Christophe's Compost Corner: Weekly Update August 1

  Farmer Al and his assistant Marlene are already harvesting the tomatoes, peppers and vegetables in the one acre plot of land we have leased from a neighbor. On the compost side, we have been concentrating on preparing vermicompost and vermicompost teas tailored to the growth of tomatoes and vegetables. Tomatoes grow best (especially at the fruiting stage) in soils that tend be fungal (a fungal to bacterial ratio close to one).  Peppers and some vegetables grow in more bacterial soils (F:B ratios between 0.30-0.5). Let’s not forget that all good composts contain beneficial fungi, bacteria, protozoa, nematodes and other inhabitants of the soil food web: only the proportions change from one compost pile to another. The optimum pH range for the growth of all these plants is between 6.2-6.8.

  One of the Frog Hollow worm beds (100 ft X 5 ft X 1 ft) produced 8 tons of vermicompost this year. This bed had an F:B ratio equal to 0.35 (the fungi and bacteria were in a range that characterizes a good compost). The beneficial protozoa were abundant and diverse. The numbers of beneficial nematodes were significant but low. The pH of the compost was ideal for tomatoes, peppers and vegetables (pH 6.5). The water holding capacity was in a very good range. This vermicompost can be used around vegetables without any adjustments. It can be made more fungal by adding a small amount of humic acids and it can be used around tomatoes.

  Vermicompost teas can be made from the compost described to increase the microbial population in the soil around the plants and to control some diseases.

  Our goal is to increase the water holding capacity of the soil around the plants described in order to use as little water as possible.  Also, since the water supply can be uneven (especially due to drought restrictions), a well-balanced compost should control the flow of macronutrients to the plants. Calcium is one macronutrient that is usually not deficient in California soils but can cause physiological problems in plants when it is not transported efficiently within plants. Blossom-end rot on tomatoes, chili peppers, aubergines is caused by inadequate calcium associated with unevenness in the water supply that interrupts the flow of calcium (occasionally calcium may be inaccessible in soils that contain large proportions of clay). Blossom end rot appears as a dark-blackish patch at the end of the fruit that had the flower. Blossom end rot is caused by a calcium deficiency in the fruits. Calcium deficiency reduces cell permeability and causes swelling followed by leakage. This is not a bacterial or fungal problem but strictly a mineral problem. Most of the time, the patch can be removed from the end of the fruit and the rest of the fruit is tasty.

  Calcium is an essential macronutrient that influences the productivity of all agricultural ecosystems. Macronutrients are defined as mineral elements used in greatest quantities by plants.  For animals, the calcium content of plants is important because it is a major component of bones and teeth and plays important roles in many physiological processes (cell communication). It has been suggested that the relatively higher calcium content of soils in Africa could account for the occurrence of large herbivores such as elephants, zebras and giraffes in semi-arid savannas but not in South America (N.C. Brady, 2010).

  Are fruits and vegetables trying to kill you? In a way they are trying but in fact this actually toughens up our immune system. Enjoy reading the following article by M. Velasquez-Manoff

Author: Christophe Kreis MLF Soil Consulting PhD, Molecular Biology/Developmental Biology, University of British Columbia, Canada. Christophe is co-founder of MLF Soil Consulting with his wife Monique. He started his career in basic medical research and after various positions in academia and industry Christophe slowly returned to his first passion Soil Ecology and Microbiology. It is his belief that human health is tied intimately to soil health through the production of healthy food. For this reason MLF Soil Consulting is committed to help farmers improve the management of their soil through composting, vermicomposting and biological analysis of microbial soil life.


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