تاثیر شوری آب آبیاری، اکوتیپ و تراکم گیاهی بر عملکرد و غلظت عناصر معدنی اندام هوایی و ریشه خارشتر (.alhagi camelorum fisch)

خارشتر (alhagi camelorum fisch) گیاهی از خانواده بقولات با خواص دارویی و قابلیت تولید علوفه است. به‌منظور بررسی تاثیر شوری آب آبیاری، تراکم و اکوتیپ بر غلظت عناصر معدنی اندام هوایی و ریشه خارشتر پژوهشی در دو منطقه، مزرعه دانشکده کشاورزی بیرجند و حجت‌آباد سربیشه در سال 1399، به‌صورت اسپلیت فاکتوریل در قالب طرح بلوک های کامل تصادفی با سه تکرار انجام شد. سطوح شوری شامل 3.5، 7.5 و 12 دسی زیمنس بر متر به‌عنوان کرت‌های اصلی و سطوح تراکم (10 و 20 بوته در مترمربع) و اکوتیپ (کرند و وشمگیر) به‌عنوان کرت های فرعی به‌صورت فاکتوریل در نظر گرفته شدند. اعمال حداکثر شوری آب آبیاری در مقایسه با شاهد، عملکرد علوفه تر را در بیرجند از 2756 به 1868 و در سربیشه از 2425 به 1931 کیلوگرم در هکتار کاهش داد. همچنین شوری سبب افزایش معنی دار سدیم اندام هوایی در سربیشه از 1.39 به 2.68 درصد و سدیم ریشه در بیرجند از 0.126 به 0.159 درصد و کاهش معنی دار پتاسیم ریشه در سربیشه از 3.94 به 1.78 درصد گردید. با افزایش تراکم منیزیم اندام هوایی در بیرجند از 0.023 به 0.016 و در سربیشه از 0.028 به 0.020 درصد کاهش یافت. همچنین منیزیم ریشه در بیرجند به‌طور معنی داری (از 0.015 به 0.011) و پتاسیم ریشه در سربیشه از 5.6 به 4.8 درصد کاهش یافت ولی سدیم اندام هوایی در هر دو مکان به‌طور معنی داری افزایش یافت. مقادیر منیزیم اندام هوایی خارشتر کمتر از حد مطلوب برای دام بود و کشت با تراکم 20 بوته در مترمربع این مشکل را تشدید نمود. اکوتیپ کرند در سربیشه پتاسیم کمتری نسبت به اکوتیپ وشمگیر داشت بنابراین کیفیت علوفه بالاتری داشت. علوفه تولیدی در سربیشه نسبت به بیرجند پتاسیم کمتری داشت. با توجه به وسعت اراضی شور کشور، توسعه کشت خارشتر می‌تواند به رونق تولید علوفه کمک موثری نماید.

effect of irrigation water salinity, ecotype, and plant density on the camelthorn (alhagi camelorum fisch.) shoot and root minerals concentration and yield

introductioncamelthorn is a perennial plant belonging to fabaceae family. camelthorn tolerance to salinity is very high and it’s a halophyte plant. by using halophyte plants as species with potential for production in saline lands, many outturns can be produced in these areas, one of these products is fodder needed by livestock. salinity and plant density are factors affecting forage quality. increased salinity created by sodium chloride leads to an increase in sodium ions in the plant and affects the balance of sodium to potassium ratio and forage quality. different plant ecotypes and genotypes absorb different amounts of elements in their culture medium. considering that one of the most important areas for the development of cultivation of this plant is saline lands, which have been excluded from cultivation due to irrigation with saline water for many years with increasing soil salinity, it is necessary to study the nutrients changes in plant organs, which is one of the factors affecting forage quality in field conditions with irrigation with salt water. this study investigates the effect of irrigation water salinity in two ecotypes and different densities on the forage yield accumulation of nutrients in shoot and roots in field conditions in two locations.materials and methodsthe experiment was conducted as a split factorial in a randomized complete block design with three replications. the experiment was analyzed in two separate locations. experimental sites included the farm of the faculty of agriculture of birjand university and the hojjatabad farm of peyvande khavaran agro-industry located in sarbishe. the experiment was conducted in 1399. experimental factors include ecotypes at two levels: krond and voshmgir, irrigation water salinity at 3 levels of 3.5, 7.5 and 12 ds.m-1 and plant density at two levels were 10 and 20 plants per square meter. the main plots were considered as salinity levels and the sub-plots were considered as a combination of density and ecotype levels. sampling was performed to measurement the nutrients of shoots and roots of camelthorn in mid-october. shoot sodium, potassium, calcium and magnesium were measured at the end of the growing season.results and discussionthe results showed that there is a negative relationship between the salinity and the forage yield. application of maximum salinity level compare to the control reduced the forage fresh yield from 2825 to 1868 in birjand and from 2425 to 1931 kg.ha-1 in sarbishe. the increase salinity caused a significant increase in shoot sodium in sarbishe from 1.39 to 2.68 percentages and root sodium in birjand from 0.126 to 0.159 percentages and a significant decrease in root potassium in sarbishe from 3.94 to 1.78 percentage of the plant dry matter. with the increase of plant density, the magnesium of aerial parts decreased from 0.023 to 0.016 percentages in birjand and from 0.028 to 0.02 percentages of the plant dry matter in sarbishe. also, root magnesium decreased significantly in birjand (from 0.015 to 0.011%) and root potassium decreased from 5.6 to 4.8 percentages in sarbishe, but shoot sodium increased significantly in both places. the effect of ecotype was significant on shoot sodium and magnesium in birjand, shoot and root potassium and root magnesium in sarbishe.the krond ecotype had less potassium in sarbishe than the voshmgir ecotype statistically significant, so it had higher forage quality. forage produced in sarbishe had less potassium than birjand, so it was of higher quality.conclusionalthough the increase in salinity caused a decrease in the camelthorn forage yield. however, this plant had an acceptable yield in high soil salinity at the end of the season. therefore, it is possible to produce forage in very salty lands through the cultivation of this plant. magnesium levels of camelthorn shoot were less than the required level of livestock and supplementary feeding should be considered to meet the need for magnesium and prevent complications of magnesium deficiency in long-term feeding of camelthorn forage. the shoot potassium is higher than the critical level for livestock and in case of long-term feeding; it should be consumed in combination with low-potassium fodder. also, due to the higher shoot potassium of voshmgir ecotype in sarbishe, the use of krond ecotype is recommended because of the lower potassium level. shoot potassium level in sarbishe was lower than birjand (9 in sarbishe and 12% in birjand), so forage produced in sarbishe was more desirable. the shoot sodium and calcium levels are optimal and there is no need to supplementary nutrition the livestock to provide these elements. although increased salinity increased shoot sodium, it had no effect on potassium (only root potassium in sarbishe decreased with increasing salinity), therefore, in salinity conditions, camelthorn can maintain the potassium level of its shoots and this feature is one of the factors affecting the plant’s tolerance to salinity. increasing sodium concentration was associated with decreasing root potassium concentration, indicating competition of sodium with potassium for uptake. also, higher sodium concentration of shoots than roots can be considered as an effective factor in salinity tolerance by increasing the gradient of osmotic potential from roots to shoots.acknowledgmentsthe authors consider it necessary for the sincere cooperation of peyvande khavaran agro-industry, especially the then formerly managing director of sina sarhadi, the production manager of yahaghi and the manager of hojjatabad farm, abdollahi, as well as the laboratories of animal nutrition and soil science laboratories of ms. khairiyeh. ms. parsa and the farm officials of the faculty of agriculture, university of birjand, who helped us in this research, would be very grateful.