Understanding Environment and Soil Quality
Regardless of whether one is growing crops in their backyard or on a large-scale farm, understanding the quality of the environment and the soil is necessary to make informed decisions that affect the quality, nutritional value, and yield of plant-based foods.
Some of the crucial variables that must be monitored include:
Temperature
Extremely high and low temperatures can have adverse effects on the health of plants. High temperatures can cause an imbalance in the photosynthesis and respiration processes that can result in plant suffocation. Conversely, low temperatures can cause plant cells to freeze, which inhibits a plant from getting nutrients.
Humidity
High relative humidity levels prevent a plant from evaporating water as part of its transpiration process. It can also prevent the plant from drawing nutrients from the soil. If these conditions are permitted to continue the plant could rot or suffer bacterial or mold infections.
Moisture Content
The amount of water in the soil must be kept at optimal levels for ideal plant growth. Too much water can result in root rot, which prevents the plant from extracting oxygen from the soil. If there is too little moisture, nutrients cannot circulate through the plant.
pH Level
In chemistry class, we learned the pH scale is a way to indicate the acidity or basicity of a substance. The scale ranges from 0.0 for acids such as battery acid up to 14.0 for bases such as lye. A pH level of 7.0 is considered neutral. Although the ideal pH level can vary from plant to plant, optimum pH levels for soil is between 5.5 and 7.0.
CO2 Level
Plants of all types absorb carbon dioxide (CO2) as part of the photosynthesis process to synthesize food from water (H2O) and CO2. Oxygen (O2), is given off as a byproduct. As with the other factors, too much or too little CO2 can have adverse effects on plant growth and health. As a reference, 250 to 350 parts per million (ppm) is considered a normal concentration in an outdoor ambient environment. Indoor environments with decent air circulation should see a concentration from 350ppm to 1,000ppm.
Project Materials and Resources
This project design uses the Xplained board series from Microchip Technology, which is ideal for rapid prototyping, along with a suite of sensors that will allow the system to monitor the five environmental factors outlined in the previous section. These sensors include the:
- Microchip Technology ATSAMD10-based STEMMA soil moisture sensor
- Bosch BME280 temperature and humidity sensor
- DFRobot SEN0249 soil pH sensor
- DFRobot MG-811 CO2 sensor
Bill of Material (BOM)
Table 1 lists the bill of materials (BOM). Alternatively, you can grab all the parts you need from the preloaded shopping cart at Mouser.com.