第三章作物布局 Crop composition and distribution 作物布局的意义、原则和步骤 Concept and importance of crop composition and distribution 作物生态适应性 Ecological adaptability of crops第三章 作物布局 Crop composition and distribution 作物布局的意义、原则和步骤 Concept and importance of crop composition and distribution 作物生态适应性 Ecological adaptability of crops