seed yield and also above ground biomass were higher with moldboard plow compared with the conservation tillage practices. Despite lots of reports about the prominence of conservation tillage systems in comparison with moldboard tillage, the reason for the prominence of moldboard plow in comparison with conservation tillage in this experiment can be attributed to better seedbed preparation in moldboard tillage. The other reason for seed yield increment in the treatment of moldboard tillage in comparison with other treatments can be the effective control of weed plants, especially Russian Knapweed. Conclusion Despite contradictory reports about the effect of moldboard tillage on wheat yield in comparison with conservation tillage, the results of this experiment showed the prominence of moldboard tillage in contrast with the sweep, chisel, and no-tillage for wheat production. Under rainfer conditions retention of crop residue together with minimum level of soil disturbance seems to be a proper practice. This has been evidenced elsewhere and is confirmed somehow in our experiment too. This is mostly related to enhancement of water holding capacity of the soil.

The effect of different tillage methods on wheat yield in Iran's dryland conditions has been investigated in several studies. Most of the conducted studies only cover a small area (field experiments in one area), which in some cases have contradictory and incomplete results. The purpose of this research is to investigate the effect of conservation tillage (reduced tillage and no tillage) on dryland wheat yield using domestic studies with meta-analysis method. For this purpose, articles, research reports and student thesis between 1991 and 2021 were reviewed using key keywords related to tillage in the dryland wheat. Finally, after quality control, 29 studies were selected to compare minimum tillage method with conventional tillage and 22 studies were selected to compare no-tillage with conventional tillage using a random model. Based on the results, according to the effect size in the method of minimum tillage (SMD = +0.42) and no tillage (SMD = -0.43), it can be concluded that the minimum tillage method has increased wheat yield (+1.44%) and no-tillage method has decreased wheat yield (-7.7%) compared to conventional tillage method. It is suggested in dry lands, that one of the minimum tillage methods includes: 1- plowing with combinated tiller (chisel plow equipped with roller), 2- plowing with chisel-packer and 3-plowing with chisel plow + disk should be used instead of the conventional tillage (moldboard ploughing + disc + leveler) by observing plant rotation.

The aim of this research was to investigate performance of two combined plows compared to conventional plow. The experiments were conducted in a loamy soil texture with moisture content of 16-18% in Karaj region of Iran. Combination of moldboard + chisel plow and disk plow + chisel plow were compared with conventional moldboard plow as three treatments. Data was statistically analyzed using RCBD in three replications. Parameters of penetration resistance, bulk density, mean weight diameter and reversed residue percentage were measured or calculated and then analyzed. The results indicated that bulk density decreased 30.8% by moldboard + chisel plow particularly at depth range of 25-35cm. The results of penetration resistance (CI) confirmed the effect of this treatment on plowpan. Hence this combined machine can be recommended for a field with existing plowpan. Moreover diskplow + chisel treatment created the least clod size (MWD) in shallow soil layer. Therefore it can be recommend for reducing secondary tillage operation. The results of residue reversing noted that disk plow + chisel treatment left maximum of 68% crop residue. Therefore for conservation tillage system with residue reversing concern this combined machine is recommended.

The effect of six tillage systems consisting of 3 primary (moldboard, disk and chisel plows) and 2 secondary (disk harrow and field cultivator (twice)) tillage tools on corn production were studied in a factorial of two factors based on a completely randomized block design of six treatments and four replications. The experiments were conducted on Agricultural Faculty of Urmia University farms in 2002. The studied parameters were: tractor fuel energy consumption; soil penetration energy requirement, and yielded corn energy content. The results showed that the lowest and highest fuel energy consumption belonged to chisel plow+ disk harrow (962.9 Mj/ha) and disk plow (twice) field cultivator (1871.5 Mj/ha) respectively. The fuel energy consumption IN chisel plow and disk harrow treatments were found to be 30.1% and 23.3% lower than those for disk plow and field cultivator (twice) respectively. There were no significant differences observed among treatments for either corn grain or forage yields .For all treatments the calculated energy output for corn grain was between 36516.8 and 67638.3 Mj/ha, and for corn forage between 154580.1 and 212657.8 Mj/ha. For corn energy ratio (yields' energy/ consumed fuel energy) the highest were obtained from chisel + disk harrow treatment for corn grain plus forage, the lowest from moldboard plow + 2 times field cultivator treatment for corn grain, and disk plow + 2 times field cultivator for corn forage. The highest soil needed penetration energies for 5 to 40 cm depths belonged to the plots of disk plow + disk harrow, and the lowest to moldboard and chisel plow with disk harrow treatments. The results finally indicated that chisel plow + disk harrow (treatment A) with lowest fuel energy consumption, highest yielded energy and lowest needed soil penetration energy, was the most suitable tillage system.

In order to determine the effect of different tillage methods on grain yield and yield components of two wheat cultivars an experiment was conducted in Sanandaj in during 2005 and 2006-2007. Experiment was carried out in a split plot design based on RCBD with four replications. The three methods of tillage, including moldboard plow, chisel plow and no tillage were arranged as main plots, and two cultivars (Sardari and Azar 2) as the subplot. Also, the effect of different tillage methods on soil physical properties was evaluated with complete randomized blocks. The results showed that different tillage methods had significant effect on bulk density, porosity and soil cone index. The greatest bulk density and acone index was attained in chisel plow and no tillage system, respectively. The tillage methods and cultivars had a significant effect on yield and yield components. Sardary cultivars produced more grain (1624 kgha-1) than Azar2, statistically. The greater yield was attained in chisel plow than other tillage methods. Chisel plow improved soil water and soil physical properties. Using chisel plow resulted in maximum 1000 seed weight and maximum grain number in spike. Tillage methods and the cultivars had a significant effect on plant height and biomass.

The Compressing of soil due to traffic of agricultural machines and tillage tools which affect on the soil physical features and performance of agriculture production is going to become worst by mechanization of agriculture and vast application of tools. In this research, as a split plot experiment based on a completely randomized blok desing has been used and the effect of three types of tillage (moldboard plow-without moldboard plow and chisel plow) on two levels with and without subsoiling on selected plant and soil parameters was studied. Soil parameters under study included:1-moisture content 2-Bulk density of soil ,before and two months after planting in two depth of (0-10cm) and (10-20cm)and plant parameters included:1-The percentage of germination 2-plant dry matter. analysis of variance and Duncans multiple range test for comparision of means has been used. It was determined that in plots with subsoiler, the treatment of bz (subsoiler+moldboard plow)had a significant difference with az(subsoiler+chisel) and cz (subsoiler+without moldboard).On the other hand in plots without subsoiler a chisel showed a siginificant difference with b (moldboard plow) and c(without moldboard plow).