Wang Guiman's speech on black soil protection drew warm applause at the Northeast China Economic and Trade Promotion Event on Monday in Changchun, Jilin province.

The event's theme was "striving for new breakthroughs in the full revitalization of Northeast China". It attracted over 200 political party leaders, foreign diplomatic envoys and representatives of foreign business communities in China from more than 50 countries and regions.

Wang, director of Lishu county's agricultural technology extension station, drew comparisons between the land using the Lishu model and traditional farming over the past 15 years.

"It's evident that the land using the Lishu model has darkened, the root mass has increased and the organic matter in the soil has risen from 1.7 to 3.4 percent, resulting in better soil and increased grain production," he said. "The yield per hectare in the areas using the Lishu model has reached over 16,500 kilograms while neighboring plots without the model typically yield around 10,500 kg."

He added that Jilin would welcome a bountiful harvest with a historic grain output this year.

Jilin is an important national grain producer and one of the main locations of black soil, which is rich in organic matter and ideal for growing crops.

According to data from the National Plan for Soil and Water Conservation (2015-30), 109 million hectares of the soil, including around 29 million hectares of farmland, are in the northeast region of China, spanning the provinces of Heilongjiang, Jilin, Liaoning and the eastern part of the Inner Mongolia autonomous region.

According to the Guideline on Protecting Black Soil in Northeast China (2017-30), excessive exploitation in recent decades has resulted in the erosion of black soil, threatening biological diversity and sustainable food production.

Long-term farming and the overuse of fertilizers and pesticides have destroyed the soil's micro-ecosystem, and expanded rice cultivation has depleted underground water reserves.

In 2009, China Agricultural University professor Li Baoguo and his students established a black soil protection workstation in Lishu.

After years of research and cooperation with the Chinese Academy of Sciences and the county's agricultural technology station, they devised a unique model of conservation farming.

Wang said that one key to conservation farming is to plow less frequently by adopting no-tillage and stalk mulching practices.

"In the past, farmers usually plowed the land three or four times when they planted maize, which can destroy the structure of black soil layers. Now, with mechanized planting, the processes of making straw, ditches, fertilizing, sowing and covering can be completed simultaneously," he said.

"The reduction of rolling compaction as the result of using agricultural machines can help improve the soil's water percolating capacity, and maize straw returns potassium and nitrogen to the earth," he said.

The Jilin government began to promote the Lishu model across the province in 2012.

"During the process, we have gradually figured out some good methods in practice," he said. "While establishing demonstration bases, we communicated with farmers, helping them understand, agree with, and apply the Lishu model."

"Additionally, we have developed tailored protection models for different soil conditions in plain areas, hilly areas, sandy areas, and saline-alkali soil areas," he said. "Currently, the experience of the Lishu model has been promoted not only in the northeastern regions but also nationwide."

"The black soil in Northeast China has played an essential role in the major grain-producing region," he said. "We are full of confidence in continuously safeguarding national food security."

"As an agricultural science and technology worker, I will continue my work to protect the land," he added.

Han Junhong contributed to the story.