稻作中的肥水管理，是通过土壤而对根起作用的。若能了解根形成于何时、何处，其生育情况怎样，生理活性如何（根的机能=根量×根活性），对于适当的栽培管理是有益处的。但根系的调查有许多困难，在田间几乎不能进行。在此想介绍在田间水平的比较容易的调查方法，特别是“不必 Fertilizer and water management in rice works through roots and soil. It is beneficial for proper cultivation and management if one can understand when and where the root is formed, how it is born, what its physiological activity is (root function = root mass × root activity). However, root surveys have many difficulties and can hardly be carried out in the fields. We want to introduce relatively easy investigation method at the field level here, especially "do not have