Tuesday, 8 November 2005
9

This presentation is part of: Precision Farming and Remote Sensing in Agricultural Systems

Calibration of a Potato Growth Model for Prediction of Nitrogen Dynamics in Potato Systems in the Pacific Northwest.

Javier Marcos, Claudio Stockle, Ashok Alva, Dennis Timlin, and V.R. Reddy.

Tools to improve nitrogen (N) management for potatoes in the Pacific Northwest (PNW) are desirable in view of the concern on non-point source pollution of nitrate into groundwater in the Columbia Basin production region which is characterized by sandy soils and possible N inputs in excess of crop N requirement. A potato growth model was developed and integrated into the multi-year, multi-crop simulation mode CropSystVB to improve overall model capabilities for the assessment of N fate under different nitrogen and irrigation regimes in potato systems. In the integrated model, CropSystVB simulates the soil-water-plant-atmosphere system for a crop rotation, as well as the soil water and nitrogen budgets. When the crop in rotation is potato, the potato model simulates potato growth and development and plant carbon and N balances. A field experiment was conducted to obtain crop data required to parameterize the potato crop model under different levels of N and irrigation. Model simulations were compared to seasonally measured data of dry matter, leaf area index, plant N and yield of potatoes grown with 3 levels of applied N (168, 336, and 504 kg/ha) and 2 levels of applied water (100 and 75% ET). Results showed that the model simulated plant N and dry matter partition and yields adequately. Improved accuracy in the simulation of potato N and carbon balances by the integrated model demonstrates that this model can be used to predict soil and plant N dynamics and production of potato-based cropping systems.

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