The Biosphere Blog

Availability to Plants Zinc is found in very small amounts in soil, usually from 10 – 300 ppm (parts per million), and mostly in rock minerals. The Zn2+ ion can in fact replace Fe2+ and Mg2+ ions in minerals. Zinc can also be found on the exchange sites… more »

Last week’s discussion on iron became very ‘chemical’ very quickly with quite a crash-course on oxidation, reduction and oxidation numbers thrown in out of nowhere! I do appreciate that it would have been heavy going for people without… more »

Just as there are six macronutrients, so are there six micronutrients: iron (Fe), manganese (Mn), boron (B), zinc (Zn), copper (Cu), and moybdenum (Mo). Micronutrients are so named as they are needed in smaller amounts than the macronutrients. As they… more »

Magnesium (Mg) in soil ranges from about 0.05% in sandy soils up to 0.5% in clay soils. It is more prevalent in clay soils as these contain very weatherable magnesium-containing minerals. Some clay minerals themselves contain magnesium. Magnesium may… more »

Elemental calcium (Ca) makes up 3.64% of the Earth’s crust, making it the fifth most common element in the crust after oxygen (O), silicon (Si), aluminium (Al) and iron (Fe). This makes it the most abundant of all plant nutrients after oxygen and… more »

So far we’ve covered he big three macronutrients: nitrogen (N), phosphorus (P), and potassium (K) — the famous NPK. Today we’ll cover a lesser-known, but also important nutrient for plants: sulfur (S). It may surprise you that sulfur is an… more »

Of the six essential macronutrients a plant needs, the big three are nitrogen (N), potassium (K), and phosphorus (P), our subject for today. Availability to Plants Elemental phosphorus (P) makes up 0.02–0.15% of soil, and primarily exists as hydrogen… more »

Last week we explored why nitrogen is an essential macronutrient in plants, by looking at the molecules it appears in, and the biochemical processes relying on those molecules. From that we could better understand where and why nitrogen deficiencies and… more »

Macronutrients are those a plant requires in high concentrations. There are six of these: nitrogen (N), potassium (K), phosphorus (P), magnesium (Mg), calcium (Ca), and sulfur (S). Plants receive these nutrients either as standalone ions or as part of… more »

Nitrogen drawdown is the loss of nitrogen to plants in the presence of high amounts of carbon, resulting in slower growth and in extreme cases, deficiencies. Drawdown occurs when large amounts of high-carbon materials such as sawdust or wood chip are… more »

So far we’ve covered two essentials for life: water (for its flowing and carrying properties over a wide temperature range), and photosynthesis (for turning light energy into food which then flows up the food chain in an ecosystem). But no… more »

This post complements this earlier one as today I discovered a third ladybird/bug/beetle species enjoying a flower! Here is the minute two-spotted ladybird/ladybug/ladybeetle, officially known as Diomus notescens. And it really is minute, being just 2.5… more »

Update: 5th October 2023 Much thanks to entomologist Katherine Rawson for her help in identifying the ant species in this post to at least the genus level — very much appreciated! Pollinators are essential to many flowering plants’ reproduction. A… more »

This earlier post lists the most important nutrients plants require to grow, flower and fruit. But barring a full laboratory soil or leaf analysis, most people only become aware of any deficiencies when their trees show poor growth and development. By… more »

Have you ever repotted a plant and wondered why the bottom of the potting mix is so incredibly saturated compared to the rest, despite the drainage holes at the bottom of the pot? You may have thought this was a sign of over-watering, but what you… more »