جستجوی مقالات مرتبط با کلیدواژه "rice yield" در نشریات گروه "آب و خاک"

Simultaneous improvement of water and nitrogen use efficiency in paddy fields is necessary to reduce the environmental- related issues. Rice, as one of the most important crop, provides the main food of more than half of the world's population. According to the latest available statistics, in the crop year 1396-97, the rice cultivated area the country was 622991 ha, which mainly belongd to the five provinces of Gilan (35.3%), Mazandaran (34.3%), Khuzestan (10.9%), Golestan (9.9%) and Fars (3.4%). Among different provinces, Mazandaran province is the main producer of rice in the country with the production of 1113715 tons of rice. Additionally, rice is the predominant crop in Mazandaran province.

The required field data of Daylamani rice cultivar were obtained during two rice growing seasons (2011-2012) from one ha consolidated paddy field in Sari, Mazandaran province. Data from 2011 were used for calibration and data from 2012 were used for validation of the CERES-Rice model of DSSAT V4.7.5 software package. By using the validated model, the effect of different scenarios of water and nitrogen fertilizer management on water use efficiency (WUE), economic water use efficiency (EWP), physiological efficiency of nitrogen consumption for grain production (NUEg), harvest index and nitrogen harvest index (NHI) were evaluated. The calibrated model was then applied to evaluate the combined effect of three types of irrigation management including continuous flooding (I1), intermittent irrigation with 5 (I2) and 8 (I3) days irrigation frequency and six N fertilizer management treatments including N1 (50% at planting (P), 25% at tillering (T) and 25% at clustering (C)), N2 (25% at P, 50% at T and 25% C), N3 (25% at P, 25% C and 50% at T), N4 (fertilization at C), N5 (fertilization at T) and N6 (fertilization at P).

The minimum (832 kg/ha) and maximum (3640 kg/ha) grain yield were obtained in I1N6 and I3N5, respectively. The simulations showed that the effect of fertilization time and type of irrigation were not independent of each other. I3N5 resulted in maximum HI (0.39), minimum soil evaporation (173.4 mm), maximum WUE (one kg/m3), maximum EWP (12×104 Rials/m3), minimum nitrate losses (52.47 kg/ha), the highest nitrogen fertilizer uptake (99 kg/ha), maximum NUEg (one) and minimum nitrogen stress (0.05). Also, the maximum NHI (0.37) belonged to the I2N5 treatment.

Based on the results, among the applied managements, according to the components of crop yield, harvest index, water productivity, EWP, NUEg, nitrogen uptake, nitrate leaching and NHI, 8 days irrigation frequency was the best option in terms of irrigation management. Also, the use of I3N5 treatment as a superior combined- treatment under both fertilizer and irrigation management in the present study is recommended in terms of water and N use efficiency in the paddy fields of the province.

Meeting the demand for rice in the country as a strategic product is of special importance. The objective of this study was to investigate the effect of soil properties on rice yield and their rating to prepare a table of soil and landscape requirements of this crop for use in land suitability assessment studies. For this purpose, 99 rice fields in Mazandaran, Guilan, and Khuzestan provinces were selected. In each farm, a soil profile was studied and a land use questionnaire was completed. After the necessary physical and chemical analyses, a simultaneous multivariate regression between yield and different soil properties was investigated. Then, in order to prepare a table of soil and landscape requirements for rice, simple regression relationships between effective soil characteristics and yield were investigated and rated for different land suitability classes. Verification of the proposed table was performed using data from 18 rice fields (about 18% of the whole data). The results showed that the range of yield, lime, sand, clay and silt in selected fields was extensive, but the percentage of exchangeable sodium and soil salinity were in a more limited range. In multivariate regression, the variables of salinity, ESP, lime, soil reaction, percentage of clay and sand, respectively, were efficient. The coefficient of determination of the proposed equation was about 0.38. Also, the value of the coefficient of determination between yield and soil index for verification data was about 0.71, which indicates the reliability of the proposed table in this study.

Due to the increasing environmental and economic costs associated with nitrogen (N) consumption, improving N use efficiency in rice cultivation systems is of great importance. In this regard, the combined effect of different surface and subsurface drainage systems and water management on the nitrogen harvest index (NHI) of rice was investigated. During three rice growing seasons (2014 to 2016), two rice varieties of Tarom Hashemi and Tarom Daylmani were cultivated under alternate wetting and drying in paddy fields with surface and subsurface drainage systems. At harvest, grain yield and biomass and plant and seed nitrogen were measured. The NHI was determined as the ratio of grain nitrogen to nitrogen absorbed by aboveground part of plant. The amount of NHI was directly related to the amount of urea fertilizer used, varying between 58.31 and 68.45 in different seasons. The average nitrogen absorbed by the Hashemi and Daylmani plants in the subsurface drainage systems was 161.7 and 155.7 kg ha-1, respectively, and in the control was 144.7 and 193.7 kg ha-1, respectively. Also, the average grain yield, grain nitrogen, harvest index and NHI in the subsurface drainage systems were 5329.3 kg ha-1, 105.9 kg ha-1, 37.8% and 67.2%, respectively, and in the control treatment was 4667.7 kg ha-1, 88.6 kg ha-1, 32.4% and 56.3%, respectively. Based on the results, drainage through subsurface drainage systems under intermittent irrigation and drainage management can improve the N use efficiency in rice cropping system

Population growth, climate change and improper management, have caused a water shortage crisis in the world and especially in Iran. So it is necessary to change attitudes in irrigation management from the emphasis on production per unit area to maximize production per unit of water consumption. The aim of this study was to investigate and evaluate the effect of localized irrigation tape (TIP) on water productivity (CPD) and water economic productivity (NBPD) in paddy fields. The experiment was carried out as a split plot design with three replications in 2019-2020 crop year. In this experiment, the main factor was irrigation method including flood irrigation (FI) and three levels of deficit irrigation; 25, 50 and 100 cm tape space (TP25, TP50, TP100) and the sub-factor was two rice cultivars; Amir and Fajr. Results showed that the highest values ​​of CPD of water consumption and water delivery and NBPD were corresponded to TP25 irrigation treatment for both cultivars. The highest CPD of water consumption was 0.66 and 0.94 kg/m3 in Amir and Fajr cultivars, respectively, and the highest CPD of irrigation water was 0.74 and 1.07 kg/m3 in Amir and Fajr cultivars, respectively. Also, the highest NBPD in Amir and Fajr cultivars were 32107 and 40852 Rials per cubic meter, respectively. The TP25 irrigation treatment increased NBPD in Amir and Fajr cultivars 36 and 63%, respectively. Also, in average about 4500 cubic meters per hectare of water will be saved annually. Therefore, this irrigation treatment increases water productivity of water consumption and water delivery and also economic benefits in both cultivars.

Although there are numerous studies on the effect of soil and foliar application of Zn on rice yield, knowledge on Zn distribution in rice tissues through simultaneous soil and foliar application of Zn is limited. Therefore, The current experiment was conducted to explore the effect of soil and foliar application of zinc sulfate fertilizer on Zn and protein content of grain, and Zn content of rice (Oryza Sativa L.) tissues at different growth stages of Hashemi local cultivar. This filed experiment was carried out on two factors (soil application of Zn at three levels and foliar application of Zn at four levels) using complete randomized block design with three replications. The maximum grain yield (4283 kg ha-1) was recorded at simultaneous application of 20 kg Zn ha-1 (basal soil application) with foliar application of Zn solution at ripening stage, giving 32% increase compared to the control (2915 kgha-1). The highest increase in leaves and stems Zn content (2 times) was recorded at the combined treatments (10 kg Zn ha-1 and foliar spray at the maximum tillering stage). Also, the maximum increase in panicle and rice grain Zn (around 2.5 times) was obtained by application of 10 kg Zn ha-1 and foliar spray at the flowering stage. The highest linear correlation coefficient was found between grain and panicle Zn content (0.58**). Meanwhile, the grain protein content positively correlated with grain Zn content (0.68**), panicle Zn content (0.64**) and Zn content of stem (0.64**). Among the aerial parts, the highest linear correlation coefficient was found between Zn content of panicle and leaves at ripening stage (0.69**), Zn content of leaves and stems at flowering stage (0.65**), Zn content of stems at ripening stage and root Zn content at flowering stage (0.45**). The fitted stepwise multiple regression analysis  among protein content of rice grains and Zn content of all rice tissues at different rice growth stages indicated that grain Zn content, Zn content of leaves and stems at ripening stage had positive significant relationship with protein content of grains. According to adjusted coefficient of determination, these characters demonstrated 56% of protein content variations. It can be concluded that soil application of 20 kg Zn ha-1 in combination with Zn foliar application of  0.5% Zn sulfate at flowering stage of rice plant enhance grain yield and quality.

Due to limited water resources in the country, the use of new methods of irrigation with low water consumption seems necessary. Subsurface irrigation is one of the few methods to increase crop water productivity. Also, in order to cope with the water crisis, unconventional water can be used, in other words, poor water quality is being applied. There are several methods for improving the quality of water in the agriculture section, one of which is the use of magnetic fields. The purpose of this study was to investigate the effect of groundwater table management on reducing water consumption and to investigate the possibility of sub-irrigation (drainage controlled) with magnetized wastewater of Gorgan urban refinery on rice yield.

This study was conducted from May to September of 2018 in Gorgan Agricultural and Natural Resources University. The experiments were carried out in a lysimeter with a diameter of 30cm and a height of 50cm. The experiment was conducted as a factorial based on randomized complete block design with three replications. Treatments included water type factor (ordinary water (C) and sewage (W)) and water correction factor (magnetic (M) and non-magnetic (O)). To control the water level, two water tanks were used, one as a stabilizer water table and another to measure the amount of water used. Part of the ordinary water and wastewater was magnetized using a DC magnetic field generator with magnetic one tesla field intensity. Underground irrigation was then carried out on the soil columns in which the rice plant was cultivated so that the water table depth was fixed at 5 cm from the soil surface. The lysimeters were irrigated with ordinary water for one week, in the second week of treatments were applied. At the end of the growing season, traits such as rice husk yield, biological yield, harvest index, water use efficiency, physical water productivity and economic water productivity were determined. The measured data were analyzed using SPSS. Also, comparisons of means were performed by using the t-test and Duncan tests at 5% level of probability.

The results of the comparison mean water type factor showed that there was no significant difference between the wastewater and the normal water in the parameters of the measurements. Correction Water showed that non-magnetic water was significant in rough rice yield, water use efficiency, water physical productivity, and water economic efficiency compared to magnetite, but on biological yield and harvest index had not a meaningful effect. Also, the comparison of the mean of water type and correction water method on all measured parameters indicated that the nonmagnetic wastewater was superior to the rest of the treatments at the 5% level.

This study was conducted to investigate and further study two methods of controlled drainage management and underground irrigation for rice cultivation with the Gorgan municipal wastewater treatment plant. Based on the results of the comparison of mean interaction effects of treatment compounds, non-magnetic effluent was identified as the best treatment composition in this experiment. According to the results of this research, we can say:  Rice cultivation in terms of irrigation does not require the formation of a standing water layer on the surface of the soil. Also, by using wastewater of Gorgan urban refinery for irrigation water, in addition to reducing the harvesting of high-quality water resources, the cost of fertilizer use (chemical and organic) in the production of crops can be reduced. Overall, the results of this study showed that the magnetic factor had no effect on the improvement of rough rice yield, water use efficiency, physical productivity water and economic efficiency of water under underground irrigation conditions. However, it should be noted that the results of this research are only It is obtained by a magnetic device model. Therefore, it is possible that the use of different models of magnetic devices results in different results. It is also probable that the passage of irrigation water with different compositions (percentage of cations and various anions) from the magnetometer can lead to different results on other crops or cultivars of a crop.

Rice is one of the strategic agricultural crops in Iran and provides a high percentage of dietary calorie and protein of the people. With a rapidly increasing population and the consequent increase in food demands, it is necessary to know the relationship between rice yield and soil conditions. Therefore, the objective of the present study was to evaluate the relationships between yield and soil quality (SQ) in order to provide guidance regarding proper soil management practices for the sustainable development of Goldasht region paddy fields, in Mazandaran province. One hundred and twenty-eight surface soil samples were collected to measure some physical and chemical soil properties. At harvest time, grain yield was measured at 14% moisture content. Firstly, to determine the SQI, the characteristics with the highest effect on the SQI of the region were identified by the Principal Component Analysis. Fuzzy logic method was used to convert quantitative soil properties to qualitative ranking and, finally, the indices were combined using the concept of coefficient of variation. The average recorded rice grain yield of the studied area was 3498 kg ha-1 and SQI varied between 0.47 and 0.97. Contrary to expectation, there was no significant correlation between performance and SQI in the studied area (reasons are explained in discussion section). According to the results of SQI classification, available phosphorous is the most important limiting factor for soil quality in the area. Direct comparison among maps of yield and soil quality indices indicate that proper soil conditions along with proper management of the farm can be an effective solution to maximize rice yield. Thus, proper management by the farmers can remedy shortcomings and somewhat inappropriate soil conditions. However, in many cases, proper soil quality alone cannot compensate for crop management shortcomings.

Assessing soil quality and balancing between crop production and quality of natural resources are essential issues in sustainable soil management for agricultural and natural resource protection. In agricultural fields for optimum management and maximum economic productivity, knowledge of the factors affecting the soil quality is necessary. Also, determining the appropriate method for soil quality evaluation is important for sustainable soil management and soil degradation prediction. This study was carried out with the aim of assessing soil quality of paddy fields, determining the minimum data set for soil quality evaluation and investigating the effect of soil quality index using different methods on rice yield in Pirbazar region of Guilan province. Based on the mean annual rice yield, the selected paddy fields were divided into low (4.6 t ha-1) productivity. Sixty soil samples were collected from 0 to 30 cm depth. The rice products were harvested at a 1 m2 plot at each site. In this research, using the principal component analysis (PCA) method, among 20 physical, chemical and biological soil indicators as total data set (TDS), 6 indicators were selected for the minimum data set (MDS). Then, the soil quality of high and low productivity paddy fields was evaluated by simple additive integrated quality index (IQISA) and weighted additive integrated quality index (IQIWA) in two collections of soil properties include MDS and TDS. To evaluate soil quality of paddy fields, an MDS was established with organic carbon, total nitrogen, available potassium, clay percentage and urease activity and these explained about 67% of the soil quality variability. The significant differences were found between the soil quality index of low and high productivity paddy fields when IQIWA and IQISA were developed based on MDS. So that, the mean IQISA-MDS and IQIWA-MDS of the high productivity paddy fields (0.84 and 0.89, respectively) were higher than low productivity paddy fields (respectively 0.78 and 0.80, respectively). Additionally, data indicated that IQISA-MDS and IQIWA-MDS were most strongly correlated with crop yield, the correlation coefficient ranged between 0.44–0.54. Significant differences between the soil quality indices based on MDS for low and high productivity paddy fields indicated that the MDS more efficiently shows the difference of soil quality between paddy fields with different productivity. The significant correlation between IQISA-MDS and IQIWA-MDS indices with rice yield indicated that an MDS with a limited number of indicators was carefully selected and effectively evaluated the status of soils as a rice production medium. Therefore, using an MDS can save time and money and assess the reliable soil quality indices of paddy fields in the study area.

Multi-variate statistical methods such as principal component analysis (PCA) and regressions could be used to facilitate the interpretation of complex relationships. The objective of this study was to determine the most important soil fertility properties affecting rice yield in the paddy fields. For this purpose, soil samples were taken from the plow layers of 119 points with suitable distribution in the paddy fileds located in Shaft and Fouman cities of Guilan province. Then after, physical and chemical properties of the soil fertility were measured and analysed using descriptive statistics, principal component analysis and regression methods. Results showed that three PCs with eigen values greater than one named as “k and it’s preservation factors”, ”Total N and it’s provider factors” and ”P and Thickness of plow layer” are respectively explained more than 67.4% of the variability in the soil physical and chemical properties and 55% of the yield variability. In addition, the corresponded properties to the PCs explained 80% of the yield variability. Consequently, in order to increase the yield, management practices such as proper fertilizer applications of nitrogen, potassium and phosphorous and proper tillage for creating suitable plow layer are recommended.

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The problem of soil salinity exists in the paddy field areas in Iran, especially in the Caspian Sea coastal areas, due to its proximity to the sea and low altitude with saline and shallow water table. Besides, considering that rice is one of the most important strategic crops for economy of Iran and the people in this area, this research was necessary in order to investigate the possibility of production of rice in the presence of shallow and saline groundwater table. This research was performed as a physical model (insulated metallic lysimeter) in the Meteorological Research Center of College of Agriculture and Natural Resources, University of Tehran, in 2017. The complete randomized design included two treatments with shallow water table: FSG and SSG, with fresh (control) and saline water, respectively. The salinity of irrigation water was 0.94 dS/m for both treatments. Moreover, for SSG treatment, the EC of shallow groundwater was 20 dS/m at 40 cm soil depth and was regulated as an artificial recharge. The results of salinity profile in SSG treatment showed that there was almost no mixing of fresh and saline water in interstitial zone (under the hard pan from 30 cm to 40 cm of soil surface). In this manner, there was insignificant effect of salinity in the root zone, because of existing of permanent water layer in rice field and downward water flow, which makes an obstacle for upward flow for saline water. This problem did not affect the rice yield, which didn’t decrease. The results of data analysis confirm this and show that shallow groundwater salinity has no significant effect on the parameters like leaf area index (LAI), root length (RL), plant length (PL), membrane stability index (MSI), chlorophyll (SPAD), relative water content (RWC) and the biomass (BIO). The difference between the performance of the control and the salinity treatments was about 1 to 12 percent, while the grain and biological yield in SSG treatment compared with FSG treatment decreased 3.2% and 4.5 percent, respectively. Therefore, considering the significant leaching of soil after cultivation, the negligible loss of yield and upward movement of saline water in the soil, production of rice and other plants in such areas seems possible. Also, with the help of efficient and effective use of lands with shallow saline groundwater, we can decrease the pressure on conventional soil and water resources.

Soil quality shows permanent ability of soil as a vital system as alive vital system in ecosystem under different utilizations. In this regard, indicators of soil quality as evaluation and decision-making criteria are used. This study conducted to investigate the effect of remaining fertilizer on chemical properties of soil in faba bean- rice cropping system including first cultivation, rice and second cultivation, faba bean by 15 fertilizer treatments for faba bean in the form of a factorial randomized complete block design with three replications in the field of Rice Research Institute of Iran for years 2012- 2015 (Including two periods of cultivation for rice and three periods of cultivation for faba bean). Experimental factors for faba bean comprised five nitrogen rates (0, 25, 50, 75 and 100 kg N. ha-1) from urea and three phosphorus levels (0, 50 and 100 kg P. ha-1) from triple superphosphate fertilizer. Results showed that increasing nitrogen rates reduced soil acidity and electrical conductivity increased. Also faba bean cultivation led to increase in organic carbon percentage (% 2.81), N (% 0.209), P (40.59 ppm) and K (237.69 ppm).The highest soil phosphorus was observed in P100 (42.69 ppm) in rice cultivation. The average yield of two- cycle production of rice was about 2770.95 kg. ha-1.

In order to study the effects of rate and time of nitrogen application on vegetative characters, i.e., yield and yield components of rice (Zayandeh-rood variety), an experiment was conducted at Isfahan University of Technology research farm during summer 1996. Four N rates including (60, 90, 120 and 150 KgN/ha) and four splitting form (1- all N applied before transplanting 2- 1/3 N applied before transplanting, 1/3 at the beginning of tillering and 1/3 at the emergence of first panicle in 50% hills 3- 1/2 at the beginning of tillering and 1/2 at the emergence of first panicle in 50% hills 4- 1/3 at the beginning of tillering and 2/3 at the emergence of first panicle in 50% hills) were evaluated in a factorial experiment which was arranged in a randomized complete block design with 3 replications. Plant height, number of tillers per unit area and days to heading and maturity increased with an increase in the rate of fertilizer application. Grain yield and number of panicles per square meter increased when the N rate was raised to 120 Kg N/ha, while application of 150 Kg N/ha resulted in the reduction of grain yield and number of panicles. Nitrogen rate increases did not have any significant effect on number of grains per panicle. The grain weight did not follow any particular trend at different application rates, but harvest index and percentage of filled grains were decreased as the N rate increased. The percentage of nitrogen content of plant was increased as a result of higher N - rate at heading and harvest times. Treatments containing base application of nitrogen resulted in an increase in plant height, number of tillers, plant dry matter, grain yield and number of panicles per square meter, although it caused a reduction in harvest index. The number of grains per panicle and grain weight did not follow any particular trend under the influence of time of application, although plant nitrogen content increased with a delay in time of fertilizer application.