A Study on Response of Sugarcane Genotypes to Phosphorus Fertilizer in Western Guangdong, China

: To optimize Phosphorus (P) fertilization, three sugarcane genotypes (ROC22, LC5135, and YT236) widely cultivated in western Guangdong, China were used for the experiment in which 5 levels of P fertilizer were set up to study the effects of their application. The results showed that: (1) P fertilization amount within 288 kg/hm 2 P 2 O 5 could increase the plant height, stem diameter, and weight and yield of sugarcanes. The yield of ROC22 was 14% more than LC5136 and 33% more than YT236. (2) The sucrose yield of ROC22, YT236, and LC5136 increased firstly, followed by leveling off or no significant change with the increase of P fertilizer. The sucrose yield of ROC22 with 288 kg/hm 2 P 2 O 5 was significantly higher than other treatments. The average yield of ROC22 was 15% higher than that of LC5136 and 35% higher than that of YT236. (3) The P fertilizer use efficiency of ROC22 and LC5136 increased firstly and then decreased and that of YT236 always decreased with increasing levels of P fertilizer application. Considering the yields of sugarcane and sucrose and the use efficiency of P fertilizer, the optimum P fertilizer amounts of ROC22 and LC5136 were 288 kg/hm 2 and that of YT236 was 192 kg/hm 2 . The growth of ROC22 was better than that of LC5136 and YT236.