Crop and Soil modeling

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Data and information for the Crop and Soil modeling group.


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    ALSIM 1 (LEVEL 2) User's Manual
    Fick, Gary W. (Department of Agronomy, Cornell University, Ithaca, NY 14853, 1981)
    ALSIM 1 (LEVEL 2) is a dynamic computer simulation model of alfalfa (Medicago sativa L.) growth and management written in the computer simulation language CSMP III. The model was developed primarily for studies of the management of defoliating pests of the alfalfa ecosystem. It is a refinement of ALSIM 1 (LEVEL 1), and for most applications it should be used in preference to LEVEL 1. The main improvement in LEVEL 2 is a soil water budget allowing for simulation of the effects of limiting soil water supply on alfalfa growth. Under most conditions, it will more accurately predict seasonal yield distributions than will LEVEL 1. Over-winter use of stored food reserves has also been added to LEVEL 2. Input data needed for LEVEL 2 are (a) yields of leaves, stems, basal buds, and total non-structural carbohydrate reserves (TNC) at the start of simulation; (b) soil water holding capacity of the root zone; (c) dates of harvest; (d) latitude of the study location; and (e) daily weather data for solar radiation, mean air temperature, and precipitation. The model predicts the yield of alfalfa hay and the growth curves for leaves, stems, basal buds, and TNC with simulated time steps of one day. It also simulates the supply of available water in the root zone on a daily basis. The model assumes largely pure stands of alfalfa, and it does not include growth limitations caused by excess soil water content. Neither does the model predict root growth and yield, assuming a root system sufficient to extract the available water. A discussion of model development, performance, and use is included in this report.
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    ALSIM 1 (Level 1) Users' Manual
    Fick, Gary W. (Department of Agronomy, Cornell University, Ithaca, NY 14850, 1975)
    ALSIM 1 (Level 1) is a dynamic computer simulation model of alfalfa (Medicago sativa L.) growth and management written in CSMP. Condition of the crop at the start of simulation, dates of cutting, and solar radiation and average air temperature data are needed as input. The model predicts yield of hay and growth curves for leaves, stems, basal buds, and total nonstructural carbohydrates of the taproots (TNC) with time steps of one day. Following a simulated harvest, the model overestimates top growth and underestimates TNC levels, apparently because of insufficient understanding of the regrowth processes. The most significant contribution of the model is the identification of the importance of and need for research in the area of regrowth physiology. A discussion of model performance, instructions on how to use the model, and examples of simulation runs are included in the report.
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    Input and Output Data in Studying the Impact of Meat and Fat on the Land Resource Requirements of the Human Diet and Potential Carrying Capacity: The New York State Example
    Peters, Christian J.; Wilkins, Jennifer L.; Fick, Gary W. (Department of Crop and Soil Sciences, Cornell University, Ithaca, NY 14853 USA, 2005-12)
    Consumer dietary preferences influence the amount of land needed for food production. We modeled the impact of fat and meat consumption on land requirements for food production in the context of New York State (NYS). This publication contains the input data used to create a spreadsheet-based model and the output data from the program. Per capita land resource requirements were calculated for 42 diets ranging from 0 to 381 g/day (0 to 12 oz/day) of meat and eggs and 52 to 117 g/day of fat (20 to 45% of total calories). All diets contain equal numbers of total calories, and many meet national dietary recommendations. The potential human carrying capacity of the NYS land base was then derived based on recent estimates of available agricultural land.