Abstract:

Based on the agricultural statistical data of Ziyang City from 2015 to 2023, this study analyzed the variation characteristics of the total amount of chemical fertilizer, the amount of fertilizer applied per unit area, the variety of chemical fertilizer and the proportion of nutrient input in Ziyang City, so as to provide reference for the green and high-quality development of agriculture in Ziyang City. Based on the analysis of the current situation of fertilizer application and the actual situation of local agricultural production, this paper put forward some countermeasures and suggestions for fertilizer management with the core of optimizing nutrient structure. The results showed that: (1) From 2015 to 2023, the total amount of fertilizer application showed an overall downward trend and went through three stages, including a rapid decline period, a steady decline period, and a gradual stabilization period. In 2023, it dropped to 44000 t, a decrease of 28140 t compared with 2015, with a decrease of 32.13%. (2) The amount of fertilizer applied per unit area in Ziyang City in 2023 was 111.6 kg/hm², a decrease of 6.15% compared with 118.9 kg/hm² in 2015. This was not only lower than the national (292.6 kg/hm²) and Sichuan (315.7 kg/hm²) levels of fertilizer application per unit area, but also far lower than the fertilizer application intensity standard of 250 kg/hm² proposed by the former Ministry of Ecology and Environment. (3) During the period of 2015 to 2023, the main fertilizer types applied in Ziyang City were nitrogen fertilizers (N) and compound fertilizer, which collectively accounted for over 80% every year. The proportion of phosphate fertilizers (P) ranged between 6% and 22%, and potash fertilizers (K) accounted for only 1% to 4%. Overall, the phosphate (P) and potash (K) fertilizers accounted for a relatively small proportion. (4) The N:P:K application ratio changed from 1:0.40:0.11 (2015) to 1:0.67:0.61 (2023). Notably, the ratio in 2021 (1:0.58:0.54) was the closest to the national average. Overall, the N:P:K application ratio remained imbalanced, especially the potassium fertilizers (K) consistently showing the lowest proportion. In summary, from 2015 to 2023, total fertilizer consumption and fertilizer application rate per unit area in Ziyang City showed overall declining trend, basically achieving the goal of “zero growth in fertilizer application”. However, structural imbalances in fertilizer product composition and nutrient input imbalances were persisted. Therefore, it was recommended that the optimization management of chemical fertilizer nutrients should follow the general principles of controlling nitrogen, stabilizing phosphorus and increasing potassium. Scientifically implement measures such as organic fertilizer replacement for chemical fertilizers, water and fertilizer integration, and agricultural mechanization should be extended to ensure the green and high-quality development of agriculture in Ziyang City.

Key words: Ziyang City, chemical fertilizer, current application status, nutrient optimization management, green agricultural development