一、问题的提出土壤是作物赖以生长的基础,它为作物提供丰富的营养物质。长期以来,人们在考虑土壤供给作物营养物质,特别在讨论到土壤养分储量时,习惯上总是以壤耕层土30万斤干重为基数进行计算的[30万斤=耕作层厚度(20厘米计)×6670000厘米~2×耕作层土壤容重(1.16计)÷500)。很明显,仅仅以耕作层养分的储量来衡量,或者以此作为施肥计算的主要依据,必然导致与客观实际不完全相符合的结果。这是因为土 First, the issue raised Soil is the basis for crop growth, which provides rich nutrients for crops. For a long time people have been considering the supply of crop nutrients to soils and, in particular, when discussing their nutrient reserves, they have traditionally been calculated on the basis of a dry weight of 300,000 kg of soil [300,000 kg = tillage thickness (20 Cm) × 6670000 cm ~ 2 × tillage soil bulk density (1.16 dollars) ÷ 500). Obviously, the mere assessment of the reserves of nutrients in cultivated layers or as the main basis for the calculation of fertilization inevitably leads to the results that are not completely consistent with the objective reality. This is because of soil