China's land has become more productive and ecologically resilient over the past three decades, according to a sweeping "health check-up" of the nation's soil published by the China Geological Survey of the Ministry of Natural Resources.

The recently published National Land Geochemical Monitoring Report 2025 analyzed more than 500,000 national-scale land geochemical monitoring data records from 1995 to 2023, and revealed that nearly 30 years of conservation efforts have physically changed the makeup of the ground.

"National land geochemical comprehensive analysis reveals that, in 2023, 92.6 percent of land areas were rated as medium grade or above — an increase of 0.4 percentage points compared to 1995," said Peng Min, a researcher at the China Geological Survey who led the study.

Peng said the country's continued implementation of major ecological protection and restoration projects, including the Three-North Shelterbelt Forest Program, the conversion of farmland back to forests and the promotion of water-saving technologies, likely contributed to the improvement.

A key finding of the report is the stability of the soil's "skeleton" elements like silicon, aluminum, iron and magnesium. These minerals form the physical structure of the earth. When these elements are depleted or unnaturally high, Peng said, the land can "break", leading to desertification or it turning so salty (salinization) that nothing can grow.

The stability of this skeleton proves the physical foundation of China's land has remained largely intact despite decades of intensive use, he added.

During the 28-year monitoring period, levels of essential macronutrients for plant growth — such as nitrogen, phosphorus and potassium — as well as key micronutrients for plants and human health, including manganese, selenium and iodine, increased slightly. These elements are critical for crop yield and nutritional quality, and their moderate rise suggests a positive impact on food security and human health, Peng said.

One of the most significant improvements was the rise in "organic carbon", which increased from 6.7 to 7.8 grams per kilogram of soil between 1995 and 2023.

Organic carbon acts like a natural sponge and a magnet; it helps the ground hold onto water during droughts and prevents expensive fertilizers from being washed away into rivers during heavy rain. Peng said that higher organic carbon content contributes to a virtuous cycle through carbon sequestration driven by plant photosynthesis.

The most dramatic change occurred on the Qinghai-Tibet Plateau, where organic carbon levels surged by over 141 percent. This high-altitude region is acting as a massive "carbon sink", absorbing greenhouse gases at an accelerated rate.

Researchers credit this to a "warming and wetting" climate trend in the region, combined with smarter grazing practices that allow the delicate alpine grass to recover and trap more carbon.

Cheng Hangxin, another researcher at the China Geological Survey, said the increase suggests continued ecological improvement on the plateau.

He added that, as a major global carbon sink, the plateau absorbs significant amounts of carbon dioxide and is playing a growing role in mitigating the greenhouse effect.

As China moves into its next development phase during the 15th Five-Year Plan (2026–30), the "check-up" will become even more precise, according to Peng.

"The China Geological Survey will establish higher-resolution monitoring in key agricultural areas, with an additional 6,000 monitoring sites planned for this year," he said. "We will continue the monitoring project, aiming to conduct a national-scale survey every 10 years and a regional-scale survey every five years."

limenghan@chinadaily.com.cn