Modelling development and growth of the potato crop influenced by temperature and daylength: LINTUL-POTATO

Abstract

Abstract. A model 'LINTUL-POT ATO' is described which bases total dry matter production on light use efficiency of intercepted light by a potato crop. The course of light interception by green leaves initially is temperature-sum dependent and is also steered by influences of daylength and temperature on assimilate partitioning. Dry matter allocation to the foliage, which determines the final length of the growing period, is determined by a day length and temperature dependent period between emergence and tuber initiation and subsequent partitioning of dry matter to the tubers. Once the tuber daily growth rate equals total crop dry matter accumulation, no more foliage is formed and the crop senesces faster at higher temperatures. The aim of this paper is to explain effects of temperature and daylength on total tuber production from the effects of these environmental factors on the underlying processes. The relative effect of temperature on rates of emergence, light use efficiency, tuber initiation and tuber growth, and, the effect of daylength on development rate until tuber initiation are represented quantitatively. Potential tuber production at some temperature and day length regimes is calculated exploratively and compared with results from the literature. The model can be used to simulate tuber dry matter production in specific environments and to select cultivars for such environments with suitable temperature and daylength reactions on tuber initiation and dry matter partitioning so as to maximise yields.

Developing environmental principles, criteria, indicators and norms for potato production in South Africa through field surveys and modelling

“…The LINTUL crop growth model used in the present study calculates potato dry matter production from the amount of intercepted radiation by its green foliage and a constant conversion factor (light use efficiency) (Spitters, 1990). The current LINTUL model for potatoes followed the approach of Kooman and Haverkort (1994) by calculating the temperature-dependent phenological development of a potato crop. In general, higher temperatures lead to earlier crop emergence and a more rapid initial leaf growth.…”

“…Moreover, very high temperatures reduce photosynthesis and thereby biomass accumulation. Potato varieties react differently to temperature and day length, so parameters in Kooman and Haverkort's (1994) model were variety-specific.…”

“…Daily biomass growth was calculated using the crop's LAI, light interception (using an extinction coefficient of 1 (Spitters and Schapendonk, 1990)), and the light use efficiency (1.25 g dry matter MJ À1 of intercepted light). In the model, photosynthesis capacity was reduced when the average day temperature fell below 16°C or when the maximum temperature exceeded 30°C and was completely halted at temperatures below 2°C and above 38°C (Kooman and Haverkort, 1994). Besides temperature, drought stress limited photosynthesis and slowed down foliar expansion.…”

“…The actual transpiration by the crop, and thereby the water-limited photosynthesis rate, equalled the potential evapotranspiration by the crop multiplied by a drought stress factor, which was a function of the plant available water in the soil. The harvest index was set at 0.75; the tuber dry matter concentration at 20% (Kooman and Haverkort, 1994).…”

Evapotranspiration and Water Management for Crop Production

“…The model simulated fresh tuber yields ranging from 4 to 56 t ha -1 resulting from differences in weather patterns, soils, cultivars, and management practices (Bowen, 2003). The LINTUL-POTATO simulation model (Kooman & Haverkort, 1995) establishes potential yield of a certain cultivar for a determining growing period and plant density and is based on incident photosynthetically active radiation (PAR), the fraction of PAR intercepted by the crop, and radiation use efficiency to produce dry matter. The potential yield established with this model was used by Caldiz & Struit (1999) to perform a preliminary yield gap analysis regarding actual and attainable potato yield in different areas of Argentina, and provided estimates ranging from 47 to 126 t ha -1 .…”