مدل‌سازی تولید ذرت دانه‌ای در سناریوهای مختلف مدیریتی در استان کرمان

امروزه بهره‌گیری از رهیافت مدل‌سازی به‌عنوان ابزاری مفید برای بهینه‌سازی تولید محصولات کشاورزی در نظر گرفته می‌شود. هدف این مطالعه استفاده از مدل زراعی apsim جهت ارزیابی تولید ذرت در 3 منطقه (بردسیر، جیرفت و ارزوئیه) در استان کرمان با استفاده از آزمایش‌های شبیه‌سازی بلندمدت (1397-1379) در 3 تاریخ کاشت (زودهنگام، مرسوم و دیرهنگام) و 3 تیمار آبیاری (11، 13 و 15 نوبت) بود. قبل از استفاده، مدل با استفاده از اطلاعات آزمایشات مزرعه‌ای اجراشده در منطقه موردمطالعه مورد واسنجی و ارزیابی قرار گرفت. واسنجی و ارزیابی مدل apsim در پیش‌بینی عملکرد بیولوژیک، عملکرد دانه و صفات فنولوژیکی هیبرید ذرت سینگل‌کراس 704 تحت تاثیر مقادیر مختلف نیتروژن (0، 92 و 368 کیلوگرم در هکتار) انجام شد. نتایج نشان داد که مدل apsim قابلیت خوبی در شبیه‌سازی عملکرد بیولوژیک، عملکرد دانه و مراحل فنولوژیکی گیاه در دو مرحله واسنجی (مقدار nrmse به‌ترتیب 14.8، 11.23 و کمتر از ده درصد) و مرحله اعتبار‌سنجی (مقدار nrmse به‌ترتیب 13.9، 9 و کمتر از پنج درصد) داشت. عملکرد دانه در مناطق مختلف متفاوت بود به طوری که در سراسر تیمارهای تاریخ کاشت و آبیاری، بیشترین عملکرد دانه ذرت در شهرستان بردسیر با 8317 کیلوگرم در هکتار و کمترین مقدار آن در شهرستان جیرفت با 4735 کیلوگرم در هکتار مشاهده شد. در بین تاریخ کاشت‌های مختلف تاریخ کاشت‌های دیرهنگام عملکرد دانه بیشتری (8529 کیلوگرم در هکتار) تولید کردند. همچنین در تیمارهای مختلف آبیاری، بیشترین عملکرد دانه به‌ترتیب با 6317، 5919 و 5671 کیلوگرم در هکتار در تیمارهای 15، 13 و 11 نوبت آبیاری به‌دست آمد. در تمام مناطق مورد مطالعه عملکرد بهینه دانه ذرت (8872.8کیلوگرم در هکتار) در اثر متقابل تاریخ کاشت دیر هنگام در 15 نوبت آبیاری به‌دست آمد.

modeling maize production under different management scenarios in kerman province

introduction agriculture is a cornerstone of many developing economies, providing food, income, and employment for millions of people. it is also projected to play a vital role in feeding a global population of 9.1 billion people by 2050. however, there are growing concerns about the environmental impact of agriculture, particularly in arid and semi-arid regions like iran. managing water and fertilizer usage in agriculture is crucial to ensuring food security and sustainability. however, conducting field experiments to assess the interaction of all factors involved is expensive and time-consuming. this research focuses on optimizing maize production in kerman province, a region where maize is a major crop. the research is motivated by the need to improve resource management in iran, where water and fertilizer resources are limited. the apsim model is used to determine the best management scenario for maize production in kerman province. apsim is a crop growth simulation model that can be used to predict the impact of different management practices on crop yield, water use efficiency, and nutrient use efficiency. the use of apsim in this research provides a cost-effective and time-efficient alternative to conducting extensive field experiments. the results of this research will contribute to the development of sustainable and efficient agricultural practices in kerman province and similar regions. these regions are characterized by resource constraints, such as limited water and fertilizer availability. the research aimed to simulate the effect of management parameters (planting date and irrigation) on crop yield and subsequently achieve the optimal management scenario.materials and methodsthe apsim model was used for simulation in three regions of bardsir (temperate to cold climate), jiroft (hot and humid climate), and orzuye (hot and dry climate). the model requires four series of data: climate, soil, management, and crop data. the required climate data (from 1998 to 2018) including daily maximum and minimum temperatures, length of sunny hours, and daily precipitation were collected and prepared from the synoptic weather stations of the three mentioned regions.the management data set for each of the study regions was prepared in the form of questionnaires and field research from experts of the agricultural jihad organization, the agricultural research center organization, and prominent farmers in those regions. the crop data includes the plant genetic coefficients of the maize single cross hybrid 704, which were obtained from the calibration of the apsim model. to optimize planting date and irrigation management in the studied areas, different planting and irrigation date treatments were investigated. in this research, planting date treatments included the conventional planting date of the region, 20 days before the conventional planting date (as early planting date), and 20 days after the conventional planting date (as late planting date). irrigation treatments included the usual number of irrigations in the region (13 irrigations), less irrigation (11 irrigations), and more irrigation (15 irrigations).results and discussionour results showed that the model successfully simulated maize phenology, especially maturity date, with high accuracy for all fertilizer amounts tested. the model performance in predicting biomass under different nitrogen treatments was also satisfactory, with a minimal difference between observed data and model results. the nrmse of grain yield in the calibration stage was 11.2% and in the validation stage was 9%. the nrmse for calibration of the biological yield of sc 704 was 14.8% and for validation was 13.9%. also, the model was able to simulate phenology with very high accuracy (especially the days to maturity). overall, the nrmse of days to flowering was less than 10% and for the days to maturity was less than 5%. late planting dates consistently showed better performance across regions and irrigation treatments, resulting in significantly increased grain yield compared to conventional and early planting dates. the highest seed yield was obtained with 15 times of irrigation, among the various irrigation treatments. late planting combined with 15 times of irrigation yielded the best results in kerman province, particularly in bardsir, with a yield of 9300 kg ha-1. optimal moisture and air conditions, along with the cultivation of a late-maturing variety, contributed to the higher seed yield. these findings are consistent with previous research that has confirmed the positive impact of late planting and extended ripening periods on maize yield.conclusionour results showed that the model simulates the growth and yield of single cross 704 corn in kerman province well, even after 20 days of late planting. long-term simulation experiments showed that maize grain yield varied depending on the region, with the highest yield in bardsir (8317 kg ha-1) and the lowest yield in jiroft (4735 kg ha-1). the optimum maize grain yield (8872.8 kg ha-1) was obtained by the interaction effect of late planting date and 15 times of irrigation.