Studies on Protein Content in Rice Grain : II. Effects of the fertilization on protein content and protein produtction in paddy grain

[摘要] To prove the effects of the fertilization on protein content of paddy rice, the present experiments were carried out as follows. (1) Planting density was altered as 5O, 80, 110 or 140 hills/3.3m2, and the levels of basaldressing applied were 0.56, 0.75, 0.94 or 1.13kgN/are. The amounts of phosphatic and potassic fertilizer were normally fertilized. (2) In addition to basal dressing, top dressing of 0.05∼0.25g N/hill were applied on various stage before or after heading stage. (3) Two kinds of N, P and K fertilizer experiment paddy fields were used, the one is the usual field continued 12 years for the experiment and the other is newly opened field for the experiment. The results are summarized as follows. 1. As to associated effects of planting density and nitrogen supply on protein content (%) and protein production (protein % × grain yield), it was observed that the more nitrogenous fertilizer applied and the more spacing was wide, the more protein % in rice grain was increased. Ultimately, protein % depends on nitrogen supply per hill. Protein production also tended to increase in higher levels of nitrogenous fertilizer in any planting density, but it was hardly influenced by planting density in any nitrogen levels. 2. The most effective stage of top dressing of nitrogenous fertilizer on the protein % is the heading stage. Before heading stage the effect was slight. After heading stage, the effective period keep on decently long time but the effect make a slow descent gradually. The more nitrogenous fertilizer applied, as top dressing the more protein % was increased and it was more effect to apply all amount of it at the nearer stage to heading date. Top dressing of 0.25g N/hill at the heading stage increased protein content by 38% compared with non top dessing. 3. As to the protein content in rice grain of each plot in N, P and K fertilizer experiment field, in case of usual paddy field, protein % was most high in N P K plot and was inferior any other plots that were excepted each nutrient element. On the other hand, in case of new paddy field with great P-absorptive coefficient, non-application plots of phosphatic fertilizer increased percent of protein by 20-30%compared with N P K plots, but these plots were accompanied remarkably by the decrease in grain yield, consequently reduced the total protein production per unit area.

[学科分类] 农业科学（综合）