关键词: 水稻, 缓释尿素, 养分吸收动态, 养分累积, 产量

Abstract:

【Objective】Slow release urea, as a new type of fertilizer for both single basal and decreasing fertilization, is the guarantee of high crop yield due to its nutrient release characteristics corresponding to crop nutrient requirements. This study explored the effect of co-application of slow-release urea and common urea on nutrient absorption in whole growth period of rice which could provide theoretical support and technical guidance for new fertilizer development. 【Method】Field experiments in early and late rice were set up with six different treatments described as below: No N fertilization (CK), 100% slow-release urea (100%SRU), 75% of slow-release urea and 25% of common urea (75%SRU+25%CU), 50% of slow-release urea and 50% of common urea (50%SRU+50%CU), 25% of slow-release urea and 75% of common urea (25%SRU+75%CU), 100% of common urea (100% CU). The nitrogen treatments were fertilized with 150 kg N·hm^-2, and all the experimental fields were fertilized with 55 kg P₂O₅·hm^-2 and 130 kg K₂O·hm^-2, which were supplied by calcium superphosphate and potassium chloride. Rice plant samples of early rice were collected to analyze N, P and K concentrations during growth period. Leaves of different positions and grains of early rice were collected during filling stage to analyze N, P and K concentrations, and SPAD values were also measured at the same stage. The yield and yield components were also recorded after the early and late rice harvest. 【Result】Results showed that the highest yields of the early and late rice were both occurred under the 75%SRU+25%CU treatment, and there were no significant differences between 100% SRU, 50%SRU+50%CU and 25%SRU+75%CU treatments in early and late rice, and all better than 100%CU treatment in some extent. Compared with the 100%CU treatment, the advantages of combined application of the slow-release urea treatments were that the rice had higher effective panicles and number of grains per ear, especially in early rice. Throughout the growth period, the dry matter weight and N accumulation of shoot in 100% SRU treatment were significantly higher than those of the other treatments, and were decreased with the increase of the proportion of the common urea. The concentration of N in shoot treated with 100% SRU was also significantly higher than those of the other treatments, and was also decreased with the increase of the proportion of the common urea. During the grain filling stage, the N contents of flag leaf, penultimate and third leaves, and grain, and SPAD values of flag leaf were all significantly increased by the application of 100%SRU, and were all decreased with the increase of the proportion of common urea. 【Conclusion】The 100% of SRU treatment provided excess nitrogen and made the rice appeared different degree of greedy situation, and then decreased grain yield. 75%SRU+25%CU has been proved adequate for single basal fertilization in rice production. Due to all of the slow-release urea addition treatments had the better yield than 100%CU treatment in this experiment, because of its cost, the proportion of the slow-release urea could be reduced in some degree.

Key words: rice (Oryza sativa L.), slow-release urea, nutrient uptake dynamics, nutrient accumulation, yield