Compost and soil amendments on sandy, low-organic-matter soil
Quick answer
Compost is a weak fertiliser and a valuable soil amendment. Its nutrient content is roughly a tenth of a mineral product's and varies with whatever it was made from, so it is a poor way to correct a specific shortage. Its real contribution on arid sandy soil is organic matter — which raises the soil's ability to hold nutrients at all.
What compost contains
FAO defines compost as an organic manure produced by aerobic, anaerobic or partially aerobic decomposition of crop, animal, human and industrial wastes; prepared with earthworms it is vermicompost. Typical figures: rural compost about 0.5% N, 0.2% P₂O₅, 0.5% K₂O; urban compost about 1.5%, 1.0%, 1.5%. On average also about 10 ppm zinc, 6 ppm boron, 12 ppm manganese.
The caveat matters as much as the figures: nutrient status depends largely on the nutrient content of the wastes composted. Those numbers describe what FAO reports as typical, not what any particular batch holds.
Why the structural role matters more here
FAO's problem list for arid soils includes low to very low organic matter content, low content of available and mobilizable nitrogen, and low storage capacity for mineral nutrients in sandy soils. Organic matter addresses the third directly: soils rich in organic matter have a higher CEC than soils low in it, and CEC is what keeps nutrients within reach instead of letting them leach.
FAO also notes organic substances can mobilise nutrients from soil mineral reserves through organic acids and chelating substances excreted by roots and microbes.
The nitrogen tie-up to expect
Material that is not fully decomposed can temporarily reduce available nitrogen. FAO records that short-term fixation of nitrogen, phosphorus and sulphur into micro-organisms may create a transient deficiency, particularly at wide ratios of carbon to these elements. A plant that yellows shortly after a heavy dressing of coarse material may be showing exactly this.
In Kuwait's conditions
The case for organic matter here is strong precisely because the baseline is so low. But two cautions apply. First, high temperatures accelerate the breakdown of organic matter, so additions are not permanent and the effect needs maintaining. Second, any amendment applied to a salt-affected soil should be considered alongside its own salt content — a soil analysis before and a water analysis alongside are the sensible precaution.
General arid-region guidance, not a Kuwait measurement. No application rate per square metre is given, because that depends on your soil analysis and the material.
Common mistakes
- Using compost to correct an acute deficiency.
- Assuming a batch's nutrient content from its description.
- Applying material that has not finished decomposing, then blaming the resulting yellowing on hunger.
- Piling amendment against stems and trunks.
- Treating one application as permanent.
Boundary
No quantity per square metre, no depth, no product and no amendment rate is given. FAO's typical analyses are quoted as reported values, not as what your material contains — only an analysis of that material tells you that. Gypsum and other salinity amendments are outside this guide and need a soil analysis and specialist sign-off.
Related glossary terms
Sources
- FAO — Fertilizer and Plant Nutrition Bulletin 16, Chapters 3, 4 and 5, and Glossary.
Accessed 26 August 2026. Last reviewed: 27 August 2026.