Evolution Characteristics of Agronomic Traits in Cultivar Replacement of Early Season Indica Rice Evolution characteristics of population quality during genetic improvement in early season indica rice cultivars Content and evolution characteristics of organic carbon associated with particle-size fractions of grey desert soil under long-term fertilization. Evolution characteristics of soil particulate organic carbon in the paddy field with long-term planting green manure Evolution characteristics of organic carbon fractions in gray desert soil under long-term fertilization