Engineering properties of soils besides the chemical and biological properties can be a tool for justifying the behavior of soil. In this study bulk density, hydraulic conductivity, soil penetration resistance and Shear strength were measured. Different levels of depth and puddling intensity and their interactions on the properties in randomized complete design with three replications in a factorial experiment was investigated. Results indicated puddling intensity decreased the soil hydraulic conductivity, bulk density, penetration resistance, shear strength and with increasing depth, bulk density, penetration resistance and shear strength increased. The changes in bulk density were 0. 68-1. 32. The highest and lowest hydraulic conductivity were reported 0. 3 and 8. 5 in treatment P0 depth 10 cm and treatment P2 depth 30 cm respectively. It can be said that puddling treatment P1 is more suitable than treatment P2 to keep moisture, reduce physical and mechanical damage, energy required to prepare the paddy fields.

To optimize the puddling operation in paddy land preparation, the effects of puddling methods and times on some soil physical properties and grain yield and yield components of rice variety Hashemi were evaluated in this research. The experiments were conducted in a split block design in three replications with two factors, puddling method in four levels (power tiller conventional puddler, power tiller rotary puddler, power tiller cono-puddler and tractor-mounted rotivator) and puddling times in four levels (from once to fourth) in a silty clay soil. Results revealed that the minimum bulk density (0.801 g.cm-3) and maximum penetration depth of falling cone (13.31 cm), weeding efficiency (60.57 %) and puddling index (54.53 %) was related to puddling with tractor-mounted rotivator and the maximum bulk density (0.872 g.cm-3) and the minimum of weeding efficiency and puddling index (51.52 and 44.50 %, respectively) was belonged to power tiller conventional puddler. Increasing of puddling times from once to fourth, decreased the bulk density from 0.882 to 0.795 g.cm-3, but increased the penetration depth of falling cone from 9.04 to 12.39 cm and also weeding efficiency and puddling index from 51.78 to 56.54% and from 45.21 to 51.23 %, respectively. The grain yield in puddling with tractor-mounted rotavator and power tiller rotary puddler (3429 and 3401 kg.ha-1, respectively) were significantly (P<0.01) higher than those of power tiller conventional puddler and power tiller cono-puddler (3346 and 3332 kg.ha-1, respectively). The grain yield increased from 3322 to 3408 kg.ha-1 with the increasing of puddling times from once to fourth, however there were no significant differences between twice, thrice and fourth puddling. In total, results of this research revealed that twice puddling with power tiller rotary puddler or tractor-mounted rotavator can be considered as a proper treatment for puddling operation in silty clay soils similar to experimental site.

The aim of this research was investigation of non-chemical control of weeds and prevention of rice yield reduction with appropriate land preparation such as puddling. A filed experiment was conducted in 2011 and 2012 growing seasons in Tonekabon’s rice research station (Chaparsar) in Mazandaran province. The experiment layout was a factorial experiment based on randomize complete block design (RCBD) with three factors including type of equipment (rastcawel and rotivator), time of puddling (10 and 20 days before transplanting) and number of puddling (one and two times) with three replicates. Results of combined variance analysis showed that effect of year on tiller speed, time of puddling and grain yield were statistically significant. Tiller speed was affected by kind of tool and second pudlling time. Effect of pudlling frequency on number of filled seed was significant. Number of weeds at 2 M-2 and grain yield was not affected under applied three factors. The maximum of tiller headway speed (2.27 m.s-1) was obtained with one time of puddling by rotivator. minimum time of puddling treatment (4.47 min/plot) was achieved using two time of puddling at in 20 days before transplanting. Mean of rice grain yield was 3689.4 kg/ha.

Using chemical weed control methods play an important role in the reduction of herbicide use as well as environmental protection. nowadays Appropriate land preparation, specially puddling has been known as one of the best factors for weed control in rice fields. plowing in late winter and then in one or two weeks before trans planting in spring, is the current method of plowing in Guilan province. Number of puddlings and type of equipment used, depends on conditions and farming system in different sites in Guilan province. since  the  Kind of equipment and number of secondary tillage's affect weed density, an experiment was conducted in 2005. The treatments included: Conventional method with once and twice puddling, the second puddling after a 10 day interval puddling, method once or twice, with a rotivator as well as puddling once or twice, with cone- puddler. These trials were conducted in rice fields in Taki Tazeabad village with 3 replications. Main noxious weeds were: Echinochloa crus-gali, Cyperus rotundus and Alisma plantago-aquatica. The results indicated that, number of tillage and kind of equipment affected weed population and density. The best treatment was conventional method with two puddlings which reduced weed density 2.1 times in comparison with the worst treatment that is, cone puddler with once puddling.

Puddling is the most common method of land preparation of paddy fields in lowland rice cultivation. Puddling affects the physical, chemical and biological properties of soil and these changes are effective on rice growth. The soil that is more susceptible to changes in structure is easier to puddle. This research was aimed to investigate the effects of different puddling levels on moisture content and bulk density of three dominant soil textures of paddy fields in Guilan province. The experiment was designed as factorial with completely randomized blocks having three replications. Undisturbed soil samples were taken from 3 different soils (silty clay, clay loam and loam) with cylindrical samplers with diameter and height of 50 cm. The soil samples were puddled by a laboratory apparatus. The puddling treatments were: P0 (no puddling), P1 (low puddling), P2 (medium puddling) and P3 (high puddling). Soil moisture content and bulk density of all soil samples was measured every 24 hrs for six days. Analysis of variance showed that puddling had significant effect (p<0.05) on soil moisture content and bulk density. The water content of the puddled layers decreased with an increase in settling time. During drying period, P0 dried faster than P1, P2 and P3. In P0 to P3 treatments of the loamy soil, the moisture content decreased about 22.6, 16.3, 14.8 and 9.6% after 144 hrs past puddling, respectively. The trend was similar for other two soils. Measurement of bulk density in 0-15 cm depth showed that P1 caused bulk density of silty clay and clay loam soils to decrease 23.8 and 22.8%, respectively; however, it caused the bulk density of loamy soil to increase 4.1%. Bulk density increased with time in all the three soils. Bulk density increased with depth and this increase was higher for lower puddling levels. It seems that higher puddling levels are more suitable for paddy fields preparation because they loose water more slowly. To determine what puddling level is appropriate for different soil textures, parameters such as water infiltration, water retention and amount of water used should be investigated.

In order to analyze the temporal and spatial changes in the amount of water required for puddling in rice fields of the Sapidroud Network, daily soil moisture data from the SMAP satellite was obtained and used in a seven-year period (2015 to 2021). The puddling stage (from April 20 to June 10) was analyzed after grouping based on different probability of occurrence (1%, 10%, 25%, 50%, 75%, 90% and 99%) and using raster calculations. In addition, in order to validate the calculations, the predicted values were compared with the saturated soil moisture values of 321 soil samples with specific geographic coordinates that had been measured by the Rice Research Institute of Iran. The comparison was conducted by using the mean absolute error (MAE), mean bias error (MBE), and normalized root mean square error (NRMSE). The results showed that in all moisture scenarios (from the wettest to driest), the foothills had less moisture than the plain and, especially, the low lands, and the soil moisture showed a decreasing trend during the growing period. The rate of this reduction increased gradually and in some areas it reached 2% per day at the end of the puddling period (May 22 to 31). The amount of gross water required for puddling increased from the wettest to the driest year and in the middle of the season (May 3 to 5) it was from 1693 to 2983 square meters per hectare and at the end of the season from 2496 to 3602 m3/ha, respectively. The validation results showed that the calculated MAE, MBE, and NRMSE values were 4. 26%, 1. 59%, and 15%, respectively, indicating that the accuracy is acceptable. The findings showed that the delay in the start of the puddling operation increases the water required for puddling operation (1. 34 m3/ha for each day delay in a normal year). Therefore, in the lands of this network, in all circumstances, especially in dry years, to save water, it is better to release/supply water required for puddling from local reservoirs, wells, or from the Sepidroud Dam in early May.

Land preparation for rice cultivation especially in the form of paddling could be destructive to soil structure and reduce the yield of crops. This study was conducted to compare the effects of soil puddling, submergence and rice cultivation with normal tillage, nonsubmergence and com cultivation on barley yield as second crop. Also the residual effects of six fertilizer treatments including two levels of organic manure, three applications of urea, and a check were evaluated. The experiment was conducted as split plot in a randomized complete block arrangement with three replications. Rice and com were allocated in the main plots and the fertilizer treatments in subplots. Fertilizers were applied to each plot according to first year randomization and their effects on barley growth, as the second crop, were studied each year and average of three years. Barley seeds of Valfajr variety at 200 kg/ha were sown after rice and com harvest in both plots applying similar tillage system. Analysis of variance revealed a significant difference among fertilizer treatments for seed yield, plant dry weight, number of tillers and plant height. Mean comparison of these traits between the main plots (rice & com) showed higher values for barley planted in com plots. Although not statistically significant, the barley seed yield was about 1 ton/ha higher in com plots. Application of organic fertilizers in the previous crop significantly increased the barley yield, especially in the plots that received the highest quantity of manure. Also split application of urea in three increments in rice and com plots had a significant improvement on barley yield as compared to the treatment that received all urea at once at the beginning of the cropping season.

This research was performed on the basis of a field experiment to evaluate the effects of paddling in machine slipping with three treatments and four replications. In order to determine proper transplanting, the variables such as planting depth, number of pigweeds in hill drop, row distance, hill drop distance, number of total lost hill drops and actual field capacity in one, two, and three times of paddling were measured. The seed of Belpanta variety of rice was for field tillage, the tiller (Kubota-KRA- 75) with 1.35m work width, 7.5 hp was used. The riding type transplanted machine (Yanmar-pr-400) had 4 rows with 30 cm distance between rows. Treatment means were compared by Duncan's multiple range test. The results indicated that the number of puddings increases slipping. There were no significant differences between five and three times of puddings but the difference between three and one times puddings was significant. One time of paddling was regarded the best conditions on the basis of transplanted performance but for weed burial three times of paddling was suggested. More than three times of pudding was not recommended because of technical and economical reasons.

The common method of puddling is using a conventional tiller which requires long time of soil operations.In this study, the effects of tillage equipment on moisture characteristic curve of a paddy soil were investigated. The treatments included tillage equipment (T1: conventional tiller, T2: rotary puddler, T3: cone puddler, T4: tractor mounted rotivator) and number of puddlings (P1: puddling once, P2: puddling twice, P3: three times’puddling and P4: four times’puddling). The results showed that at saturation point, tractor mounted rotivator presented the highest moisture content. At field capacity and permanent wilting point, the cone puddler showed the highest moisture value. The two newly made units held more moisture and saved water. In different tillage equipment, increasing the number of puddling reduced soil moisture. Available moisture in the soil without tillage (control) was less than in soils under rotary puddler and cone puddler.

Due to the importance of rice cultivation, especially in Mazandaran Province, it is necessary to plan carefully for the optimal use of water resources in the province in the agricultural sector, especially rice, to reduce water demand for rice production. For this purpose, an experiment was conducted in the form of a complete block-design with three replications and four treatments using Tarom Hashemi cultivar, during the 2021 crop year in the Rice Research Institute of Iran-Amol. Treatments included conventional planting with flood irrigation (T1) and drip irrigation (T2), transplanting in un-puddled bed with drip irrigation (T3) and direct seed cultivation in dry bed with drip irrigation (T4). The results showed that the cultivation method was effective on yield, plant height, water consumption and irrigation water, water productivity and water use efficiency and was statistically significant at 1% and 5% level of probablity. The highest and lowest yields belonged to T1 and T4 treatments with 4079 and 2876 kg/ha, respectively, and T2 had the highest water productivity with 0. 61 kg/m3, which had no significant difference with T1. The lowest water productivity belonged to T4 with 0. 45 kg/m3. The highest and lowest irrigation water productivity belonged to T2 and T1 with 0. 67 and 0. 52 kg/m3, respectively Based on the results, conventional planting with drip irrigation did not have a significant reduction in yield compared to conventional planting with flood irrigation and increased water productivity by saving water consumption Therefore, the conventional planting method with drip irrigation was recognized as the best treatment in this study.