Relationships among weed suppression effect, allelopathy and agronomic characteristics of Oryza longistaminata and related descendants Effect of Seedling Age on the Seedling Quality and Field Performance of Pinus koraiensis Effect of Panicle Nitrogen Fertilizer Management on Yield and Population Quality in Mechanical Transplanted Super Rice Ningjing 1 with Different Seedling Ages Effects of Sowing Density, Fertilizer Amount in Seedbed and Seedling Age on Seedling Quality and Grain Yield in Paddy Field for Mechanical Transplanting Rice Age-based Variation of Several Drought-resistance Physiological Characteristics for Juniperus sabina