تاثیر شوری آب آبیاری و تراکم بر کیفیت علوفه دو اکوتیپ خارشتر (.alhagi camelorum fisch)

خارشتر گیاهی چند ساله و شورزی است که قابلیت تولید علوفه در اراضی شور را دارد. به منظور بررسی تغییرات کیفیت علوفه این گیاه تحت تاثیر شوری و تراکم در دو اکوتیپ خارشتر، آزمایشی در قالب اسپلیت فاکتوریل بر پایه طرح بلوک‌های کامل تصادفی با 3 تکرار در دو مکان(بیرجند و سربیشه) اجرا گردید. کرت‌های اصلی شامل سطوح شوری آب آبیاری(3.5، 7.5 و 12 دسی‌زیمنس بر متر، ناشی از کلرید سدیم ) بودند. کرت‌های فرعی ترکیب سطوح اکوتیپ (وشمگیر و کرند) و تراکم (10 و 20 بوته در متر مربع) بودند. در پایان فصل رشد مقادیر پروتئین، چربی و خاکستر خام، فیبر حل‌شونده در شوینده اسیدی و خنثی، انرژی متابولیسمی و ماده خشک قابل هضم علوفه، مورد بررسی قرار گرفت. پروتئین خام تحت تاثیر شوری به طور معنی‌داری کاهش یافت، لیکن چربی خام در دو اکوتیپ مورد مطالعه عکس العمل متفاوتی نسبت به شوری نشان داد، به گونه‌ای که با افزایش شوری چربی خام در اکوتیپ کرند کاهش و در اکوتیپ وشمگیر افزایش معنی‌داری یافت. افزایش تراکم در بیرجند منجر به افزایش معنی‌دار انرژی متابولیسمی و کاهش معنی‌دار فیبر حل‌شونده در شوینده اسیدی گردید ولی در سربیشه تاثیر معنی‌داری بر این صفات نداشت. افزایش تراکم بوته در سطح شوری 12 دسی‌زیمنس بر متر منجر به کاهش معنی‌دار فیبر حل‌شونده در شوینده خنثی شد، ولی در سایر سطوح شوری آب آبیاری، اثر آن معنی‌دار نبود. اعمال شوری منجر به کاهش معنی‌دار عملکرد علوفه‌تر گردید ولی افزایش شوری از 7/5 به 12 دسی‌زیمنس بر متر تاثیری بر عملکرد علوفه نداشت. کیفیت علوفه تولیدی در سربیشه بالاتر از بیرجند بود، هر چند اکوتیپ کرند در بیرجند و اکوتیپ وشمگیر در سربیشه کیفیت علوفه بالاتری را نشان دادند. بر اساس نتایج حاصله، در سطوح بالای شوری آب آبیاری، کشت خارشتر با تراکم بالاتر، می‌تواند منجر به تولید علوفه با کیفیت‌تری شود.

effect of irrigation water salinity and plant density on forage quality of two camelthorn (alhagi camelorum fisch.) ecotypes

introductioncamelthorn (alhagi camelorum fisch.) is a perennial plant with shrub growing form belonging to fabaceae family, which is native to large area from mediterranean to russia. camelthorn is very high tolerant to salinity and this is one of the halophytic plants. by using halophytic plants, many products can be produced in saline areas, which one of these products is forage needed by livestock. one of the most important areas for the development of camelthorn cultivation is saline lands that have been excluded from cultivation due to irrigation with saline water for many years that increasing soil salinity. therefore, it is necessary to investigate the plant forage quality in field conditions with irrigation by saline water. materials and methodsthe experiment was conducted as split-factorial in a randomized complete block design with three replication in two locations (farms of the faculty of agriculture in the birjand university and hojjatabad farm of peyvand khavaran agro- industry in sarbishe) at years of 1399. the effect of location was considered fixed. the experimental factors was included ecotype at two levels (voshmgir and korond), plant density at two levels (10 and 20 plant per square meter) irrigation water salinity at 3 levels (3.5, 7.5 and 12 ds/m). the main plots were included irrigation water salinity levels and the sub-plots were included from a combination of density and ecotype levels. the amounts of crude protein, crude fatty acids, crude ash, acid detergent fiber, neutrals detergent fiber, metabolizable energy, and digestible dry matter of camelthorn forage were measured at the end of the growing season.results and discussionthe results showed that by increasing salinity to 7.5 ds/m had not significant effect on the crude protein percentage, but with a further increase in salinity to 12 ds/m the crude protein was decreased (7.2%) significantly compared to control (figure 2a). the forage fatty acids of sarbishe were significantly higher (5.3%) than birjand, which is due to the lower temperature of sarbisheh region. the crude forage ash content in birjand was significantly higher (5.3%) than sarbishe (figure 1a).with increasing the density from 10 to 20 plants per square meter the forage ash was increased (7.5%) significantly (table 5). in birjand, metabolizable energy was increased (2.2 %) significantly with increasing plant density, but in sarbishe, increasing density had not effect on this trait (figure 5a). irrigation water salinity application in both places and ecotypes studied was not significant effect on the metabolizable energy of camelthorn forage. voshmgir ecotype in birjand had significantly (11.4%) more acid detergent fiber than korond ecotype, but the difference between these ecotypes was not significant in sarbishe (table 7). with increasing plant density in birjand, the value of acid detergent fiber was decreased (7.9%) significantly but the difference between two plant densities was not significant in sarbishe (figure 6). at the 12 ds/m irrigation water salinity level, increasing the plant density let to a decrease (14.5%) of neutral detergent fiber, while increasing the plant density at lower irrigation water salinity levels had no effect on this trait (table 3).conclusionalthough increasing the irrigation water salinity led to a significant reduction in camelthorn forage protein, but the amount of protein obtained at 12 ds/m irrigation water salinity (12.29%) was also acceptable. high irrigation water salinity levels in both ecotypes and locations did not lead to a significant reduction in forage metabolizable energy, so it is possible to produce adequate quality forage by cultivation camelthorn with saline water. korond ecotype was more suitable for cultivation in birjand and voshmgir ecotype was more suitable for cultivation in sarbishe and produced better forage in these locations. in saline conditions, it is better to cultivate camelthorn with high plant density, because in this case, the amount of forage fiber will decrease and the forage quality will increase.