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一、前言 近年来,锌肥的施用日益引起人们的重视,特别在pH偏碱,碳酸钙含量较高的石灰性土壤上,一些对锌敏感的作物,如玉米、水稻等,施用锌肥的效果愈来愈明显。我国北方土壤缺锌面积颇大,黄土上发育的褐土,黑塿土、黄绵土、风沙土等,有效锌含量都低于临界值。因而对玉米、水稻等作物施用锌肥,都有不同程度的增产效果,例如用0.01—0.05％的硫酸锌溶液浸玉米种,0.1—0.2％的硫酸锌溶液叶面喷施,都能达到一定的增产效果。 但是,在施用锌肥时,对固锌能力强的土壤,施锌量少,不能满足作物全生育期的需要,施用量大,则会出现作物对锌的奢侈吸收,甚至能使作物中毒。 pH和CaCO_3含量是影响土壤锌有效性的两个重要因素。pH和土壤有效锌含量呈负相关,可用方程y=4.4-0.487·pH表示,y系有效Zn含量(ppm),pH上
I. Introduction In recent years, the application of zinc fertilizer has drawn increasing attention, especially in calcareous soil with high pH and alkali and calcium carbonate content. Some zinc-sensitive crops, such as corn and rice, are treated with zinc fertilizer The effect is more obvious. Zinc deficiency in northern China is quite large, with the development of loess, black loess, loess and aeolian sandy soil on loess, the effective zinc content is below the critical value. Therefore, corn, rice and other crops with zinc fertilizer, have different levels of yield, for example, with 0.01-0.05% zinc sulfate solution soaked corn, 0.1-0.2% zinc sulfate solution foliar spray, can reach a certain The yield effect. However, in the application of zinc fertilizers, zinc fertilizers are deficient in zinc-fixing soils and can not meet the needs of the whole growth period of the crops. When the zinc fertilizers are applied in large quantities, the plants may absorb extravagant zinc and may even poison the crops. pH and CaCO_3 content are two important factors that affect soil zinc availability. pH and soil available zinc content was negatively correlated, available equation y = 4.4-0.487 · pH, y system effective Zn content (ppm), pH