紫色重碳酸盐硝泥田是四川省一种较为普遍的低产田。当地农民统称“硝田”或叫“换水硝”、“鸭屎硝”、“斑鸠硝”、“热硝”等。主要分布在川东南地区的泸县、隆昌、富顺、高店、江安、南溪和宜宾等县主产水稻的浅丘地区,具有石灰岩露头或富含碳酸钙母质岩层区域中。在以下四种情况下均可出现:自流井层中具有石灰岩露头的逆倾坡落;川东南折皱群向西南延伸尾部的向斜轴部,重庆层具有富含碳酸钙母质的紫红色砂页岩层区域中;嘉定层与重庆层交界的紫红色岩层区域中;重庆层的紫红色岩层中夹有厚层砂姜露头的地方。多则万亩成片,亦有带状或零星分布。该地区的土壤只要长期受富含重碳酸盐(主要是重碳酸钙)水分径流的浸渍,就会形成紫色重碳酸盐硝泥田(以下简称硝泥田)。硝泥田区域旱地和田埂上生长有喜碱性的柏树、马桑、黄荆、刺 Purple bicarbonate salt paddy field is a more common low yield field in Sichuan Province. Local farmers collectively referred to as “Nita” or “change water nitrate”, “duck feces nitrate”, “spot dove nitrate”, “hot nitrate” and so on. Mainly distributed in the southeastern Sichuan Lu County, Longchang, Fushun, Gaodian, Jiang’an, Nanxi and Yibin county main producing rice shallow hill area, with limestone outcrops or areas rich in calcium carbonate parent rock. In the following four cases can occur: the artesian layer with limestone outcrop reverse slope; South Sichuan fold group to the southwest extension of the tail of the syncline axis, the Chongqing layer has a calcium carbonate matrix rich purple sandstone shale Area; in the area of ​​purple-red rock strata at the boundary of Jiading and Chongqing; in the purple-red rock of Chongqing, there is a place where thick sand ginger outcrops are sandwiched. More mu mu into films, there are ribbons or sporadic distribution. The soils in this area will form purple bicarbonate and nitrate fields (hereinafter referred to as “nitrate fields”) as long as they are impregnated with runoff from heavy bicarbonate (mainly heavy calcium carbonate) water for long periods of time. In the muddy field of the muddy field, the cypress trees, the magasin, the yellow vines and the thorns