Investigating the Possibility of Autumn-Sown and Determining the Most Suitable Planting Date and the Best Bolt-Resistant Cultivar of Sugar Beet in Khorasan Region

IntroductionSugar beet (Beta vulgaris L.) is the second most important sugar crop after sugarcane, which annually produces about 40% of total sugar production worldwide and is adapted to different climatic conditions (El-Hag et al., 2015). Due to global warming, autumn cultivation of sugar beet is predicted to become more priority in the future, but autumn cultivation is in danger of bolting and flowering in many areas. Excessive bolting reduces sugar content, root yield, and purity of raw syrup. In general, both early sowing and delayed sowing reduce root yield, sugar, and leaf area index and increase the percentage of impurities. Therefore, this experiment was designed and implemented with the aim of feasibility study of autumn cultivation of sugar beet and determination of the best planting date in North, Razavi, and South Khorasan provinces for three new varieties resistant to sugar beet.Materials and MethodsThe experiment was conducted as a split-plot design based on a randomized complete block design with three replications in the provinces of North Khorasan (Shirvan), Khorasan Razavi (Mashhad), and South Khorasan  (Khezri Dasht-e Bayaz) in 2019-2020. The main plots included three planting dates (2, 7, and 12 October) and the subplots included three bolt-resistant sugar beet cultivars (Giada, Merak, and Sharif). Each plot consisted of 6 rows with a length of 5 m, at a distance of 50 cm and a distance between two plants of 20 cm, and planting was done manually. To determine root yield from the middle rows of each plot by eliminating the margin, harvest was done at an area of 4 m2. A sample of root paste of each treatment was sent to the Beta Lizer laboratory of Mashhad Agricultural Research and Agricultural Services Company to determine the percentage of sugar. Other quality parameters were measured by Beta Lizer (Braunschweig method). Using the polarimetry method (Sucromat), the percentage of sugar content and white sugar yield, and other quality parameters were calculated for all experimental plots. Combined analysis of variance for different locations and mean comparison based on least significant difference (LSD) at the level of 5% probability using SAS 9.4 software was performed. Also, the graph plots were performed using Excel software.Results and DiscussionThe results of the analysis of variance showed that the interaction effects of the location and cultivar were significant on bolting percentage, root yield, sugar content, Na content, yield coefficient, and white sugar yield. The first planting date (October 2) in Mashhad region for all three cultivars led to the highest percentage of bolting (78-90%). Delay in planting date from 2 October to 12 October, the bolting percentage of cultivars was reduced, significantly. The bolting percentage in Shirvan region was less than 8%. On the third planting date (October 12) in all regions, cultivars showed also a bolting percentage of less than 10%. Giada cultivar in Mashhad region with 47.3 ton.ha-1 had the highest and Sharif cultivar in Shirvan region with 22.6 ton. ha-1 had the lowest root yield. Shirvan region had less root yield than the other two regions. The highest sugar content (18.78%) belonged to Giada cultivar in Shirvan region and the lowest sugar content (13.01%) was observed in Sharif cultivar in Mashhad region. The planting date of 12 October was significantly lower in impurities, alkalinity coefficient, and molasses compared to earlier planting dates. The first planting date had the lowest (62.3%) and the third planting date had the highest (74.2%) extraction coefficient. Giada cultivar in Shirvan region had the highest extraction coefficient (78.1%) and the lowest extraction coefficient (60.8%) belonged to Sharif cultivar in Mashhad region.ConclusionIn Shirvan and Khezri regions, Giada cultivar but in Mashhad region, Merak cultivars had the highest white sugar yield. In general, the results showed that in Shirvan region, planting on 2 October and in Mashhad and Khezri regions planting on 7 October could lead to reaching maximum white sugar yield

Study of Changes in Long-term Wheat Production Trend and Factors Affecting it in North Khorasan Province: I- Irrigated Wheat

IntroductionOne of the main challenges of modern agriculture in ensuring food security is development of strategies to deal with potential negative impacts and adapt to climate change. To address this challenge, it is crucial to investigate the effects of climatic factors on agricultural production at a spatiotemporal dimension, develop and utilize crop management decision-support tools, and support targeted agronomic research and policy. These endeavors necessitate the availability of accurate and standardized meteorological data.Studying growth degree days and wheat phenology can significantly enhance our understanding of how wheat growth responds to climate change and aid farmers in adapting to and effectively mitigating its influence.Materials and MethodsTo determine the environmental and management factors affecting the yield of irrigated and rainfed wheat in different regions of North Khorasan province, we investigated the trend of yield changes from 1980 to 2009. Subsequently, we simulated the wheat plant growth stages using the DSSAT model and analyzed the impact of temperature and rainfall changes on yield through panel data analysis. Panel data analysis is a widely used statistical method in social science, epidemiology, and econometrics for analyzing two-dimensional (typically cross-sectional and longitudinal) panel data. This method involves collecting data over time from the same individuals and conducting regression analysis across these two dimensions.Results and DiscussionAccording to the results of this study, 63% of the changes in irrigated wheat yield between the years 1980-2009 can be attributed to environmental factors (temperature and precipitation), while 37% can be attributed to management factors. When comparing environmental parameters, it was observed that the number of temperatures above 30°C (N30TMAX), mean temperature (GSTMEAN), interaction of amount and frequency of precipitation (TPRAT * NPRAT) significantly affect yield (p ≤ 0.05). Bojnord, Shirvan, and Esfarayen regions exhibited significant positive cross-sectional effects in terms of environmental parameters, whereas Farooj, Raz-Jargalan, Maneh Semelghan, and Jajarm regions displayed negative cross-sectional fixed effects.A study examining the critical stages of wheat growth during good years (with high wheat grain yield) and poor years (with low wheat grain yield) revealed that in all weak years, the minimum temperatures fell below the critical level (-11°C). The occurrence of very low temperatures during the early stages of growth and primary leaf production, which is the plant establishment stage, resulted in reduced photosynthesis levels and subsequently severe yield reduction.In all regions and for 100% of the studied years, irrigated wheat in the grain-filling stage experienced temperatures above 30°C, leading to negative cross-sectional effects in Farooj, Raz-Jargalan, Maneh-Semelghan, and Jajarm. The frequency of temperatures above 30°C during the hard dough stage of irrigated wheat was higher than that during the soft dough stage in all regions. Therefore, delaying the planting date from October (the common planting date in the studied areas) would result in conflicts with high temperatures during the soft dough stage and negative temperatures during the primary leaf production stage and plant establishment at the beginning of the growing season, severely reducing yield.ConclusionIn general, the results of this study demonstrated that implementing effective management methods, particularly selecting the appropriate planting date, can lead to better adaptation of wheat's phenological stages to environmental conditions. This, in turn, has the potential to enhance wheat yield

Prediction of water retention of soils from the humid tropics by the nonparametric k-nearest neighbor approach

Nonparametric approaches such as the k-nearest neighbor (k-NN) approach are considered attractive for pedotransfer modeling in hydrology; however, they have not been applied to predict water retention of highly weathered soils in the humid tropics. Therefore, the objectives of this study were: to apply the k-NN approach to predict soil water retention in a humid tropical region; to test its ability to predict soil water content at eight different matric potentials; to test the benefit of using more input attributes than most previous studies and their combinations; to discuss the importance of particular input attributes in the prediction of soil water retention at low, intermediate, and high matric potentials; and to compare this approach with two published tropical pedotransfer functions (PTFs) based on multiple linear regression (MLR). The overall estimation error ranges generated by the k-NN approach were statistically different but comparable to the two examined MLR PTFs. When the best combination of input variables (sand + silt + clay + bulk density + cation exchange capacity) was used, the overall error was remarkably low: 0.0360 to 0.0390 m(3) m(-3) in the dry and very wet ranges and 0.0490 to 0.0510 m(3) m(-3) in the intermediate range (i.e., -3 to -50 kPa) of the soil water retention curve. This k-NN variant can be considered as a competitive alternative to more classical, equation-based PTFs due to the accuracy of the water retention estimation and, as an added benefit, its flexibility to incorporate new data without the need to redevelop new equations. This is highly beneficial in developing countries where soil databases for agricultural planning are at present sparse, though slowly developing

Validation of Grid APHRODIT Daily Precipitation Estimates and Estimates derived from spatial interpolation of Precipitation in the Khuzestan province

Available accurate and reliable precipitation data are so important in water resources management and planning. In this study,to determine the best method of regional precipitation estimate in Khuzestan province, estimated daily precipitation data from the best interpolation method and APHRODIT Daily Grid Precipitation data during the 2000-2007 years were compared with 44 meteorological stations. Four interpolation methods i.e. Inverse Distance Weighted, Ordinary Kriging, Cokriging, and Regression Kriging were assessed to determine the most appropriate interpolation method for daily precipitation.For the variography analysis in Kriging models, five variogram models including spherical, exponential, linear, linear to sill and Gaussian fitted on the precipitation data. Near neighbor method was used to compare APHRODIT Daily Precipitation data with station recorded data. Cross validation technique was employed to evaluate the interpolation methods and the most appropriate method was determined based on Root Mean Square Error,Mean Bias Error, Mean Absolute Error indices and regression analysis. The result of error evaluation of interpolation methods showed that regression Kriging method has the highest accurate to interpolation of daily precipitation data in Khuzestan province. Therefore, regression-based interpolation methods which using covariates would be improved precipitation evaluate accurate in the area. Comparison of error indices and regression analysis of regression Kriging interpolation method and estimate of APHRODITE show that on most days the accurately estimate of regression Kriging is higher than the APHRODITE. Therefore to understanding of spatial distribution and estimate of daily precipitation data in Khuzestan Province, Regression Kriging interpolation method is more accurate than available APHRODITE dat

The association of crop production and precipitation; a comparison of two methodologies

This study compares two methods for evaluating precipitation effects on wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) yield, which have been cultivated for 30 years under two different climate conditions (semi-arid and Mediterranean). The distribution and amount of precipitation were indexed and their relationship with the corresponding crop yields (1984\u20132013) was investigated. The concentration index (CI), i.e. the contribution of the days of greatest precipitation to the total amount of precipitation, was also calculated as an alternative approach. Both methods were used to analyze the whole crop growing season, from planting to harvest, and for two critical growth stages, germination and anthesis. It was observed that there was a significant correlation between yield and the average daily precipitation (ER; rwheat=0.74** and rbarley = 0.75**) during the whole growing season, irrespective of the crop type, whereas there was no significant impact on crop yield due to the non-uniformity of precipitation distribution (UR). However, when a critical stage like anthesis was evaluated over a shorter period, a significant correlation between UR and crop yields (rwheat=0.56** and rbarley=0.64**) was found. The results indicated that these indexes are very effective for predicting crop yields based on their association with final yield within critical growth stages. In addition, it was also found that a proposed model using both indexes (ER and UR), with high correlation (r = 0.84**) can be very effective in estimating crops performance. The results also showed that the sensitivity of crop yield to the uniformity of precipitation during the critical growth stages was lower than when the whole growing season was considered. The CI index was less effective in reflecting the distribution of precipitation in the semi-arid and Mediterranean conditions compared with the UR

Quantitative Analysis of Growth and Production of Two Local and Commercial Cultivars of Radish (Rhaphanus sativus L.) in Response to Different Levels of Planting Density

Abstract\ud In order to compare the growth indices and phenological stages of development of two local and commercial varieties of radish in response to different levels of population, an experiment was conducted as factorial on the basis of completely randomized block design in the greenhouse in Ferdowsi University of Mashhad, Iran during 2009-2010. Treatments were included two varieties of radish as first factor and three levels of population containing 85, 120 and 170 Pl m-2 as second factor. Phenological stages and growth indices including fresh and dry weight, leaf area, relative growth rate, special leaf area, leaf area ratio, net assimilation rate, edible part yield and dry matter allocation to leaves and roots in optimal conditions since the beginning of germination until final harvest were analyzed. The results showed that there is no significant difference between two varieties in relation to the germination time and 2 and 4 leaves stages in different planting densities. But two varieties responded differently to the different planting densities since the beginning of tubering. The local variety showed higher leaf area ratio and leaf area index, and higher intercepted radiation, but the allocation of photosynthate was more to leaves than edible root. Commercial cultivar showed significantly more economic yield than local cultivar. Increasing the population to170 pl m-2 significantly increased leaf area and leaf area index, radiation use efficiency, leaf weight and biomass, but it had no significant effect on the radish root weight.\ud \ud Keywords: Growth analysis, Planting density, Rhaphanus sativus, Relative growth rat

Ecological Intensification by Increasing Radiation Use Efficiency in a Low Input Agro-Ecosystem of Fenugreek

In ecological or sustainable intensification, increasing the agricultural productivity and enhancing ecosystem services is possible through improving resource and input-use efficiency. In order to estimate the radiation use efficiency and radiation interception of Fenugreek (Trigonella foenum-graecum) under different treatments of animal manure, a completely randomized block design with three replications and four treatments was conducted on the research farm of Faculty of Agriculture, Ferdowsi University of Mashhad. Treatments at four levels including 15, 20, 25 and 30 tons of animal manure per hectare were designed. The results showed that the growing season of Fenugreek was coincident with absorbed radiation by canopy, so the time to reach the maximum leaf area index was in accordance with the time to reach the maximum incident radiation by canopy of Fenugreek. The lowest leaf area index (0.22) and radiation use efficiency (1.42 g Mj-1) was obtained with the application of 15 ton ha-1 animal manure and highest leaf area index (0.30). And radiation use efficiency (1.74 g Mj-1) was obtained with the application of 25 ton ha-1 animal manure. The results also indicated that increasing the animal manure enhanced leaf area index and consequently radiation use efficiency, but this advantage was seen only up to a certain level of animal manure application (25 ton ha-1). Thus, sustainable intensification is attainable in a low input agro-ecosystem by improving radiation use efficiency as an appropriate indicator and without any application of additive manure