Improving yield, soil health and input efficiency in rotational no-till systems
Results of a multi-year trial in Brazil (2019-2023)
Results of a multi-year trial in Brazil (2019-2023)
Between 2019 and 2023, Caires et al. (2025) and State University of Ponta Grossa (UEPG) conducted a long-term field trial in the Parana State of Brazil, within a typical maize-wheat-soybean rotation. The study evaluated POLY4 against standard potassium and sulphur sources, muriate of potash (MOP) and elemental sulphur (ES), with and without lime applications.
Field trial site | Ponta Grossa, Parana State, Brazil |
|---|---|
Trial years | 2019–2023 |
Conditions | Acid oxisol, no-till system |
Crop sequence | Black oat, corn, wheat, soybean (2 cycles) |
Experimental design | RCBD, 4 replicates, 2×4 factorial |
Treatments | with / without liming X (1) no-K control, (2) MOP, (3) MOP + ES, (4) POLY4 |
Application rates | MOP and POLY4 treatments received equivalent K rates of 300 kg K₂O/ha (first cycle) and 340 kg K₂O/ha (second cycle), applied in 3 splits across maize, wheat and soybean. MOP + ES and POLY4 treatments were also balanced for S. |
In this trial, POLY4 delivered significant benefits in grain yield and biomass production, and proved to be an effective substitute for lime, MOP and additional sulphur applications, while maintaining comparable agronomic performance.
Highest grain yield and biomass production with POLY4
Treatment | Grain yield (t/ha) | Above-ground C input (t/ha) | Root C input (t/ha) | Biomass input (t/ha) |
|---|---|---|---|---|
no-K control | 30.2c | 15.3c | 3.3c | 18.6c |
MOP | 38.2b | 18.9b | 4.1b | 23.0b |
MOP + ES | 39.2b | 19.5ab | 4.3ab | 23.8ab |
POLY4 | 41.3a | 20.4a | 4.4a | 24.8a |
Letters in the columns indicate significant differences by the LSD test (P ≤ 0.05) | ||||
Similar grain yield and biomass compared to combined lime + MOP + ES treatment
Treatment | Grain yield | Biomass-C input | ||
|---|---|---|---|---|
without liming | with liming | without liming | with liming | |
No-K control | 29.1c | 31.4b | 17.8c | 19.4b |
MOP | 37.4b | 39.0a | 22.5b | 23.6a |
MOP + ES | 37.0b | 41.3a | 22.8b | 24.9a |
POLY4 | 41.8a | 40.8a | 25.2a | 24.4a |
Letters in the columns indicate significant differences by the LSD test (P ≤ 0.05) | ||||
The results indicate that POLY4 can replace three separate crop inputs (lime, MOP, and ES) with a single solution, helping to simplify fertiliser logistics and enable efficient one-pass application in the field.
In no-till systems, the higher grain and biomass yields achieved with POLY4 can support a cycle of improved soil health and long-term productivity.
Caires et al. (2025) ‘Surface liming and fertilization with granulated polyhalite for crop grain production under a no-till cropping system’, poster presented at XX International Plant Nutrition Colloquium (IPNC 2025), Porto, Portugal, 22–25 July
Aerial photo of the trial plots
Maize crop. MOP + ES without lime
Maize crop. MOP + ES with lime
Maize crop. POLY4 without lime
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