فراتحلیل اثر آرایش کاشت و سامانه آبیاری بر عملکرد و بهره‌وری مصرف آب در تولید سیب‌زمینی

مطالعات دربارۀ اثر آرایش کاشت بر عملکرد و بهره‌وری مصرف آب در تولید سیب‌زمینی در سطح بین‌المللی و ملی سابقه ای طولانی دارد. با این همه، به دلیل پراکندگی تیمارها و تفاوت یافته‌های پژوهشی، نتیجه‌گیری و توصیۀ کلی برای کاربرد تیمارهای مناسب مشکل است. هدف از این پژوهش استفاده از رهیافت فراتحلیل برای جمع‌بندی نتایج پژوهش‌ها در خصوص اثر آرایش کاشت بر عملکرد و بهره‌وری آب در تولید سیب‌زمینی است. برای این منظور مقاله های متعدد علمی پژوهشی منتشرشده توسط پژوهشگران داخلی و خارجی در خصوص آرایش کاشت سیب‌زمینی بررسی، غربال گری و تحلیل شد. در پژوهش‌های مرتبط با بررسی اثر آرایش کاشت بر عملکرد و بهره‌وری آب در تولید سیب‌زمینی به‌طور معمول از تیمارهای شاهد و آزمایشی استفاده شده است. فاصلۀ ردیف‌های کاشت سیب‌زمینی در آزمایش‌های مختلف 60، 75، 120 و 150 سانتی‌متر به‌صورت‌ یک ردیفه و دو ردیفه و با سامانه‌های آبیاری قطره‌ای و بارانی گزارش شده است. در تیمار شاهد با فاصلۀ ردیف 75 سانتی‌متر، میانگین عملکرد 33000 کیلوگرم در هکتار و میانگین بهره‌وری مصرف آب 5/46 کیلوگرم به ازای هر مترمکعب آب بود. تلفیق یافته‌ها نشان داد افزایش عملکرد با تغییر فاصلۀ کاشت از تیمار شاهد 75 سانتی‌متر به 60 سانتی‌متر 33 درصد، به 120 سانتی‌متر 18 درصد و به 150 سانتی‌متر 8 درصد است. هرچند اعمال تیمارهای فاصلۀ کاشت روی بهره‌وری مصرف آب ازنظر آماری معنی‌دار نبوده است، اثرهای مثبت جزئی نسبت به تیمار شاهد مشاهده شده است. بیشترین تاثیر مثبت در فاصلۀ کاشت 60 سانتی‌متری (10 درصد) بوده است. تغییرات عملکرد و بهره‌وری آب در کاشت‌های دو ردیفه نسبت به کاشت های یک ردیفه با سامانۀ قطره‌ای به‌صورت کاهشی به اندازۀ 7 درصد و با سامانۀ بارانی به‌صورت افزایشی با تغییر عملکرد به اندازۀ 4/6 درصد و بهره‌وری آب به اندازۀ 16 درصد گزارش شده است.

meta-analysis of the effect of planting patterns and irrigation systems on potato yield and water productivity

extended abstractintroduction potato is a plant with a lot of nutritional value that is cultivated and produced in more than 150 countries of the world. potato production of this product is increasing, due to the high adaptability to different climate conditions in the world. the annual global production of potato is 310 million ton, which is obtained from 23 million ha of agricultural land in the world. the cultivated area of potato in iran in the crop year of 2017-2018 was 154000 ha with the production of more than 5 million tons.  in total, 55% of the cultivated area and about 60% of the annual production belong to hamedan, ardabil, isfahan, kordestan, east azarbaijan and lorestan provinces. studies on the effect of planting patterns on yield and water productivity in potato production have a long history at the international and national levels. it is difficult to draw general conclusions and recommendations for the application of appropriate treatments due to the differences in treatments and research findings. therefore, the objective of this study was to apply a meta-analysis approach to summarize the results of several investigations on the effect of planting patterns on yield and water productivity in potato production.methodologyseveral scientific papers published by international and national researchers on potato planting patterns were reviewed, screened, and analyzed. control and experimental treatments have been applied in studies on the investigation of the effect of planting patterns on yield and water productivity in potato production. the spacing of potato planting rows in different experiments including 60, 75, 120, and 150 cm has been reported as a single-row and/or two-row under drip and/or sprinkler irrigation systems.the steps of meta-analysis are briefly described below.a) the intensity of relationships between variables cannot be determined by statistics or statistical tests. therefore, it is necessary to apply effect measurement indicators. one of these indicators is the effect ratio index (r). the effect ratio (r) is obtained from the ratio of the average traits measured in the research treatment to the average traits in the control treatment. these traits included yield and water productivity in potato production.b) the percentage of changes in the traits resulting from the experimental treatment (ch %) compared to the control treatment is obtained from the following relationship:results and discussionthe average yield of potatoes was 33000 kg ha-1 and water productivity was 5.46 kg m-3 in the control treatment with row spacing of 75 cm. the combined results showed that increased yield by changing the planting spacing from 75 cm to 60 cm 33%, to 120 cm 18%, and to 150 cm 8%, respectively. while the application of planting spacing treatments on water productivity was not statistically significant. minor positive effects were observed compared to the effect of the control treatment. the highest positive effect was in the planting spacing of 60 cm (10%). changes in yield and water productivity in two-row cultivations compared to single-row under the drip system decreased by 7%, while increased yield and water productivity were 4.6% and 16% under the sprinkler system, respectively. conclusionthe findings on the effect of planting patterns on yield and water productivity in potato production, have a lot of diversity and variance results. therefore, the optimal planting patterns in potato production has not been determined. meta-analysis, as a powerful approach, has led to precise findings to integrate the findings of planting patterns researches under different irrigation systems. in this study, statistical comparisons were made between potato planting rows from 60, 75, 120 and 150 cm as one and two- row under drip and sprinkle irrigation systems based on potato yield and water productivity. in the control treatment with row spacing of 75 cm, the yield and water productivity averaged 33000 kg ha-1 and 5.46 kg m-3, respectively. the findings showed that the increase in yield by changing the distance from 75 cm to 60 cm was reported by 33%, to 120 cm by 18% and to 150 cm by 8%. the effect of planting distance treatments on water productivity was not statistically significant. however, partial positive effects were observed compared to the control treatment. the highest positive effect (10%) was in distance of 60 cm. changes in yield and water productivity in two-row patterns compared to one- row with drip system decreased by 7% and with sprinkle system, yield  increased by 4.6% and water productivity by 16%.