After selected various high yielding and hybrid varieties, their nutrient uptake pattern, interaction among fertilizer, varieties and plant density should be investigated. 近年來(lái),我國選育出一批主要作物的高產(chǎn)品種和雜交種,應當研究它們的需肥特性,研究施肥與這些新品種及其種植密度等不同措施的關(guān)系。