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下野地灌区位于准噶尔盆地的西南边缘,是玛纳斯河流域主要垦区之一。灌区南接天山北麓冲积扇缘,北抵沙漠,气候干旱,年降雨量仅180—240毫米,蒸发量超过降雨量的8—13倍,为一典型的大陆性荒漠气候。地下水位较深,除炮台、小拐农场沿玛纳斯一带及下野地局部地区地万水位较高外,一般均在5—8—10米以下,不能或很少直接供土壤毛细管的地面蒸发。地下水矿化度较高,大部分大于20毫克/升,化学类型为SO_4~Cl~-—Ma~+—Ca~（++）,局部地区为—SO—HCo_3~-—Na~+—Ca~（++）。 由于古代和现代积盐过程的结果,本区大面积分布着盐化—碱化灰棕色荒漠土,占总面积的80—90%,并且有60—70%属于强度盐化、强度碱化土壤。土壤含盐量（1米土层平均）一
Underwater irrigation area is located in the southwestern edge of the Junggar Basin, Manas River Basin is one of the main reclamation area. Irrigation south of Tianshan Mountains alluvial fan north edge of the desert arrived in the north, arid climate, the annual rainfall of only 180-240 mm, the evaporation of more than 8-13 times the rainfall, a typical continental desert climate. The groundwater level is deeper, except for the high water level in the areas along the Manas area and the sub-surface areas of the Fort and Xiaoguai farms, generally below 5-8-10 meters, with little or no direct evaporation to the ground surface of soil capillaries . The degree of mineralization of groundwater is high, most of them are more than 20 mg / L, the chemical type is SO_4 ~ Cl ~ - Ma ~ + -Ca ~ (++), and the local area is -SO-HCo_3 ~ - Na ~ + -Ca ~ (++). As a result of the ancient and modern process of salt accumulation, salinized-alkalized gray-brown desert soil is distributed in a large area in this area, accounting for 80-90% of the total area and 60-70% of it is intensity salinization and strong alkalized soil . Soil salt content (1 m soil average) One