Which of the following is NOT considered a benefit of using green manures?

Green manures are cover crops that are grown primarily to improve soil health and productivity when they are plowed back into the soil. The primary benefits include improving soil structure, enhancing nutrient retention, and adding organic matter to the soil.

Improving soil structure is an essential benefit of green manures as they help to create a more porous soil, which can enhance root growth and water infiltration. The inclusion of green manures also enhances nutrient retention by capturing and holding nutrients in the soil, making them available for subsequent crops. Additionally, green manures contribute organic matter when they decompose, which is vital for maintaining soil fertility and promoting a healthy soil ecosystem.

The presence of green manures in the soil does not increase accumulated salt levels. Instead, they typically help to mitigate salinity issues by improving drainage and encouraging a more balanced nutrient profile. Therefore, identifying increased accumulated salt levels in the soil as a benefit is incorrect, making it the answer to this question.