دانلود ترجمه مقاله تاثیر آب و هوای نیمه خشک و مدیریت سفره آب بر شوری خاک و عملکرد یونجه – نشریه اسپرینگر

فهرست مطالب:

چکیده
مقدمه
مواد و روش ها
ساخت لایسی متر
جمع آوری داده
داده های اقلیمی
رطوبت خاک
شوری خاک

بخشی از ترجمه:

یک آزمایش لایسی متر برای بررسی تاثیر مدیریت سفره آب WTM روی توزیع شوری خاک و عملکرد یونجه یک ساله(Medicago scutellata) انجام شد.آبیاری هایی با سه سطح سفره آب یعنی ۰.۵ (WT0.5)، ۰.۷ (WT0.7) و ۱.۰ m(WT1.0) و تیمار آبیاری سنتی زهکش آزاد برای این مطالعه انتخاب شدند.همه تیمارها در قالب طرح بلوک های کاملا تصادفی با سه تکرار انتخاب گردیدند.نتایج این مطالعه نشان داد که هدایت الکتریکی متوسط خاک عصاره ااشباع در ناحیه ریشه به تدریج افزایش یافت و به بیش از مقدار آستانه طراحی شده (۴ دسی زمیتر) بعد از نخستین برداشت علوفه در لایسی مترهای کارگذاشته شده در زیر زمین رسید.انباشت بیشتر نمک در تیمار WT0.5 مشاهده شد.عملکرد و وزن متوسط خشک یونجه یک ساله در WT0.5 و WT0.7 به ترتیب ۵۲ و ۷۳ درصد نسبت به تیمار شاهد بیشتر بود.

۱ مقدمه

مدیریت سفره آب موجب افزایش تولید گیاه و کیفیت آب زهکش در مناطق مرطوب شد(ورکمن و همکاران ۱۹۹۰،کالیتا و همکاران ۱۹۹۲،فیشر و همکاران ۱۹۹۹،جای و همکاران ۲۰۰۶).زهکشی زیر سطحی تاثیر بسزایی بر کیفیت و کمیت تولیدات گیاهی مختلفی دارد و این در حالی است که بسیاری از مطالعات اخیر نشان دادند که بسیاری از گیاهان به طور مطلوبی به عملیات زهکشی کنترل شده و سیستم های آبیاری زیرسطحی واکنش می دهند(ساپی و همکاران ۲۰۰۱،فازی و بیکر ۲۰۰۳،آیرز و همکاران۲۰۰۳).در سیستم زهکشی کنترل شده،خروجی زهکش جهت حفظ بخشی از آب نفوذی در پروفیل خاک به عنوان مکمل نیازهای آبی گیاه تعبیه شد.در سیستم آبیاری زیر سطحی،با این حال، آب از طریق لوله های زهکشی زیرسطحی برای حفظ سفره آب زیر ناحیه ریشه جهت رفع نیازهای آبی گیاهی وارد شد(فازی و بیکر۲۰۰۳).برخی از مزایای نسبت داده شده به WTM به صورت ذیل می باشند:کاهش آب زهکش و مواد شیمیایی،کاهش آلودگی زیست محیطی، و تامین محیط آبی خاکی بهتر برای رشد گیاه(اسکاج و ایوانز ۱۹۹۶،مجا و همکاران ۲۰۰۰).اسکاج و همکاران ۱۹۹۹ به مقایسه عملکرد زهکشی کنترل شده، آبیاری زیرسطحی و سیستم های زهکشی مدیریت آب در یک زمین چهار هکتاری پرداختند.غلظت نیترات آب زهکشی تا ۶۳ درصد در سیستم زهکشی کنترل شده کاهش یافت و مقدار کل نیترات تا ۵۰ درصد در مقایسه با سیستم زهکشی آزاد کاهش نشان داد.محصول گوجه و ذرت در سیستم ابیاری زیرسطحی به ترتتیب ۴۴ و ۶۴ درصد بود.آهنن ۱۹۹۱ افزایش ۱۰ درصدی در عملکرد سیب زمینی در آبیاری زیرسطحی در مقایسه با سیستم زهکشی آزاد نشان داد.مجیا و همکاران ۱۹۹۸ نیز کاهش ۷۵ تا ۸۴ درصدی نیترات و افزایش ۴۲ درصدی عملکرد ذرت را از طریق مدیریت سفره آب گزارش کردند.

بخشی از مقاله انگلیسی:

Abstract A lysimeter experiment was conducted to investigate the eVect of water table management (WTM) on distribution of soil salinity and annual alfalfa (Medicago scutellata) yield. Subirrigations with three levels of water table namely, 0.5 (WT0.5), 0.7 (WT0.7), and 1.0 m (WT1.0) and a free drainage (FD) conventional irrigation treatment were selected for this study. All treatments were arranged in a complete randomized block design with three replicates. The results of this study indicated that the average soil electrical conductivity of the saturated extract (ECe) in the root zone gradually increased and exceeded the designated crop threshold value (4 dS/m) after the Wrst forage harvest in subirrigated lysimeters. A higher salt accumulation was observed at the WT0.5 treatment. The average dry matter yield of annual alfalfa in WT0.5 and WT0.7 treatments was found to be 52 and 73% higher compared with the control treatment, respectively. Introduction Water table management has shown to increase crop production and drainage water quality in humid regions (Workman et al. 1990; Kalita et al. 1992; Fisher et al. 1999; Jia et al. 2006). Conventional subsurface drainage has long been proved to have substantial impact on quality and quantity of various crop productions, whereas many recent studies have shown that many crops respond more favorably to the practice of controlled drainage and subirrigation systems, instead (Soppe et al. 2001; Fausey and Baker 2003; Ayars et al. 2003). In controlled drainage system, the drain outlet is raised to a speciWed level in order to retain a portion of percolating water in the soil proWle to supplement crop water requirements. In subirrigation system, however, water is introduced through subsurface drainage pipes to maintain the water table just below the root zone to fulWll crop water requirements (Fausey and Baker 2003). Some of the advantages attributed to WTM are: reduction in drainage water and losses of chemicals, reduction in environmental pollution, and provision of a better soilwater environment for crop growth (Skaggs and Evans 1996; Mejia et al. 2000). Skaggs et al. (1999) compared the performance of controlled drainage, subirrigation and free drainage systems for management of drainage water in a 4- ha Weld study. Nitrate concentration of drainage water was reduced by 63% in the controlled drainage system and the total nitrate losses were reduced by 50% compared with the free drainage system. Tomato and corn yields in the subirrigation system were 44 and 64% more than those in the free drainage system, respectively. Ahonen (1991) reported a 10% increase in potato yield in the subirrigation as compared to the free drainage system. Mejia et al. (1998) also reported 75-84% reduction of nitrate losses and 42% increase in corn yield through water table management.A study performed on a Ravenna silt loam showed that the average yield of subirrigated soybeans over a 5-year period was 5.22 Mg, whereas the non-irrigated yield over the same period was limited to 3.44 Mg (Fausey and Cooper 1995). Controlled drainage and subirrigation can also improve conservation of water during drought (Skaggs and Gilliam 1981; Evans et al. 1995; Meija and Madramootoo 1998). Lothar et al. (2005) quantiWed the water use eYciency of several crops at shallow water table in temperate climate. They showed that water requirements strongly depend on the level of water control and the type of crops. Freshwater supplies are becoming more limited in dry regions, while the demand for food is increasing globally (FAO 1995a). There are numerous problems in arid and semi-arid regions associated with the practice of surface irrigation using brackish water (FAO 2002). Sensitivity of young plants to saline water and the extent of salt buildup within the root zone during growing season are among the most serious limitations in this respect (Von Hoyningen Huene 1994; Patel et al. 1999). However, a number of studies have reported positive impacts of adopting controlled drainage and subirrigation in arid and semi-arid regions by reducing drainage discharge and saving irrigation water (Abbott et al. 2001; Khalil et al. 2004). Patel et al. (2001) investigated the eVect of initial soil salinity and salinity level of brackish subirrigation water on tuber weight of potato under simulated arid condition. The average root zone salinities were found to be 3.2–۳٫۷ dS/m in lysimeters subirrigated with 1 and 9 dS/m of water, respectively. There was no signiWcant eVect of either initial soil salinity or subirrigation water salinity on the total tuber weight. Therefore, more work is needed to investigate the eVectiveness of WTM on soil salinity proWle and crop yield. Adoption of subirrigation system in semi-arid regions like Khoozestan province in the south and Moghan region in the northwest of Iran is feasible, due to the existence of a shallow water table. Discharge of massive amounts of brackish drainage water from the existing irrigated lands has imposed major environmental problems, which could signiWcantly be tempered using WTM systems. The objective of this study was to investigate the eVect of the subirrigation system on the salt proWle in the root zone of annual alfalfa in the semi-arid climatic conditions of Karaj, Iran. Materials and methods Lysimeter construction The study was carried out in 2005 and 2006 (March–July) in the research Weld at the Soil and Water Research Center of Tehran University (35°۵۶
N, 50°۵۸
E), in the city of Karaj, Iran. The study was conducted with 12 lysimeters installed in the middle of a 0.8-ha Weld (Fig. 1). The soil was excavated in order to place the lysimeters at a certain depth so that their top was on level with the ground surface. The excavated soil was then placed back into the lysimeters and the surrounding space, preserving the proWle similar to the Weld soil. The 1.5-m height lysimeters were made up of 0.7-m diameter polyethylene pipes, with the bottom end sealed with a circular Xat plate. A perforated pipe, 0.05 m in diameter, was installed just above the bottom of each lysimeter to allow the drainage of water through the lysimeter (Fig. 2). In the subirrigated lysimeters, the drain pipes were connected to a gauged riser pipe to maintain and control the water table to the speciWed depth. As the plants were consuming water from the water table, the level of water had to continuously be preserved at the speciWed depth. For this reason, a Marriot system was installed into the control chamber beside the lysimeters to automatically resupply the plant with water (Fig. 1). The depleted amount of water from the storage tank at a certain period of time could then be assumed as the net plant water use. The controlled water level in the lysimeters was also monitored by a piezometer installed in each one.

دانلود رایگان مقاله انگلیسی

خرید ترجمه فارسی مقاله با فرمت ورد

خرید نسخه پاورپوینت این مقاله جهت ارائه