پایش عوامل محدود کننده تولید پتانسیل و خلاء عملکرد برنج در شالیزارهای قائمشهر.

Background and objectives: The continuation of the progressive and growing trend of global population growth and income, will lead to an increase in food demand and consequently more agricultural production. On the other hand, the escalation of climate anomalies also threatens the food security of human society in the future. It is very unlikely that this food need will be met by expanding the area under cultivation, due to the lack of water resources and suitable agricultural lands, and increasing non-agricultural uses due to urban development. Also, in an agricultural production system, there are often huge differences between the yields of a plant and a region. This prompted researchers to assess the reasons for the potential lack of performance and to fill existing gaps and improve performance. Due to the need to increase rice production in the country, the present study was conducted to determine the quantity of potential yield and yield gap in the study area and the constraints that play a role in increating a yield gap and the implementation of best management. Materials and methods: In this study, three groups of information related to crop management, soil and crop (including 160 variables), during the two agronomic years 2019 and 2020 out of a total of 164 farms including local and high-yield rice cultivars in 36 villages of Ghaemshahr located in Mazandaran province were measured and recorded in the field with continuous monitoring during the growing season and through face-to-face interviews with farmers. Statistical analysis was performed using comparison performance analysis. The relationship between yield and all variables examined with the help of multiple regression. In addition, the scope of changes and the method of performing each management operation and the proportion of farmers who had used different methods of management operations were determined. Results: From 160 variables studied, the performance model (final production equation) with nine independent variables was selected, which explained 73% of the total performance changes (P <0.0001). The model estimated the average and maximum yields to be 5163 and 11598 Kg ha-1, respectively, which are comparable to the average and maximum yields observed on the farm (at 5243 and 11052 Kg ha-1 ). The yield gap in the production equation was 6435 Kg ha-1. There is a gap of 6435 Kg ha-1 between the actual yield of farmers on the farm and the achievable yield. It was also found that low yield cultivar, planting date, number of seedlings per hill, square planting arrangement, total amount of urea fertilizer, total amount of ammonium sulfate fertilizer, total amount of potassium sulfate fertilizer, loam clay texture, and previous plant in rotation of legume type, 35, 8, 9, 3, 15, 12, 12, 2 and 4% are involved in creating this gap, respectively. Conclusion: Comparative performance analysis is one of the statistical methods that by analyzing field data is able to present the effect of various factors on the final amount of product performance. Based on the available results, it can be stated that the accuracy of the performance model (final production equation) is appropriate and by identifying the main causes of production constraints, in estimating the amount of yield gap and determining the effective contribution of each of the performance limiting variables and better giving the relevant which is done with the aim of increasing production per unit area, to provide considerable assistance. [ABSTRACT FROM AUTHOR]