Agricultural productivity in arid regions is frequently limited by a lack of fresh water, forcing farmers to rely on brackish water for irrigation. This practice leads to salt accumulation in the soil, which stunts crop growth and damages plant health through toxic ion buildup. A recent study in the journal Horticulturae by authors Guili Liu and colleagues investigated how adding peat or biochar to the soil can protect Cherry Belle radishes from these harsh conditions. The researchers discovered that these amendments not only improve the quality of the soil but also significantly enhance the plants’ ability to survive and thrive despite being watered with salty water.

The findings indicate that peat is particularly effective at managing soil chemistry, as it significantly reduced soil salinity by 42.61% and lowered the pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More level. Biochar also provided substantial benefits by reducing soil salinity by 32.44%, though it tended to slightly increase the soil’s alkalinity. Both materials acted as a buffer, preventing the salt from reaching levels that would typically kill or severely stunt the radish plants. This physical and chemical improvement of the soil creates a much more hospitable environment for sensitive vegetable crops.

Beyond soil improvement, the study highlighted dramatic boosts in plant growth and biological function. When soil was treated with 5% peat, the weight of the radish roots increased by 74.40% compared to plants grown in untreated salty soil. Similarly, a 3% addition of biochar resulted in a 50.27% increase in root weight. These growth improvements are directly linked to better photosynthesis; the rate at which the plants processed carbon dioxide increased by approximately 89% with peat and 86% with biochar. This suggests that the amendments allow the plants to maintain their energy production systems even under high-stress conditions.

The research also looked at how these materials protect plants on a cellular level. Salt stress usually causes the production of harmful molecules that damage plant cell membranes, but peat and biochar reduced this internal damage by roughly 41%. Furthermore, the amendments helped the radishes maintain a proper internal balance of minerals, specifically increasing the ratio of healthy potassium to toxic sodium by over 90% in some cases. By stabilizing these internal processes, the amendments prevent the “oxidative stress” that typically causes plants to wither in salty environments.

While both materials showed positive results, the study noted that their effectiveness depends on the amount used. For peat, a 5% concentration generally provided the best results across all categories. In contrast, biochar was most effective at a 3% concentration, with higher amounts actually becoming less helpful. This dosage-dependent relationship is crucial for farmers to understand to avoid wasting materials or accidentally harming their crops. The researchers concluded that using these soil amendments provides a safe and effective way to use low-quality water for high-quality food production.

Source: Liu, G., Zhou, Y., Zhu, H., Qi, Y., Jia, Y., Xu, H., Sun, X., & Zheng, B. (2026). Application of peat or biochar on Raphanus sativus L. ‘Cherry Belle’ under brackish water irrigation: Its effect on growth and salt tolerance. Horticulturae, 12(248).