Commercial Soil
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C 1292-03
Biochar Basics: Effects on Plant Disease
Additional author: Mengmeng Gu, Professor, Colorado State University Department of Horticulture and Landscape Architecture.
How does biochar play a role in a plant-disease system? Briefly, before the pathogen infects plants, biochar can improve plant growth by increasing water and nutrient uptake, a healthier plant may be more resistant to attack. On the other hand, after a pathogen infects the plants, biochar could absorb the toxins, enzymes, and other compounds produced by pathogens.
Certain types of biochar could contain chemical compounds which is bad for pathogen growth. When incorporating this biochar into the substrate, the growth environment may become toxic to pathogens, so they cannot grow well enough to attack plants. For instance, eucalyptus biochar water extracts were found to inhibit Pythium growth in a lab setting. This finding indicates that substrate containing certain chemical extracts may impede plant infection by inhibiting the growth of Pythium (Bonanomi et al., 2015). After a pathogen infects a plant, biochar’s porous structure can absorb the toxins, enzymes, and other compounds produced by pathogens. Many types of biochar can improve plant growth, making the host plant stronger to fight against pathogens, thus reducing disease occurrence.|
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Additional author: Mengmeng Gu, Professor, Colorado State University Department of Horticulture and Landscape Architecture.
Container substrates must fulfill several functions for plant growth: create a suitable environment for root growth, physically support them, hold nutrients and water, and enable gas exchange between the roots and the atmosphere. Suitable physical and chemical container substrates’ properties facilitate these functions.
The physical properties of container substrates include air space (%), container capacity (%), total porosity (%), bulk density (g/cm3), and water holding capacity. Air space measures the proportion of air-filled large pores (macrospores) after drainage. Air space influences gas exchange and water holding capacity. Container capacity measures the maximum percentage volume of water a substrate can hold after drainage. Total porosity equals container capacity plus air space, and it measures the substrate volume that holds water and air. Bulk density measures how much one unit of the substrate weighs. Water holding capacity measures the container substrate’s ability to physically hold water against gravity; its maximum value equals container capacity.
Biochar can be derived from various feedstocks, processed under different pyrolysis temperatures, and subjected to various pre- or posttreatments, which can lead to dissimilar physical properties that affect the container substrate’s physical properties. Adding biochar may affect air space, container capacity, total porosity, and bulk density with variable effects. For instance, substituting peat moss with 50% green waste biochar (by volume) did not affect total porosity and container capacity, but significantly decreased air space, which was still in the optimal range (15%–30%) for container substrates. Similarly, a peat-moss-based substrate’s total porosity decreased with the increased addition of pelleted biochar. However, adding deinking sludge biochar increased the total porosity and air space of the container substrate.|
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Your goal as a greenhouse grower is to maintain a stable pH over the life of the crop. This is not an easy task since many factors can affect pH in the growing substrate. The pH can go up or down within several weeks of the crop cycle and if you wait for deficiency or toxicity symptoms to develop, you have already compromised the health of the crop and you r profits. Knowing all factors involved is the first step to managing the substrate pH.
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Whether from a local store, regional supplier, or another farmer down the road, understanding where your soil amendments come from and how they were handled prior to reaching your farm or garden is necessary to ensure you are sourcing the highest quality product with the lowest amount of risk.
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This publication highlights the role of selenium in animal nutrition; selenium concentration and distribution in soils and feedstuffs (grains and forages) produced in various parts of the United States and in Georgia; disorders resulting from Selenium deficiency or toxicity; various methods of selenium supplementation; and recommendations for selenium management in Georgia. This publication is intended to serve as an educational resource for university researchers and Extension specialists, county Extension agents and livestock, forage and feed producers, among others.
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Farmers have known for centuries that animal manures spread on pastures and cropland can improve soil fertility. In the 1920s, farmers began to use sludge from municipal wastewater treatment plants as a fertilizer. Through decades of research, the scientific and agricultural communities have come to understand that municipal sludge or “biosolids” contain valuable nutrients and organic matter that improve the soil in a way similar to animal manures. It is important to understand that biosolids are not raw sewage. Biosolids are organic solids that have been treated to stabilize organic matter and reduce disease-causing organisms or pathogens.
This resource was developed to help answer some common questions regarding the use of biosolids and to give farmers benchmarks for good practices.|
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Conservation tillage with agronomic crops (i.e., cotton, corn, soybeans, etc.) has been successful in Georgia production. Such production practices have several benefits, the most notable being the elimination of soil erosion. Other benefits include but aren’t limited to increases in soil organic matter, maintaining a healthy rhizosphere (root-zone soil), reduction of riparian and waterway pollution, and water conservation.
Some examples of conservation tillage practices include no till, ridge till, and strip till. No–till production involves no tillage of field soils and leaves all of the previous crop residue on the soil surface. Ridge–till production involves building a ridge during cultivation, then scalping the ridge and sowing seed. The scalping process moves most of the previous–crop residue to the row middles, leaving a clean row for sowing. Strip–till production is when a narrow strip is tilled for each row that will be planted, leaving the row middles intact with the previous–crop residue. Strip–tillage may reduce yields if weeds in the untilled area are not killed, as these weeds will compete with the crop for water and nutrients. Although the planted row is free of previous crop residue, it may be advantageous to kill the cover crop to prevent it from competing for nutrients and water with the vegetable crop.
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This publication discusses the use of scrap wallboard at residential construction sites.
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Soil pH is one of the most important measurements of soil fertility. Knowing a soil’s pH may help in diagnosing nutritional problems of agricultural crops and other plants.
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