Northeast China's black soil long overburdened, degradation and loss problems growing increasingly serious
In the past “a chopstick stuck in the ground would sprout”; now “how come fertilizer is applied but grain still won't grow”
In Zihe Village, Erjing Town, Bei'an City, Heilongjiang Province, village party branch secretary Yan Zhongjie dug less than 30 cm with a shovel and exposed yellow earth. “The black soil layer has dropped from an average of 60 to 70 cm in the 1950s to the current average of 20 to 30 cm, and it continues to degrade every year.” Yan Zhongjie said.
A recent interview by the Economic Information Daily reporter in the Northeast black soil region found that due to long-term overloaded use and emphasis on exploitation over nurture, the deterioration and loss of black soil resources are showing a worsening trend.
Black soil grows thinner, losing 1 cm every year
Statistics from the Songliao Water Resources Commission of the Ministry of Water Resources show that the black soil layer of cultivated land in the Northeast Plain has dropped from 80 to 100 cm at the early stage of reclamation to 20 to 30 cm, with about 1 cm of black soil lost each year, while forming that thickness of black soil takes about three to four hundred years, meaning the loss rate is hundreds of times the soil formation rate.
Similar phenomena of thinning black soil layers and declining soil fertility in Zihe Village are not isolated cases in the Northeast. On June 24, the Ministry of Agriculture held a meeting in Harbin to advance and implement the Northeast black soil protection and utilization pilot project, with agricultural department heads from the four Northeast provinces (regions) attending. Yu Wenbo, inspector of the Jilin Provincial Agricultural Commission, said that in Jilin Province's black soil region, the average annual loss of topsoil can reach 0.3 to 0.7 cm, and the depth of the plow pan in cultivated land has dropped from about 20 cm in the 1980s to 13 cm. At the same time, the quantity and quality of organic matter in the plow layer have declined, with organic matter decreasing at an average annual rate of 0.1%, leading to degradation of soil biological characteristics and increased incidence of crop pests and diseases.
Arun Banner and Jalaid Banner, located at the southern foot of the Greater Khingan Mountains, are typical black soil areas. With rapid population growth, the land reclamation rate and soil use intensity have continuously increased, and the quality of black soil cultivated land shows a “three lows” situation. According to Jia Yuefeng, deputy director of the Inner Mongolia Autonomous Region Agriculture and Animal Husbandry Department, first, the ecological regulation capacity is low. In these two banners, the area of cultivated land with mild or above erosion accounts for 55.8% of the total cultivated land area, of which 19.7% of cultivated land has moderate or above erosion; within the region, the plow layer soil has become thinner, the surface is covered with gravel and gullies crisscross, and some cultivated land is on the verge of being abandoned. Second, the ability to resist natural disasters is low. In Arun Banner and Jalaid Banner, dry slope land accounts for 46.6%, and this is typical rain-fed agriculture with no irrigation conditions; dry land is prone to drought, and low-lying land is prone to waterlogging. Third, the comprehensive production capacity is low. In these two banners, part of the black soil layer thickness has decreased from 60 to 100 cm at the early stage of reclamation to 20 to 30 cm, and the plow layer thickness has dropped from 25 to 35 cm at the early stage of reclamation to 10 to 20 cm.
Tan Zhijuan, a researcher at the Qiqihar City Agricultural Technology Extension Center, said that the precious black soil has already shown problems such as thinning soil layers, reduced organic matter, and declining fertility. “In some major grain-producing areas, the black soil has changed from the early development period, when ‘if you squeeze a handful it drips oil’ and ‘a chopstick stuck in the ground would sprout,’ to today's ‘big sand piles, broken yellow skin, and how come fertilizer is applied but grain still won't grow.’”
The Northeast black soil region is one of the world's three major black soil belts, with a land area of 1.03 million sq km, of which cultivated land area is 450 million mu, accounting for 22.2% of the country's total cultivated land area. In recent years, the Northeast black soil region's total grain output has accounted for about 20% of the country's total, and commodity grain has accounted for more than 1/3 of the country's total, capable of meeting the grain supply for 50% of the country's urban population, holding an unshakable position in ensuring national food security.
Chen Mengshan, party secretary of the Chinese Academy of Agricultural Sciences, said that the prominent manifestations of Northeast black soil degradation are: soil organic matter decline and nutrient imbalance, meaning the soil has become thinner; shallower plow layers and soil compaction, meaning the soil has become harder; and in some areas water and soil erosion has formed erosion gullies, meaning the soil has become less. In recent years, the state has implemented projects such as high-standard farmland construction, soil testing and formulated fertilization, and conservation tillage. The trend of black soil resource degradation and loss has been slowed in some areas, but the overall deterioration has not been fundamentally reversed. Emphasis on exploitation over nurture; farming depends on chemical fertilizers to hold it up
Behind the black soil's “quantity decrease and quality decline,” in addition to natural causes such as many hilly and sloping areas, loose black soil surface layers, and severe water and wind erosion, it is also closely related to excessive reclamation and use, unreasonable farmland management and cultivation measures, and long-term neglect of soil and water conservation measures.
The Economic Information Daily reporter found that weak protection awareness, long-term predatory management, and emphasis on exploitation over nurture are the root causes of black soil degradation. Zeng Yande, director of the Planting Management Department of the Ministry of Agriculture, said that when the Great Northern Wilderness was developed, the purpose was to increase production capacity, but during many years of development, only development was emphasized and protection was not paid attention to. This can be seen from the difficulty of returning straw to the field. Although returning straw to the field is an important measure to build soil fertility, because straw collection is difficult and crushing costs are high, farmers are not very enthusiastic and often just burn it.
Lu Chang'ai, a researcher at the Institute of Agricultural Resources and Regional Planning of the Chinese Academy of Agricultural Sciences, said: “In the Northeast black soil region, about 60% to 95% of organic matter such as straw is burned, and very little is returned to the field, causing the organic matter content of the soil surface layer to drop from the original 8% to below 3%, and organic matter in the plow layer declines at an average annual rate of 1‰.”
Unreasonable planting systems also lead to the loss of fertile black soil. The reporter learned that in recent years, affected by planting returns, the soybean planting area has sharply decreased, and coupled with the influence of grain assessment indicators, the grain-soybean rotation system has been difficult to implement, so the nitrogen-fixing and soil-fertilizing role of soybeans has not been fully brought into play. At the same time, the development of planting and breeding is uncoordinated, the development of herbivorous animal husbandry lags, the proportion of corn converted into feed locally is low, and organic fertilizer resources are obviously insufficient. Heihe City in Heilongjiang Province is at a high latitude and is a traditional major wheat and soybean producing area in China. The reporter learned from the Heihe City Agriculture Bureau that in 2011 the corn area in Heihe City was more than 1.2 million mu, while this year it reached 5.5444 million mu. Local agricultural officials said that with corn planted continuously for many years, the original rotation system has been destroyed, leading to single consumption of soil nutrients and black soil loss.
Experts said that applying organic fertilizer and deep plowing and deep loosening can effectively protect black soil, but these are labor-intensive, time-consuming, and high in production cost. Although there are some subsidies, the beneficiary scope is narrow and the subsidy level is low, with insufficient incentives, so promotion and application are limited. In order to promote stable and increased grain production, farmers have no choice but to apply more chemical fertilizer. In recent years, chemical fertilizer input has increased year by year, and the popularization and application of small agricultural machinery have led to intensified soil hardening and compaction, thinner plow layers, and thicker, harder, and upward-moving plow pans, deteriorating cultivated land quality, reducing soil water storage capacity, and intensifying water and soil erosion.
Taking chemical fertilizer use as an example, farmers generally report that increased grain production mainly depends on chemical fertilizers. Although they know it will cause soil compaction, they still use it all the same. Liu Junli, a large rice grower in Fujin City, Heilongjiang Province, told the Economic Information Daily reporter that this year he planted more than 1,200 mu of rice and bought 40 tons of chemical fertilizer when preparing for spring plowing. “A few years ago, when farming my own contracted land, I applied twenty or thirty jin of fertilizer per mu, but now that the farming scale has expanded, in order to increase yield, I use about 70 jin per mu.” Liu Junli said, “Now farmers rely on chemical fertilizers to keep farming going. We also know that using too much chemical fertilizer and pesticide will cause soil fertility to decline. Soil compaction, but this is like smoking opium; you can't do without it.”
In addition, laws and regulations for cultivated land quality protection are incomplete, and restraint mechanisms are lacking. At present, there are no specialized laws or regulations for cultivated land quality protection, nor clear legal constraints on land contractors and operators. Although relevant provinces and regions have issued protection regulations, the enforcement standards are difficult to grasp, and their authority and mandatory force are insufficient.