Effects of Nitrogen Application Rate on the Growth and Nutrient Accumulation of Pitaya Shoots

Key words: 
• pitaya /
• nutrient accumulation /
• nitrogen nutrition /
• nutrient elements

Abstract: One-year-old plants of pitaya（ Hylocereus undulatus） were treated with nitrogen fertilizer at the rate of 0（ T0）,130（ T1）,185（ T2）,245（ T3） or 345 kg·hm^-2（ T4） to study the effects of different application rates of nitrogen fertilizer on the root system and growth of young pitaya plants. The results showed that nitrogen fertilizer promoted the growth of pitaya lateral shoots. The content of nitrogen in the shoots of pitaya plants under5 treatments ranged from 17. 49 g·kg^-1to 18. 59 g·kg^-1,the phosphorus content from 4. 86 g·kg^-1 to 6. 18g·kg^-1,and the potassium content from 57. 01 g·kg^-1 to 61. 28 g·kg^-1. The distribution of different nutrient elements in the same position of pitaya plants was different,and the distribution or accumulation of the same nutrient element in different parts of the pitaya plants was also different. The cumulative content and total cumulative content of nitrogen,phosphorus and potassium of each pitaya plant in each treatment accounted for 1. 70%,0. 45%,5. 75% and more than 8% of the total dry weight,respectively. The application of nitrogen fertilizer resulted in a lower root/shoot ratio of the young pitaya plants. The contents of mineral elements in the aboveground parts of the pitaya plants were all in the order of K ＞ N ＞ P. K content was 3 times higher than N content,or 12 times higher than P content. In pitaya production fertilizer with high potassium is recommended.