m.h. biglouei

Many agricultural lands in Guilan province of Iran, especially paddy fields, remain uncultivated in the second half of the year due to various reasons including heavy rainfall, low soil permeability (stickiness of soil particles) and inefficiency of the existing drains. Mole drainage as a low-cost drainage method, proportion for rice cultivation conditions and easier to implement than pipe drainage, can be a suitable solution in the development of second cropping. Due to the oil content of 40% of the seed, the rapeseed plant is one of the valuable oil plants and has the ability to be cultivated as a second crop in paddy fields. Nitrogen plays a key role in the performance of plants and its deficiency causes limitations in plant production. Equipping paddy fields with mole drains along with the application of appropriate level of nitrogen fertilizer can increase the quantitative and qualitative yield of rapeseed as a second crop and contribute to the food security of the country. Therefore, the development of the cultivated area of rapeseed in paddy fields after rice harvesting in Rasht region, the study of the combined effect of mole drainage and different levels of nitrogen fertilizer on yield and yield components were the aims of this project.

In order to investigate the effects of mole drainage and nitrogen fertilizer on the yield and yield components of rapeseed as a second crop in Rasht rice fields, a factorial layout based on a randomized complete block design with three replications at the research field of the Faculty of Agricultural Sciences of Guilan University was implemented in the crop year of 2022-2023. The factors included mole drainage at three levels (without drainage, without gravel and with gravel) as D0, D1 and D2 respectively, and nitrogen fertilizer as urea source at two levels (180 and 240 kg ha-1) as N1 and N2 respectively. Rapeseed plant (Brassica napus) of Delgan cultivar was selected as the second crop after rice harvest. To carry out the experiment, at first the desired land was blocked and divided into plots, then the underground drains of mole were created without gravel and with gravel with a special blade in the desired plots. To drain the drainage from the mole drains, the polyca pipe was installed at the end of each mole tunnel, then the other side of polyca pipe was connected to the sub-pipe collection and finally led to the main surface drain. This experiment was conducted in 18 plots and each one was 9 × 6 meters. The distance between plots was 1.5 m, between replications was two meters, and the distance between plants was 15 and between rows was 25 cm. To avoid the effectiveness of drainage treatments from undrained treatments, undrained plots were considered at the end of the field. Before cultivation, basic chemical fertilizers, 200 kgha-1 of potassium from potassium sulfate source and 200 kgha-1  of phosphorus from ammonium phosphate source were applied. Nitrogen fertilizer from urea source was applied at the level of 180 and 240 kgha-1  in equal amount at three stages. Just before the harvest stage, to determine the traits of the number of seed in the pods of sub-branches, the number of seed per pod, the weight of seed in sub-branches, the weight of seed in the main branch and the weight of seed per plant, ten plants were randomly selected and harvested manually from the crown area. Also, to determine the seed yield, one square meter was randomly selected from each plot, taking into account the borders, and the bushes were manually harvested from the crown area. After the moisture content of the seeds reached the desired level, the seeds were separated from the pods and weighed using a laboratory scale with an accuracy of one thousandth of a gram, and the seed yield was calculated in kgha-1. SOXTEC SYSTEM HT 1043 Extraction Unit set was used to determine oil percentage and Kjeldahl set was used to determine seed protein. Statistical analysis of the data was done using SAS software (version 9.4) and comparison of means was done using the minimum significant difference test at 5% probability level. Excel software was used to draw the graphs.

The results of variance analysis of the data showed that the interaction effects of mole drainage and nitrogen fertilizer on the traits of seed weight in the main branches, seed weight in the plant and seed yield was significant at 5% probability level, so that the highest seed weight in the main branch with 0.733 seeds in the mole drainage with gravel with a nitrogen fertilizer level of 180 kgha-1 (D2×N1) treatment was obtained and the highest seed weight in the plant with 1.443 g in the mole drainage without gravel with a nitrogen fertilizer level of 240 kgha-1 (D1×N2) treatment was obtained. Also, the highest seed yield was obtained under 3579.48 kgha-1 in the treatment of mole drainage without gravel using 240 kgha-1 of fertilizer (D1×N2) which is compared to the treatment of without drainage and drainage with gravel with the same level of fertilizer 13.63 and 2.31 percentage was higher, respectively. In addition, rapeseed plant is more important in terms of oil percentage, no significant difference was observed between drainage and nitrogen fertilizer treatments in terms of average oil percentage. Therefore, the mole drainage treatment without gravel with a fertilizer level of 240 kgha-1 (D1×N2) is the most suitable option for rapeseed cultivation as the second crop after rice harvesting.

The results of this study showed that mole drainage without gravel by improving soil ventilation conditions and preventing waterlogging of paddy fields along with the level of nitrogen fertilizer of 240 kgha-1 increased the yield of rapeseed compared to the condition of without drainage at the same level of nitrogen fertilizer. Therefore, rapeseed cultivation in vast paddy fields after rice harvesting can be recommended as a basic solution in order to increase the production of oilseeds and provide part of the country's oil consumption.

Cultivation of rapeseed as the second crop requires drainage systems in most of the paddy fields of the Guilan province. Mole drainage, as a low-cost and shallow drainage method that is suitable for rice cultivation conditions and easier to implement than pipe drainage, can be a solution in the development of second-crop cultivation. The present study was conducted to evaluate the drainage of mole drainage and nitrogen fertilizer management on the quantity and quality of drainage at Guilan University. In this regard, an experiment was conducted under two treatments including drainage and nitrogen fertilizer (i.e. traditional mole drainage and sand-filled mole drainage), and 180 and 240 kg of nitrogen fertilizer per hectare in three replications. After each rainfall during the plant growth period, water samples were taken from the drains, and parameters of electrical conductivity, pH, total suspended solids, total phosphorus, turbidity, concentrations of ammonium, chloride, nitrite, nitrate, and phosphate were measured. Also, the outflow from the drains and the water table level were measured by piezometers during the rain and after that. The results of the mean comparison of pH and total suspended solids showed that most of them were obtained with 7.49 and 281.25 mg/liter, respectively, in the mole drain filled with sand and the traditional mole drainage and 180 fertilizer treatment. The highest mean of electrical conductivity and turbidity was observed as 651 micro mohs/cm in the traditional mole drainage and 240 fertilizer treatment and with 67.76 NTU in the traditional mole drainage and 180 fertilizer treatment. The statistical analysis showed that the effect of drainage treatment on the amounts of ammonium, nitrite, nitrate, phosphate, and total phosphorus was not significant. The outflow from the traditional mole drainage was 49% lower than the sand-filled mole drainage. The traditional and sand-filled mole drains were able to drain excess water with average reaction coefficients of 0.8 and 0.83 per day during the growth period, respectively. Considering the speed of water discharge, drain discharge, and the main non-significance of qualitative parameters among drainage treatments, mole drainage filled with sand is recommended for the development of rapeseed cultivation in paddy fields.

Chelidonium majus L. has a special place among medicinal plants with its alkaloid and extensive pharmacological properties. To investigate the effects of irrigation interval and ammonium nitrate on some of this medicinal plant properties, a factorial experiment was conducted in a completely randomized design with three replications in the research greenhouse of the Faculty of Agricultural Sciences, the University of Guilan, in 2017. The experimental factors included irrigation interval at three levels of 4 (I1), 8 (I2), and 12 (I3) days and ammonium nitrate at five levels of 0 (N0), 45 (N1), 60 (N2), 75 (N3), and 95 (N4) kg.ha-1. The ANOVA results showed that the interaction of irrigation interval and nitrogen fertilizer was significant on root fresh weight, fresh and aerial parts dry weight, total dry weight, and root volume at 5% probability level and root dry weight, total fresh weight, and alkaloid content of roots or aerial parts at 1% probability level. The highest root fresh weight (68.92 g.plant-1) was obtained in the I2N0 treatment. Also, the highest aerial parts fresh weight (33.54 g.plant-1) and total plant fresh weight (92.92 g.plant-1) were observed in the I2N4 treatment. The highest root (1.72 mg.g-1 DW) and aerial parts (1.23 mg.g-1 DW) alkaloid content was obtained in the I3N1 and I2N0 treatments, respectively. Overall, the 8-day irrigation interval with increasing the fertilizer amount and 12-day irrigation interval with less fertilizer amount (0-60 kg.ha-1) treatments could be recommended in the production of Ch. majus under greenhouse cultivation, respectively in terms of yield and different parts alkaloid content.

In order to evaluate soil water content and water uptake by corn plant roots (Single cross 260) under different soil moisture and water salinity stresses using the agro-hydrological Soil–Water–Atmosphere–Plant (SWAP) model, an experiment was conducted in 2015 at the green house of the Agriculture Research Center of Shahrood, Iran. The statistical model employed was a split plot based on a randomized complete block design with three replications. The main plots consisted of three levels of irrigation; 50 (I1) (full irrigation as the control), 75 (I2) and 100% (I3) of Total Available Water (TAW) depletion while the sub-plots consisted of three levels of salinity of irrigation water; 2 (S1), 4 (S2) and 6 (S3) ds.m-1. The results showed a good correspondence between the simulated soil moisture, water uptake and measured values. The normalized root mean square error (nRMSE) and the root mean square error (RMSE) values of the predicted soil moisture were 4.58 and 24.96 and for the water uptake by the roots were 23.37 and 35.48, respectively. The R2 of coefficient of simulation for water uptake by roots in different treatments were 0.38 to 0.8. The dataset of the predicted and measured values were close to the 1:1 scale line for both soil moisture and water uptake. This study indicated that the SWAP model can be used as a powerful tool to simulate field water cycle and evaluate irrigation practices. Accordingly, taking into account the existing conditions of the region such as weather and soil type and preparing scenarios based on possible management options, management strategies can be optimized according to the results achieved for the SWAP model simulation.

Rice-duck cultivation is an integrated farming technology, which could increase rice production, grain quality and ecological sustainability in paddy fields. One of the main strategies in sustainable agriculture is the use of optimal cultivation systems in agricultural systems which could be increased the range of adaptation of rice to flooding depth and degree of moisture control. Rice-duck cultivation could be affective to weed control as well as reducing environmental pollution which caused by herbicides and providing the development of environmentally friendly agriculture. It should be noted that traditional and conventional cultivation systems have been faced with problems such as permanent flooding of paddy fields, soil erosion, resistance to pests and pathogens and weeds to chemical pesticides, and environmental pollution. Moreover, they require a lot of labor and water, and high energy, which has increased the need to pay attention to new approach. Studies have showed that the application of effective methods in water productivity, including SRI due to improved irrigation management in the field in terms decreased drainage water, permeability and the consequences of conventional cultivation and increasing soil fertility (duck) can significantly increase the water productivity. The aim of this study was to investigate the effect of duck application and weed control in different planting systems on yield and abundance of dominant weeds under field conditions.

The experiment was conducted as a split plot factorial in a randomized complete block design with three replications during two years of 2017-2018 and 2018-2019 at Guilan University. Treatments included three different cultivation systems (conventional, improved, and SRI) as the main factor, and factorial combination of two duck density (un-use and 750 No ha-1) and three weed control (control (un-weed control), once and twice of weed control) as the sub factor. The experiment had three replications and the length of each plot was 4.5 meters and the width was 4 meters. In order to carry out the experiment, first plowing in the land to a depth of 20 to 25 cm with a rotator and paddling with a tiller was done according to the custom of the farmers of the region. In all plots, 80% of the recommended fertilizer was applied in SRI system after deducting the values of cow.

The results showed that abundance and dry biomass of weeds (Umbrella sedge, Barnyard grass, Knot weed and Arrow leaf) were significant in terms of planting system. In all planting systems, 750 ducks ha-1, once and twice weed control, caused complete loss of ovaries, Umbrella sedge, Barnyard grass, Knot weed, and Arrow leaf due to ducks' non-use conditions. 750 ducks ha-1 compared to un-use duck in conventional, improved and SRI planting systems increased grain yield of 21.61, 20.80 and 30.84%, respectively. Also, the application of 750 ducks ha-1 in compared to the conditions of un-used of duck in the cultivation systems of conventional, improved and SRI, increased by 34.80, 33.01, and 38.69% of water productivity, respectively, while there was no significant difference between different levels of weed control in the 750 ducks ha-1 in terms of water productivity.

In general, duck increased plant growth, improved power of rice and finally increased rice yield by proper weed control in the field with muddy water and beak, as well as adding rubbish to the paddy field. According to the results of this study, probably do once the initial hand weeding to control dominant weeds in SRI rice cultivation system with 750 ducks ha-1 to improve rice production systems and to increase water productivity in fields of Guilan province is appropriate.

The aim of this study was to compare the linear regression and neural networks methods in estimation of the wetting dimensions in the drip irrigation systems on sloping lands. Experiments were performed with a constant flow rate of 4 L.hr-1 with five irrigation duration times of 4, 6, 8, 10 and 12 hours on the lands with sloping of 0, 5, 15 and 25 percent on a silty loam soil in Moghan Fathali plain region at four replications. The Results of the estimation of the wetting front depth by means of statistical indices of R2, EF and RMSE, using multi-layer perceptron neural networks were 0.98 and 0.98 and 1.07 cm, respectively and using multiple linear regression method were 0.93 and 0.93 and 2.1 cm, respectively. The comparison results of these mentioned methods for estimating area of wetted soil profile using statistical indices of R2, EF and RMSE, were 0.99, 0.99 and 22.16 cm2, also 0.93, 0.93 and 74.77 cm2, respectively. So, the multi-layer perceptron neural network was more suitable for the estimation depth of the wetting front and area of wetted soil profile than the multiple linear regression method. However, Results of comparison between multi-layer perceptron neural networks and multiple linear regression methods for the estimation of the wetted soil surface area using statistical indices of R2, EF and RMSE, were 0.99, 0.99 and 18.22 cm2, also 0.90, 0.90 and 126.44 cm2 respectively, showed that the multiple linear regression was more appropriate than the multi-layer perceptron neural networks.

To investigate the effect of deficit irrigation on quantitative and qualitative yield of soybean cultivars, an experiment was conducted as split plots based on randomized complete block design with three replications at agricultural research farm, university of Guilan, during 2009. Main factors were included four irrigation levels based on potential moisture 30-35 (I1), 50-55 (I2), 70-75 (I3) Centibar (irrigation time was determined by tensiometer) and without irrigation (I4), and sub plot factors were included seven soybean cultivars: 033, 032, Sahar (group maturity 4), L.17, Zan, Clark and Madari (group maturity 3). Results showed that seed yield of soybean had decreased in I2 I3 and I4 treatments (15%, 20% and 65% respectively). Among the studied traits, just oil and protein content have increased by drought stress. Highest (1379 Kg) and lowest (478 Kg) seed yield per unit area obtain from I1 and I4, respectively. 033 in I3 treatmenthad the highest and Zan in I4 had the lowest oil and protein yield. Also irrigation water productivity increased significantly with application of deficit irrigation treatments (13% and 33% increment in I2 and I3, respectively). Results of the present experiment showed that in soybean production in Rasht region, irrigation based on potential moisture 70-75 Centibar, moreover in economize of water use and increase in water productivity, can improve of soybean seed oil and protein percentage.

In order to evaluate the effects of deficit irrigation on yield and water productivity of seven soybean cultivars, an experiment was conducted as split plots based on randomized complete block design with three replications at agricultural research farm, Faculty of Agriculture, Guilan University. Main factors of the experiment were four irrigation levels based on soil moisture potential, 30-35 (I1, full irrigation), 50-55 (I2), 70-75 (I3) centibars (measured using tensiometer) and without irrigation (I4). Sub plot factors were included seven soybean cultivars: 033, 032, Sahar (maturity group IV), L.17, Zan, Clark and Madari (maturity group III). Water productivity was calculated based on seed and biological yield. The results showed that deficit irrigation significantly reduced seed yield. The highest and lowest values of the seed yield were obtained in I1 and I4, respectively. But irrigation water productivity significantly increased with application of deficit irrigation treatments (13% and 33% increment in I2 and I3, respectively). During the growing season, treatment I1 received the highest amount of irrigation (2457.14 m3/ha) and also the highest frequency of irrigations (8). According to the ratio of dry matter production to water consumption, water productivity of this treatment (I1) was low. Among all of the irrigation treatments, I3 showed the highest water productivity and there was no significant difference between I2 and I3 for the seed yield. It seemed that I3 had the best water productivity index. Among the studied cultivars, cultivar 033 showed the highest irrigation water productivity (this cultivar had the highest seed yield, as well). According to the results of the present experiment, in Rasht region, combination of treatment I3 and cultivar 033, not only economizes water consumption, increases irrigation efficiency and optimum use of water resources but also produces satisfactory soybean seed yield.