عنوان

جریان آب و نمک در خاک‌های شالیزاری ترک‌دار و تاثیر آنها بر عملکرد گیاه برنج

‭۱۳۳۳۵پ‬

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جریان آب و نمک در خاک‌های شالیزاری ترک‌دار و تاثیر آنها بر عملکرد گیاه برنج

/فاطمه سلحشور دلیوند

: کشاورزی

چاپی

of Guilan paddy rice fields, cracking of soils will be inevitable and loss of irrigation water is the most important challenge. Investigation of crack geometry characteristics and the procedure of crack development in surface paddy rice field with 2, 3, 4 and 5 dSm-1 soil salinity at both laboratory and farm scale showed that change of soil volume is started by vertical shrinkage and in all treatments crack incidence occurs close to soil saturation moisture. Although soil salinity delayed the development of cracks, it increased the mean values of widths and depths of cracks by passing time,Investigation of simultaneous effects of salinity and drought stress on rice plant (Hashemi Cultivar as the dominant cultivar of Giulan province) showed that the best model to predict the water uptake reduction is the Homaee and Feddes (1999) model.Yield reduction due to drought stress threshold is 80 percent of the saturated soilmoisture and salinity threshold equals 2.83 dSm-1. Effects of drought and salinity stresses on horizontal and vertical flow in cracking paddy rice field showed that when the medium size of cracks developed at the soil surface, continuous irrigation caused higher yield even with low quality water, as compared to intermittent irrigation with 6-day interval. In spite of using less volume of water in intermittent irrigation treatments, the highest water productivity was belonged to continuous flood irrigation treatments at the crack initiation stage. Furthermore, the medium size of crack in soil surface increased lateral seepage significantly. The effect of irrigation water salinity on lateral seepage was not significant and cracks were not fully closed after wetting of the soil. Effects of water qualitative and quantitative management at the end of tillering stage of rice plants in regional scale showed that probability of crack initiationnd development in more paddies at southwestern and west parts of the study area wathe highest in the whole area. Consequently, loss of irrigation water and risk drought stress increasing and soil salinization are is higher in these areas. At tmentioned areas, clay and organic carbon content are higher and the thickness of surface layer of paddy soil is les

دکتری

‮‭۱۳۹۳/۰۲/۲۵‬

تبریز

تلفیق اطلاعات خواص هیدرولیکی خاک، هندسه ترک ها و چگونگی پاسخ گیاه برنج به تنش خشکی در مقیاس مزرعه با مدل های شبیه سازی فرآیندهای فیزیک خاک و گیاه، زمین آمار و سیستم اطلاعات جغرافیایی ‮‭GIS‬ ابزاری امید بخش برای مدیریت بهینه آب در شرایط محدودیت کمی و کیفی آب در مقیاس ناحیه ای است.

سلحشور دلیوند، فاطمه

سیاه و سفید

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