A Research Method for Semi-Automated Large-Scale Cultivation of Maize to Full Maturity in an Artificial Environment

Matthew Wiethorn,James Camberato,Chad Penn

doi:10.3390/agronomy11101898

Abstract

There are unique advantages and disadvantages to using the field, greenhouse, growth chamber, and media-less techniques for growing maize (Zea mays L.) for research purposes. Soil-buffered nutrients such as phosphorus (P) do not allow for precise control of solution concentrations in the field, while greenhouses, growth chambers, and hydroponics provide limiting conditions. The objectives of this study were to develop a practical technique for productively cultivating several maize plants from seed to physiological maturity (R6) in a grow room environment, with precise control of nutrient availability and timing, and evaluate its utility for the purpose of measuring plant responses to variations in nutrient concentrations. The construction and testing of a semi-automated grow room for conducting nutrient studies on 96 maize plants utilizing simulated or artificial conditions are described. Plant growth response to a range of solution phosphorus (P) concentrations was tested to evaluate the utility of the technique. Maize yield components were measured and compared to values for field-grown plants. Due to ideal conditions and successful simulation of light intensity, diurnal fluctuations in temperature and RH, and changing photoperiod, grain yield and tissue nutrient concentrations were comparable to field-grown maize, although with greater shoot biomass. Plants responded positively to increased P concentrations in fertigation. The technique can be used for large-scale plant nutrient studies that require precise control of bioavailability and timing as well as manipulation of light intensity and photoperiod duration.

Highlights

IntroductionThe dynamic nature of soils can present further variability in cases where the objective is to focus on the plant instead of the soil
Ninety-six maize plants were grown to full maturity (R6) under fully artificial conditions with semi-automation and produced realistic maize plants with corresponding grain yields, thereby achieving all the benefits without the disadvantages of field, greenhouse, growth chamber, and traditional hydroponics studies, with regard to nutrient research
Nutrient injectors used in this study were less accurate when operated at lower flow rates or flow times compared to higher flow rates

Summary

Introduction

The dynamic nature of soils can present further variability in cases where the objective is to focus on the plant instead of the soil For this reason, the traditional alternatives to field experiments that allow for focus on plant growth are growth chambers and greenhouses. Growth chambers offer year-round experimentation under any desired conditions with precise control of all plant growth parameters such as, temperature; relative humidity; light quality, quantity, and duration, along with the ability to program all these parameters to change temporally. Greenhouse experiments typically supplement light with metal halide and/or high-pressure sodium lighting [5] One disadvantage with these types of lighting is their variation in light quality distribution across the wavelengths of the electromagnetic spectrum and light quantity production when compared to natural sunlight. The second major problem with these types of lighting is the high amount of heat they produce to reach a given light intensity and the consequent problem of dissipating this heat [6]

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