In the face of serious degradation and erosion in the Central Highlands, land restoration as well as erosion control measures are essential.
Newspaper Vietnamese culture interviewed Assoc.Prof.Dr. Trinh Cong Tu, Deputy Director of Central Highlands Soil, Fertilizer and Environment Research Center, under the Institute of Soil Agriculture, about solutions to restore and prevent soil erosion in the Central Highlands.
As a region with the most fertile soil conditions in our country, what are the differences in the land of the Central Highlands?
The concept of land is quite broad, here only discusses land, ie cultivated land or cultivated land.
As we know, the Central Highlands is famous for its red basalt strips, suitable for many types of crops from short-term crops such as maize, cassava, sugarcane, sweet potatoes … to long-term industrial crops such as coffee, pepper. , cashew, rubber, cocoa … or fruit trees such as durian, avocado, banana, citrus.
In other words, basalt is suitable for many crops due to its high fertility. The highlight is the thick arable layer, sometimes up to tens of meters. The physical features are quite ideal for the development of the root system such as small density, high porosity, good texture and quite durable in a flooded environment, good permeability and drainage. .
Although the land is fertile, but in recent years, people have over-cultivated to increase crop yields, what is the situation and what has the consequences been?
Talking about the Central Highlands, people often imagine that they are fertile basalt plateaus, but in fact, basalt accounts for less than one third of the area in about 5.5 million hectares of the whole region. The remainder includes gray soil and other soils with low fertility.
Even basalt soils, which are considered good for plants, exhibit many limitations such as low pH, strong nutrient fixation, poor alkaline cations, alkaline soil, low absorption capacity, With a rather high moisture content, with steep terrain, surface erosion often occurs due to rain …
Under these conditions, in order to achieve their high yield targets, farmers did not hesitate to invest a large amount of agricultural chemicals in their fields.
For example, to reach 3-4 tons of coffee or pepper products, people often apply 2-3 tons of NPK mineral fertilizers, 30-40 kg of micronutrients … In addition to preventing pests, diseases and weeds, Tens of kilograms of plant protection chemicals are sprayed per hectare every year.
As a result, the already acidic soil becomes even more acidic; organic matter content and mineral nutritional factors are decreased. The soil gradually loses its texture and becomes harder and hardened. Its ability to hold water and hold feces is poor. Heavy metals and residues of pesticides, diseases, and herbicides tend to accumulate. Environment is damaged, animals and beneficial microorganisms in the soil are seriously degraded …
The main soil types in the Central Highlands
These unpredictable impacts have adversely affected the growth and development of plants in general and crops in particular, causing the yield, quality of agricultural products and economic efficiency to decrease over time. In the case of only negative effects, the productivity of the land is so depleted that it cannot be replanted.
There is an opinion that land in the Central Highlands is currently degraded, leading to a decrease in productivity and quality of crops, especially industrial crops such as coffee and pepper, especially many diseases from the soil. How do you evaluate this situation?
Under the influence of unfavorable soil processes such as organic matter depletion, leaching, nutrient fixation, loss of alkalinity and acidification … as well as excessive human use of agricultural chemicals making the quality of agricultural land in the Central Highlands have fluctuated in a negative direction for the growth, development and creation of crop yields.
Compared to the beginning of the farming term, a number of fertility targets for coffee and pepper in the Central Highlands, after 10-20 years, have had many changes: the average pH decreased by 0.5-1.0 units. ; content of organic matter and essential nutrients decreased significantly; residues of plant protection drugs and heavy metal elements such as Cd, Pb, As, Zn, Cu …, although not exceeding the allowable threshold, tend to increase.
In which it is worth noting that in some places, Cu, Zn accumulated at an alarming rate. The density of beneficial microorganisms such as nitrogen fixation, phosphorus degradation, cellulose degradation, antagonism to fungi and pathogenic bacteria … is reduced, while harmful microorganisms tend to increase.
A series of coffee and pepper areas after liquidation have a nematode density of> 100 fish / 100g of land, which is not guaranteed for immediate replanting, but requires time and appropriate treatment measures, causing a significant impact. to the economic and social life of the people in the region, especially the community who directly produce coffee and pepper.
Besides, the majority of arable land in the Central Highlands region is on a steep slope, while the rainfall is quite large and distributed according to seasons. Surface erosion has been happening at an alarming rate.
According to the Central Highlands Soil, Fertilizer and Environment Research Center, on average, the amount of soil eroded in the uncultivated formula was 51.8 tons / ha / year, in the planting formula. annual is 33.6 tons / ha and perennial plants 7.7 tons / ha.
Soil in the Central Highlands has a steep slope, so every year in the rainy season, it is severely eroded
What action must we take in order to restore soil quality for the Central Highlands?
The land is considered to have potential but also contains many challenges for crop development like the Central Highlands. The view of use along with protection and improvement should be carried out throughout the farming process. To step up communication to change awareness, update knowledge and skills for sustainable farming, to protect and stabilize soil fertility for local people.
Accordingly, the yield goals set out should be realistic, within the soil’s stamina, ensuring sustainability. The investment in intensive farming should be calculated appropriately and balanced. Using varieties with good tolerance to pests, diseases, drought, and adverse weather.
Increase the use of organic fertilizers and biologically derived pesticides for agricultural chemicals. Minerals with heavy metal absorption properties such as bentonite, zeloite can be added to the soil, or some plants such as thyme, watercress, fern, marigold … can be used to treat land.
To limit erosion on sloping land, planting contour lines, terraced fields, creating a basin around the base of perennial plants, combining appropriate intercropping… should be recommended.
Experimental results of the Central Highlands Soil, Fertilizer and Environment Research Center show that: intercropping legumes on coffee gardens in the basic design phase reduces 10.9 tons of drifting soil / ha / year compared to pure planting; the measure of creating a basin around the base reduced 21.4 tons of floating soil / ha / year; creating sinks combined with intercropping legumes, reducing floating soil 25 tons / ha / year.
For rubber trees in the 2nd and 3rd years, the intercropping of food crops, beans or other types of green manure cover, the amount of eroded soil is reduced by 51.7-90.2% compared to pure rubber cultivation. not apply soil protection measures.
Thank you Sir!
NNVN Newspaper
