"In the past 20 years, the amount of fertilizer used in agriculture in our country has increased four to five times. Unbalanced fertilization not only causes waste of money and labor, but also causes serious degradation of land, "said Dr. Nguyen Quang Hai, Deputy Director of the Institute of Soils and Fertilizers (Institute of Agricultural Sciences Vietnam).
Dr. Nguyen Quang Hai - Vice Director of the Institute of Soils and Fertilizers (Vietnam Academy of Agriculture).
At the end of 2015, the Soils and Fertility Institute of Vietnam organized a workshop entitled "Vietnam Land - Current Status and Challenges".
At this event, most scientists acknowledge that Vietnam's agricultural land is being degraded and polluted. The perpetrators "poison" the land in addition to the amount of heavy metal residues, abuse of pesticides, the imbalance of fertilizers causing soil degradation both physically, chemically and biologically.
Is there any concrete evidence? Unfortunately, at this time, the scientific community has yet to point out the evidence. According to TS Hai: "We have long lacked the fundamental and systematic research topics on soil pollution.
However, it can be explained from other observations. The abuse of chemical fertilizer is increasing. On average, each person has about 1.2 hectares of agricultural land, while in our country, only about 0.1 hectare per person.
Due to population pressure of our country is too large, increasing food demand forcing agricultural production to find ways to improve production. The introduction of new short-term varieties, high yield potential, intensive farming increases the demand for nutrient supplements in very large soil.
"Approximately 20 years ago, on average 1 hectare of agricultural land, people applied about 104 kg of fertilizer. In recent years, it has increased to about 680 kg of fertilizer, "Hai said.
According to Chinese calculations, fertilizer determines crop yields of about 40%; Like 30%, pesticides 20% and mechanized 10%. Due to the contribution of fertilizer to the increase of productivity is very clear so farmers tend to fertilize more and more. But if you fertilize the innocent, not suitable for the nutrient uptake of plants, it will cause unpredictable consequences.
TS Hai said: The use of fertilizers in Vietnam is very low. On average, plants only absorb about 50% of protein, 30% phosphorus, and 60% of potassium compared to the amount of manure applied. The rest is lost to the environment in many different ways, causing pollution.
In addition, the amount of organic fertilizer used less and less. Chemical fertilizer occupies the upper hand. If too much chemical fertilizers will make the soil become hardened, reduced airflow, poor water retention ... The soil gradually degrades physically.
The implications are that aerobic microorganisms, mostly useful microorganisms, begin to decline. Meanwhile, harmful microorganisms (which prefer to live in anaerobic environments) are growing and damaging to crops. The risk of infected plants will increase. The risk of soil degradation biologically is inevitable.
Applying a lot of chemical fertilizers also causes the soil's absorption system to be destroyed, chemically inert soil, and the ability to keep fertilizer in the soil for gradual supply according to the demand of the crop.
If the survey in coffee growing areas, pepper concentrate in the Central Highlands will see, many farmers apply thousands of kg fertilizer / ha, mainly inorganic fertilizers. These are high value crops and people do not have money to pour fertilizer into. Even, the pesticides too, every disease is sprayed, no disease also spray prevention.
When the soil is hardened, the roots underdeveloped, low nutrient uptake and harmful bacteria increase, pestilence will arise (typically slow death in pepper plants). By land and trees have a causal relationship.
