The long-term overloading, degradation and loss of black land in the three eastern provinces are becoming more and more serious.

In the past, "you can sprout with chopsticks" now, "Why don't you grow grain with fertilizer?"

In Zihe Village, Erjing Town, Bei'an City, Heilongjiang Province, Yan Zhongjie, secretary of the village branch, dug less than 30 centimeters with a shovel and exposed loess. "the black soil layer has fallen from an average of 60 to 70 centimeters in the 1950s to an average of 20 to 30 centimeters today, and continues to deteriorate every year." Yan Zhongjie said.

A reporter from the Economic Information Daily recently interviewed in the black soil region of Northeast China and found that due to long-term overload utilization, reuse and light maintenance, the deterioration and loss of black land resources showed an aggravating trend.

The black soil gets thinner and loses 1 centimeter a year.

Statistics from the Songliao Water Conservancy Commission of the Ministry of Water Resources show that the black soil layer of cultivated land in the Northeast Plain has dropped from 80 cm to 100 cm at the initial stage of reclamation to 20 cm to 30 cm, and the thickness of the black soil layer lost every year is about 1 cm. The black soil that forms this thickness takes about 300 to 400 years, and the loss rate is hundreds of times faster than the rate of soil formation.

Similar to the phenomenon of thinning of black soil layer and decline of soil fertility in Zihe Village, it is not an isolated case in Northeast China. On June 24, the Ministry of Agriculture held a meeting in Harbin to promote the implementation of the pilot project for the protection and utilization of black land in Northeast China. Heads of agricultural departments from four provinces (regions) in Northeast China attended the meeting. Yu Wenbo, an inspector of the Jilin Provincial Committee of Agriculture, said that the black soil area of Jilin Province can lose an average of 0.3 to 0.7 centimeters of topsoil every year, and the depth of the plough bottom of cultivated land has dropped from about 20 centimeters in the 1980s to 13 centimeters. At the same time, the quantity and quality of organic matter in the plough layer decreased, and the organic matter decreased at an average annual rate of 0.1%, resulting in the degradation of soil biological characteristics and an increase in the incidence of crop diseases and insect pests.

Arong Banner and Zhalaite Banner, which are located at the southern foot of Daxing'an Mountains, are typical black soil areas. with the rapid growth of population, the land reclamation rate and soil use intensity are increasing, and the cultivated land quality of black soil is "three low". According to Jia Yuefeng, deputy director of the Agriculture and Animal Husbandry Department of Inner Mongolia Autonomous region, first, the ability of ecological regulation and control is low. The mild erosion area of the cultivated land in these two banners accounts for 55.8% of the total cultivated land area, of which 19.7% of the cultivated land has more than moderate erosion, the topsoil in the region has become thinner, the surface gravel is covered with vertical and horizontal gullies, and some of the cultivated land is on the edge of abandoned cultivation. Second, the ability to resist natural disasters is low. The area of dry sloping land in Arong Banner and Zhalaite Banner accounts for 46.6%, which is a typical rain-fed agriculture with no irrigation conditions, dry land is prone to drought and depressions are prone to waterlogging. Third, the comprehensive production capacity is low, the thickness of the black soil layer of the two banners decreased from 60 to 100 cm to 20 to 30 cm, and the thickness of the plough layer decreased from 25 to 35 cm to 10 to 20 cm at the initial stage of reclamation.

Tan Zhijuan, a researcher at the Qiqihar Agricultural Technology Popularization Center, said that the valuable black land has appeared problems such as thinning of the soil layer, reduction of organic matter, and decline of fertility. "the black land in some major grain producing areas, from 'holding a handful of oil' and 'cutting chopsticks can sprout', has become today's' big sand bag, broken skin yellow, how fertilizer does not grow grain'.

The northeast black soil region is one of the three major black soil belts in the world, with a land area of 1.03 million square kilometers, of which cultivated land covers an area of 450 million mu, accounting for 22.2% of the total cultivated land in the country. In recent years, the northeast black soil region accounts for about 20% of the country's total grain output, and commodity grain accounts for more than 1% of the country's total grain output, which can meet the food supply of 50% of the country's urban population, and plays an unshakable role in ensuring national food security.

Chen Mengshan, secretary of the party group of the Chinese Academy of Agricultural Sciences, said that the degradation of black soil in Northeast China is prominently manifested in the following aspects: the decline of soil organic matter, the imbalance of nutrients, the thinning of the soil, the shallower tillage layer, the hardening of the soil, and the formation of erosion gullies in some areas. the soil is getting less. In recent years, the national implementation of high-standard farmland construction, soil testing formula fertilization, conservation tillage and other projects, the trend of degradation and loss of black soil resources has been delayed in some areas, but the overall deterioration of the situation has not been fundamentally reversed. Heavy and light farming is supported by chemical fertilizer.

Behind the "quantity and quality decline" of black land, in addition to the natural reasons such as too many hilly hills, loose surface layer of black soil, serious water erosion and wind erosion, it is also closely related to excessive reclamation and utilization, unreasonable farmland management and farming measures, and long-term neglect of soil and water conservation measures.

A reporter from the Economic Information Daily found that the sense of protection is not strong, and long-term predatory operation, reuse and light maintenance are the root causes of black land degradation. Zeng Yande, director of the planting Management Department of the Ministry of Agriculture, said that the purpose of the development of Beidahuang was to increase production capacity. In the process of development for many years, only attention was paid to development and no attention was paid to protection. It can be seen from the difficulty of returning straw to the field. Although returning straw to the field is an important measure to improve soil fertility, the enthusiasm of farmers is not high because of the difficulty of straw collection and the high cost of crushing.

Lu Changai, a researcher at the Institute of Agricultural Resources and Agricultural regionalization of the Chinese Academy of Agricultural Sciences, said: "about 60% to 95% of organic matter such as straw in the northeast black soil area is burned, and the amount of land returned is very small, resulting in the content of organic matter in the surface layer of the soil falling from the original 8% to less than 3%. The organic matter in the plough layer decreased at an average annual rate of 1 ‰."

Unreasonable planting system also leads to the loss of fertile black soil. The reporter learned that in recent years, due to the impact of planting benefits, the soybean planting area has decreased sharply, coupled with the influence of grain assessment indicators, the grain and bean rotation system is difficult to implement, resulting in the role of soybean nitrogen fixation field has not been brought into full play. At the same time, the development of planting and breeding industry is not coordinated, the development of herbivorous animal husbandry lags behind, the proportion of corn in-situ conversion feed is low, and the shortage of organic fertilizer resources is obvious. Heihe City, Heilongjiang Province, with high latitude, is the traditional main producing area of wheat and beans in China. The reporter learned from the Agricultural Bureau of Heihe City that the area of corn in Heihe City in 2011 was more than 1.2 million mu, while this year it reached 5.5444 million mu. Local agricultural cadres said that corn has been planted for many years, and the original rotation system has been destroyed, resulting in a single consumption of soil nutrients and the loss of black soil.

Experts say that the application of organic fertilizer and deep ploughing and loosening can effectively protect black soil, but these are labor-consuming and costly to produce. Although there are some subsidies, the benefits are narrow, the level of subsidies is low, incentives are insufficient, and promotion and application are limited. In order to promote stable grain production and increase production, farmers have to apply more chemical fertilizer. In recent years, the input of chemical fertilizer has increased year by year, and small-scale agricultural machinery has been widely used, resulting in the aggravation of soil hardening, thinning of plough layer, thickening, hardening and upward movement of plough bottom, deterioration of cultivated land quality and decrease of soil water storage capacity, which aggravates soil erosion.

Taking the use of chemical fertilizers as an example, farmers generally report that the increase in grain production mainly depends on the use of chemical fertilizers, knowing that it will cause soil consolidation, but they still use it. Liu Junli, a major rice grower in Fujin City, Heilongjiang Province, told the Economic Information Daily that more than 1200 mu of rice had been planted this year and 40 tons of chemical fertilizer had been bought for spring ploughing. "A few years ago, we planted our own contracted land and fertilized 20 to 30 jin per mu of land, but now the scale of farming has expanded. In order to increase yield, about 70 jin of fertilizer is used per mu of land." Liu Junli said, "now farmers are supported by chemical fertilizers, and we also know that excessive use of chemical fertilizers and pesticides will lead to a decline in soil fertility." The soil is hardened, but it's like smoking a big cigarette. "

In addition, the laws and regulations of cultivated land quality protection are not perfect, and the restraint mechanism is lack. At present, there are no special laws and regulations on the quality protection of cultivated land, and there are no clear legal restrictions on land contractors and operators. although the relevant provinces and regions have issued protection regulations, the standard of law enforcement is difficult to grasp, and the authority and compulsion are not enough.