جستجوی مقالات مرتبط با کلیدواژه "چغندر قند" در نشریات گروه "آب و خاک"

Climate change is an undeniable phenomenon, which affects virtually every aspect of life on Earth. The agricultural sector is heavily connected to the environment and thus, gets affect by climate change the most. Climate change affects agriculture by affecting temperature and rainfall. The elevated air temperature increases the potential evapotranspiration. Variation in precipitation is generally unfavorable. Increase in precipitation causes waterlogging and subsequently erosion in soil, while decreased precipitation causes water stress in crops. It is necessary to assess the climate change impact on agriculture in order to change policies accordingly. This paper sought to assess the impact of climate change on sugar beet net irrigation water requirement and potential yield. In this research, the climatic information of the meteorological station located in Mohammadshahr, Karaj for the period 1970-2014 and the crop parameter of the sugar beet research farm located in Mehrshahr, Karaj were used. Future climatic data from six global climate models, namely ACCESS-ESM1-5, CanESM5, EC-EARTH3, IPSL-CM6A-LR, MRI-ESM2-0 and NorESM2-LM, under three optimistic, intermediate and pessimistic scenarios (SSP126, SSP245 and SSP585) for the period 2015-2100 were downscaled for Karaj using empirical quantile mapping method. Taylor diagram was used to evaluate the downscaling results. Temperature and precipitation data as well as reference evapotranspiration, which was calculated by Hargreaves-Samani method, were given to AquaCrop model. The effective rainfall calculation approach was set to USDA-SCS method in AquaCrop model. The trend and fluctuations of the climatic and crop variables were examined using the Mann-Kendall and Pettitt tests, respectively.The results indicate that the sugar beet sowing and harvest dates advance by 39 and 71 days, respectively, which means a decrease of 29 days in the growing season length (from 171 to 142 days). The reference evapotranspiration under SSP585 will increase by 14.8% (6.5% under SSP126) at the end of the 21st century in Karaj. The water requirement can increase up to 7.8% under SSP585 (3.7% under SSP126). The amount of irrigation water requirement in the future period will increase up to 10.5% under SSP585 (5.8% under SSP126). The biomass and yield variations at the 21st century ending period will be 11.8% and 19.2% increase under SSP585 (4.2% and 5.9% increase under SSP126), respectively. All the climatic and crop variables showed strongly significant trend in the study period (1995-2100) under the pessimistic scenario, while the fluctuations of the variables were not as significant as their corresponding trends under the same scenario.According to the results of this paper, the increasing temperature caused by the elevating atmospheric CO2 concentration, under the pessimistic scenario, increases the sugar beet net irrigation water requirement by increasing the crop evapotranspiration. The decreasing precipitation also contributes to the obtained result. The potential yield showed a contradicting result, i.e., the elevated CO2 under the pessimistic scenario favors the yield production due to the fact that more CO2 contributes to more efficient photosynthesis. The results can be used in climate change adaptation policies regarding water allocation and optimal planting date determination for sugar beet cultivation in Karaj.

For optimization autumn sugarbeet irrigation water, an experiment was conducted at Safi-Abad Agricultural Research center in the years 2010 and 2011 with silty clay loam soil.The experiment was arranged in randomized complete blocks design with three replications. Tape irrigation levels (25,50,75,100 and 125% of water requirement with T25,T50,T75,T100 and T125 respectively) and furrow irrigation was conducted. Production, cost and water function and thresholds indexes basis of irrigation depth was compared and computed. Although full rrigation in field experiment(T100 treatment) and maximizing level of applied water index(Wm) had maximum yield, T100 treatment had not significant difference with T75 and T50 treatments. On the other hand irrigation water application depth in water limited condition (Ww) was almost equal to minimum rate of water application,T25 treatment. Although Ww index had not maximum net benefit per unit of irrigation water, caused to decrease 43 percent consumed water and 21 percent of root yield and caused to increase sugare content and decrease irrigation costs. The results showed that in a view economic deficit irrigation in North of Khouzestan climatic conditions was applicable.

In order to evaluate the effect of urban wastewater and different fertilizer sources on macro and micro nutrient's concentration and shoot dry weight of sugar beet, a field experiment was arranged as a split plot in RCBD design with three replications at Research Station of Shahrekord University in 2013. The main factors included irrigation with urban wastewater at 2-4 leaf stage and 8-12 leaf stage, and irrigation with normal water (control). The four types of fertilizer included sheep manure, spent mushroom compost, chemical fertilizer and no fertilizer (control) in the sub-plot. The results showed that the plot irrigated with urban wastewater at 8-12 leaf stage significantly increased leaf number and shoot dry weight of sugar beet compared to the plot irrigated with tap water. Besides, the plot irrigated with urban wastewater at 8-12 leaf stage had a significant effect on the elements of N, P and K concentration in shoot dry weight of sugar beet, but the plot irrigated with urban wastewater did not significantly affect the elements of Fe and Zn concentration. From among the fertilizer treatments, the maximum shoot dry weight and leaf number per plant belonged to the application of sheep manure and also the highest elements of Fe and Zn concentrations belonged to the treatment of spent mushroom compost.

In order to evaluate the influence of different irrigation systems on lateral movement of urea fertilizer and its effect on nitrogen-15 microplot design, an experiment was carried out during 2005-2006 in a randomized complete block (RCB) design (split plot) on lettuce and sugar beet with three treatments and replications. The plot area was 144 m2 and in the middle of each plot, an area about 1 to 3 m2 was selected as an isotopic subplot. The treatments were different irrigation systems (main factor) consisted of trickle fertigation (T1), sprinkler fertigation (T2), and furrow irrigation (T3) and different plant sampling areas (sub factor) consist of central part, first and second guard and non isotopic area. The crops were harvested in different parts of microplots and 15N/14N isotopic ratio was determined by the means of emission spectrometer NOI7. The results showed that, in lettuce culture, central parts of isotopic subplots and first guards were in the same statistical groups and 48% of fertilizers were supplied with the labeled materials. For sugar beet cultivation, central parts of isotopic subplots, first guards and non isotopic parts were situated in three different statistical groups and decreasing slope of nutrient absorption were 31% and 82% respectively. Therefore, for suitable design of isotopic subplots, increasing fertilizer use efficiency is quite necessary and by means of this methodology, low enriched fertilizers can be applied through the field experiment. It is also important to leave one row of plants (as guard) between isotopic and non isotopic rows to prevent lateral movement of nitrogen fertilizer. In this condition, area of isotopic subplots can be shrinked up to 0.56 m2 (in lettuce) and 1.12 m2 (in sugar beet). Under this condition, the efficiency of system can be increased up to the level of plastic barrier isotopic subplots. On the other hands, in furrow treatment, by presence of active rooting system (in accordance with absorption of nitrogen), liner movement of nitrogen were adjusted (along with irrigation channel), and this is the main reasons for similarity of system with drip and sprinkler fertigation methods. In the furrow irrigation system, movements of nitrogen-15 were more complicated. Therefore, the best place of sampling is 25 cm ahead of irrigation water pathway.

Tissue nutrient status of high yielding plant populations can be a reference norm for evaluation of growth and achievement of optimal yield. Compositional reference norms derived from generic models are important. Yield data of 382 sugar beet fields was analyzed and, using mathematical approach, cumulative variance ratio function, and chi-squared distribution function, the low (n1= 259) and high (n2= 123) yielding subpopulations were separated from each other. Cutoff yield was obtained at 53.980 t.ha-1. Critical chi-squared value was found to be 7.3 and was confirmed by using data of leaf samples from 38 fields and Cate-Nelson statistical procedure. Preliminary CND norms of different elements were found as follows:, ,, ,, ,, ,. Later, nutrient sufficiency range and critical intervals norms and nutrient indexes for CND were determined using analysis results of 38 sugar beet tissue samples. Satisfactory results were obtained when data of many fertilizer trials were investigated to arrive at preliminary validation of norms and indexes. These norms, indexes, nutrient sufficiency ranges, and critical intervals can be used for prediction of growth, yield, and nutrition disorders of sugar beet.

Water is one of the most essential parameters for crop production. There is a direct relation between crop yield and water use in plants. Agriculture in arid regions has special aspects. In these areas, agriculture is limited by water and irrigation. Therefore, agricultural practices are organized for optimum water use and maximum yield per unit volume of water which is used. Sprinkler irrigation is one of the methods which has important role in suitable use of water and increasing water use efficiency (WUE). In this research, water use efficiency and yield (quantity and quality) of sugar beet in sprinkler and furrow irrigation was studied in Mashhad, Karaj and Esfahan. In the first year, experiments were done in three locations based on T student test without replications. In the second year, experiments were done in three replicates with randomized block arrangement in Mashhad and Karaj. Irrigation treatments were sprinkler, conventional and cut back furrow irrigation. Water requirement in sprinkler irrigation treatment was calculated based on Penman-Monteith method. Ordinary furrow irrigation treatment applied according farmer's conventional methods. Also, cut back irrigation treatment was applied based on reducing irrigation discharge to 0.6-0.7 after delivering of water to the end of furrows. Results showed that there were significant different in root yield, net and gross sugar yield, water use efficiency and sugar content between experimental regions. However, there was significant difference in root yield and water use efficiency between irrigation treatments. The sprinkler irrigation treatment produced the highest root yield (56.5 ton/ha). The cut back and conventional furrow irrigation treatments produced root yield of 48 and 43.6 ton/ha, respectively and were place in the same statistical level. Root and gross sugar water use efficiency in sprinkler irrigation treatment were 5.55 and 0.86 kg/mЗ, respectively. This treatment was better and has significance difference with two other irrigation treatments. Although, cut beck irrigation had better performance compared to conventional furrow irrigation but in overall, sprinkler irrigation treatment had better performance in used water, irrigation efficiency, root yield, sugar yield and WUE with respect to furrow irrigations. According to obtained results, it is recommended that in regions with limited water resources, sprinkler irrigation has been applied for increasing yield and WUE. However, in region with limitation in application of sprinkler irrigation methods (such as high ¬speed winds, heavy soils, etc.), it is recommended that modified furrow irrigation method such as cut back method has been applied for increasing irrigation efficiency and WUE.

Microirrigation has the potential to minimize water droplet evaporation and wind drift losses associated with sprinkler irrigation, improving the irrigation control by frequent applications, providing the needed nutrients for crops through the system, minimizing deep percolation and improving crop yield. This study was conducted to evaluate sugar beet yield under conventional and alternate tape and furrow irrigation. The sugar beet pp22 was cultivated with 0.3 m row spacing. There were four treatments of tape irrigation (tapes from Iranian and foreign manufacturers) and two treatments of furrow irrigation. In each treatment four rows of sugar beet were grown. Alternate and every row irrigation was applied for both tape and furrow irrigation treatments. The amount of water used, irrigation application efficiency (Ea), water use efficiency (WUE), coefficient of uniformity (CU) of applied water and fertilizer in tape irrigation, white sugar percentage, gross sugar percentage, root yield, white sugar yield, gross sugar yield, the WUE of root yield, and the WUE of white sugar and gross sugar were assessed in a field experiment near the College of Agriculture of Shiraz University. The results showed that the amount of water used in tape irrigation treatments was 50 percent less than furrow irrigation treatments. The average Ea of tape and furrow irrigation was 90.7% and 52%, respectively. The CU of Iranian and foreign tape was 97% and 98%, while the CU of applied fertilizer was 97.5% and 94.5%, respectively. The highest white sugar percentage was found in alternate tape irrigation; however, the highest gross sugar percentage belonged to alternate furrow irrigation treatment. The highest root yield was obtained from Iranian tape irrigation treatment of all rows. The highest gross sugar yield was found in furrow irrigation; however, there was no significant difference among all treatments for white sugar yield. The amount of water used in tape irrigation was 58% of furrow irrigation, while the highest WUE of root yield, white sugar yield and gross sugar yield was found in the alternate tape irrigation. These values were the least for conventional furrow irrigation.

To explore the on-farm strategies which result in higher economic gains and water productivity (WP), a physically based agro-hydrological model, Soil Water Atmosphere Plant (SWAP), was calibrated and validated using intensive measured data at 8 selected farmer fields (wheat, fodder maize, sunflower and sugar beet) in the Borkhar district, Isfahan during the growing seasons of 2004-05. The WP values for the main crops were computed using the SWAP simulated water balance components i.e. transpiration (T), evapotranspiration (ET), irrigation (I), and the marketable yield (Y)M in terms of YM T -1, YM ET -1 and YM I -1. The average WP, expressed as YM T -1 (kg m-3) was 1.18 for wheat, 3.38 for fodder maize, 0.33 for sunflower and 1.72 for sugar beet. This indicated that fodder maize provided the highest economic benefit in the Borkhar irrigation district. Soil evaporation caused the average WP values, expressed as YM ET-1 (kg m-3), to be at least 11 to 27% lower than the average WP, expressed as YM T-1. Furthermore, due to percolation from root zone and stored moisture content in the root zone, the average WP values expressed as YM I-1 (kg m-3), had a 24 to 42 % reduction as compared with WP expressed as YM ET-1. Improved irrigation practices in terms of irrigation timing and amount, increased WP in terms of YM I-1 (kg m-3) by a factor of 1.5 for wheat and maize, 1.3 for sunflower and 1.1 for sugar beet.