April 2026
The 60% problem — and what to do about it.
According to the Fertilizer Association of South Africa, only about 40% of fertilizer applied to commercial crops is absorbed by the plant. The other 60% is lost — leached down through the soil profile, volatilised into the atmosphere as gas, or washed off the surface in the next rainstorm.
That number gets repeated in industry circles often enough to feel abstract. But translate it: every R10 a farmer spends on fertilizer, R6 doesn't reach the crop. At commercial scale, that's millions of rand of nutrient leaving the farm before it's done any work.
The losses aren't random. They scale with depleted soil. The less organic carbon and biological activity the soil has, the less it can hold and cycle the nutrients you apply. Healthy, carbon-rich soil retains nutrients in the root zone where the plant can find them. Depleted soil acts like a sieve.
Bio-based fertilizer addresses this directly: by making carbon part of every pellet, application becomes a soil-building event in addition to a nutrient delivery. Over seasons, the soil becomes more efficient at retaining what you give it. The 60% problem doesn't disappear, but it shrinks.
Source: FERTASA technical bulletins.
March 2026
Reading a soil test — what to ask for, what to look for.
Most agricultural soil tests cover the same handful of parameters — pH, electrical conductivity, the major nutrients (N, P, K), and sometimes secondary nutrients (Ca, Mg, S) and micronutrients. If you're new to soil testing, here's what each tells you and what to actually do with the result.
pH controls how available every other nutrient is to the plant. Most cash crops want pH 5.5–6.5. Outside that range, even fully fertilised soil can starve a plant — the nutrients are present but locked.
Electrical conductivity (EC) is a proxy for total dissolved salts, which can damage plant roots at high levels. Common in over-fertilised or dryland soils.
Soil organic carbon (SOC) is rarely on a basic test but worth requesting. It's the single best indicator of long-term soil health. Below 1% SOC, most soils struggle. Above 2%, biology and structure are usually working in your favour.
N-P-K levels tell you what's there, but not what's plant-available. A soil rich in phosphorus on a test can still produce a P-deficient crop if the pH is wrong or the biology is dead.
The most useful soil tests come with a recommendation: how to amend the soil and what to fertilise with. Always request that — without it, you have a chemistry report but no action to take.
February 2026
What "carbon carrier" actually means in a fertilizer pellet.
Open a bag of conventional NPK fertilizer and you'll see uniform granules. They look like the active ingredient. They're not. They're roughly half something else: filler.
The filler is whatever inert material the manufacturer uses to hold the nutrient compounds in a deliverable physical form. It's typically sand, clay, limestone, or a chemical bulking agent. Once it hits the soil, it dissolves or breaks up — but it doesn't do anything biologically. Its only job is to bulk the pellet.
A carbon carrier is the same role played by a different material. Sapling's carrier is high-carbon organic material — biologically active matter that, once it breaks down in the soil, feeds microbes, contributes to soil organic carbon, and improves structure. The chemical NPK still does what NPK does. But the half of the pellet that used to be inert filler is now also doing work.
This is why "bio-based fertilizer" isn't the same as "organic fertilizer." The nutrients are conventional. Only the carrier is different.
