Economic viability, energy and nutrient balances of site-specific fertilisation for citrus
Colaco, Andre; Gui Pagliuca, Larissa; Liborio Romanelli, Thiago; Molin, Jose Paulo
2020-09-30
Journal Article
Biosystems Engineering
200
138-156
Core objectives of precision agriculture are to improve the economic and environmental performance of agricultural systems. This study evaluated the data from a long-term experiment in citrus to assess whether site-specific nutrient management was successful from these two perspectives. Variable and uniform rate fertilisation treatments were implemented in intercalated strips across two 25 ha citrus groves in São Paulo state, Brazil. To generate variable rate recommendations, information from soil fertility and yield maps were fed into a traditional recommendation formula used by growers. The experiment was carried out for five growing seasons. An economic analysis was conducted. The energy embodied in fertilisers and nutrient balances were used as indicators of environmental impact. Variable rate application reduced fertiliser use in both groves. It increased average yield in grove 1 but sometimes reduced yield in grove 2. As a consequence, profit was increased by 34.7% (an average of US$ 318.5 ha-1 year-1) in grove 1. In grove 2, profit was reduced by 8.5 % (US$ -97.4 ha-1 year-1). Embodied fertiliser energy was reduced by 34% (0.20 MJ kg-1) in grove 1 and by 29% (0.16 MJ kg-1) in grove 2. Nutrient surplus after harvest was reduced by approximately 20 to 70% depending on the nutrient. Maps of economic and environmental indicators showed that site-specific management did not reduce the spatial variability of economic and environmental indicators. The variable rate strategy tested in this study could be improved by using local decision rules based on information about yield potential and soil constraints rather than generalized recommendation formulas. Site-specific analysis of profit, embodied energy and nutrient balance help in assessing system performance and can potentially improve decisions in site-specific nutrient management.
Elsevier
Horticultural Production not elsewhere classified; Agricultural Spatial Analysis and Modelling
https://doi.org/10.1016/j.biosystemseng.2020.09.007
EP201544
Journal article - Refereed
English
Colaco, Andre; Gui Pagliuca, Larissa; Liborio Romanelli, Thiago; Molin, Jose Paulo. Economic viability, energy and nutrient balances of site-specific fertilisation for citrus. Biosystems Engineering. 2020; 200:138-156. https://doi.org/10.1016/j.biosystemseng.2020.09.007
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