Somewhat hairy and produce roots at their joints. Its paired leaves usually differ in size. Its greenish or greenish-yellow flowers are grouped together in small clusters (8-12 mm long) in the leaf forks. Some of the flower parts become hardened and form sharp prickles as they mature.
As A Soil Indicator:
ow calcium, High manganese. High Magnesium, High Iron, High Zinc, High Boron, High Chloride, Little organic matter, anaerobic soil conditions, high moisture content, compacted, pour drainage
Annual stems, perennial rootstock. Seeds germinate in spring and summer after rain and produce creeping stems and a stout rootstock over summer. Stems take root at the nodes forming a dense mat. Flowering occurs from March to April and the top growth dies in winter. New shoots emerge from the rootstock in spring.
Fodder plant, moderately palatable when young.
Forms competitive dense mats with prickly burrs that may injure the feet and mouths of stock and dogs. Readily dispersed by adhering to stock and tyres. Weed of Lucerne, orchards, turf, recreational areas, sale-yards, pastures, cultivated areas and roadsides.
May cause hay fever, dermatitis and asthma in some people. Toxic to stock but not usually eaten. Sheep will graze young plants without any apparent ill effect. Causes a skin ailment in cattle.
Burr Medic is a low-growing, almost hairless, sprawling herb with leaves divided into 3 heart-shaped leaflets. The terminal leaflet is on a longer stalk than the two side leaflets. It has clusters of 2-7, small, yellow, pea-type flowers with petals. The fruit is a small, greenish-brown burr with 1-6 tight coils that are often spiny.
As A Soil Indicator:
Low Calcium, Low Phosphorus, High bacterial activity, More abundant on heavy alkaline soils.
Annual. Germinates in autumn to winter and produces large amounts of palatable herbage in winter and spring. Flowers in spring and dies with the onset of summer drought and high temperatures.
Important pasture species especially on the heavy alkaline soils.
Produces good quantities of palatable fodder over the winter to spring period.
Burrs provide a protein supplement over summer. Fixes nitrogen. Nectary plant.
Considered a weed of crops, gardens, lawns, recreational areas and disturbed areas
Occasionally toxic causing photo sensitisation, clover sickness in sheep, cattle horses and pigs. Lambs including newly born ones are most affected. Mainly occurs on luxuriant growth during sunny weather in spring. May cause bloat in cattle..
Native to North America, Ragweed is a fern-like plant that is detrimental to the environment. Fast-growing, the weed often hampers agricultural, Ragweed grows between 1 to 2m in height. It features a flower spike up to 20cm long with yellow flowers when mature and small, black seeds.
As A Soil Indicator:
Very low Calcium, Very high Potassium, Very low Phosphorus, High Magnesium, High Sulfate, Low Copper, Little organic matter, Compacted soils
Annual. Seeds germinate in August to October after rain and grow quickly. Flowering starts in late summer and continues to May. Plants die in winter. Produces an average 3000 seeds per year with some producing up to 62,000. Seeds won't germinate for some time after maturity. Exposure to light and alternating temperatures improves germination. Seeds become dormant with high temperatures and may survive for over 40 years.
Used to stop bleeding or as a cure for dyspepsia. Good forage value for quail and cattle but unpalatable to horses. The seeds produce an oil with good drying qualities that is potentially useful for paints and varnishes
Causes severe hay fever and dermatitis. Cattle eat young plants, but horses avoid it so that it often over-runs horse paddocks. It produces toxins that affect the growth of neighbouring plants.
Toxic. The unpleasant odour usually makes it distasteful to stock. It may cause a sore mouth in stock that graze it.Hay fever and skin irritations in people.
“Soil is the great connector of lives, the source and destination of all. It is the healer and the restorer, and the resurrector by which disease passes into health, age into youth, death into life. Without proper care for it, we can have no community, for, without proper care for it, we can have no life.” – Wendall Berry
Our relationship to the soil is absolute – It provides us with our food, building materials, medicine, filters our waters and stores carbon. It is composed of organic and inorganic material, gases, liquid and organisms that together support life.
But over the last 50 odd years, our soils have not been faring so well. Research has shown that the nutrient availability in our soils is declining and this, in turn, has had an effect on our food.
Dr David Thomas provides a comprehensive analysis of historical changes in food nutrient levels.
By comparing data available from 1940 with that in 1991, Thomas was able to show a substantial loss in mineral and trace element content in every group of foods investigated.
Mineral depletion in vegetables 1940 - 1991
Average of 27 kinds of vegetables
Mineral depletion in meat 1940 - 1991
Average of 10 kinds of meat
The nutrient depletion summarized in Thomas’s review represents an average of mineral and trace element changes in 27 kinds of vegetables and 10 types of meat.
With this in mind, understanding how the minerals in the soil affect the plants we eat is critical from the macro nutrients to the ever essential micro nutrients. What functions does that mineral form in the plant, how can we assess the plants to see what they are deficient in, what are the conditions that can attribute to this reduction in nutrient availability, and typically, what crops may be affected. The information provided below can help show the relationship between the different minerals in our soils and the effects they have on our plants and in turn, us.
Some nutrient is also moves more freely than others
Nutrient mobility in soil
Very Mobile – (prone to leaching) nitrate Nitrogen, sulfate Sulfur, Boron
Moderately Mobile – ammonium Nitrogen ( ammonium Nitrogen is temporarily immobile), Potassium, Calcium, Magnesium, Molybdenum
Immobile – organic Nitrogen, Phosphorus, Copper, Iron, Manganese, Zinc (Chelated forms of Copper, Iron, Manganese and Zinc are mobile and resistant to leaching)
Nutrient mobility in plants
Very mobile – Nitrogen, Phosphorus, Potassium, Magnesium (Deficiency symptoms appear first in older leaves and quickly spread throughout the plant)
Moderately mobile – Sulfur, Copper, Iron, Manganese, Molybdenum, Zinc (Deficiency symptoms first appear in new growth but do not readily translocate to old growth)
Immobile – Boron, Calcium (Calcium is very immobile)
SOIL ANTAGONISM AND INTERACTION CHART
When high levels of Nitrogen induce accelerated growth rates, levels of micro nutrients that would normally be marginal can become deficient. High soil levels of Nitrogen can assist Phosphorus, Calcium, Boron, Iron and Zinc but an excess can dilute these elements. Low soil levels can reduce Phosphorus, Calcium, Boron, Iron and Zinc uptake. Ammonium Nitrogen can make Molybdenum deficiency appear less obvious.
High levels of Phosphorus reduce Zinc and, to a lesser degree, Calcium uptake. It is antagonistic to Boron in low pH soils.
High levels of Potassium reduce Magnesium and to lesser extent Calcium, Iron, Copper, Manganese and Zinc uptake. Boron levels can either be low or toxic. Low levels can accentuate Iron deficiency.
High levels of Calcium can accentuate Boron deficiency. Liming can decrease the uptake of Boron, Copper, Iron, Manganese and Zinc by raising soil pH.
High levels of Copper can accentuate Molybdenum and to a lesser degree Iron, Manganese and Zinc deficiency.
Iron deficiency can be accentuated by liming, low Potassium levels or high levels of Copper, Manganese or Zinc.
High levels of Copper, Iron or Zinc can accentuate Manganese deficiency – especially repeated soil applications of Iron. Uptake can be decreased by liming or increased by Sulfur applications (because of the affects on pH)
Deficiencies can be accentuated by high levels of Copper and to a lesser degree Manganese. Uptake can be adversely affected by sulfates. Uptake can be increased by phosphates and liming. Molybdenum can increase Copper deficiencies in animals.
Uptake can be decreased by high Phosphorus levels, liming or high levels of Copper, Iron or Manganese. Zinc deficiencies are often associated with Manganese deficiencies, especially in citrus.
A delicate annual herb, with small, paired, egg shaped, pointed-tip leaves on long, round, weak stems that have a line of hairs between the nodes. It has small white flowers with 5 deeply notched petals that are shorter than the sepals
As A Soil Indicator:
Very low Calcium, Very low Potassium, Very high Phosphorus, High Magnesium, High Iron, High Sulfate, High Copper, High Zinc, High Boron, High Chloride, High Selenium, Little organic matter, Compacted soils,
Annual. Germinates anytime often with a main germination from autumn to spring. Flowers late-winter/spring
Used as a green salad or cooked vegetable. It has medicinal and therapeutic uses, is rich in vitamin C and may be eaten as a salad vegetable.
A very competitive plant in higher rainfall areas. It can accumulate nitrate and potentially become toxic to stock. In addition, it has a relatively high oxalic acid content and a low level of calcium that may have an adverse effect on dietary calcium bio-availability.
Buried seeds are known to retain viability for at least 25 and probably over 40 years. Seed buried in soil for 10 years gave up to 22% germination.
Not recorded as toxic