Is the altered taste of vegetables and melons caused by chemical fertilizers?

1. Is the bland taste of vegetables and melons related to chemical fertilizers?

Scientific fertilization does not affect the taste of fruits and vegetables; the key is not to overuse them or rely excessively on chemical fertilizers

Some people say that fruit is no longer sweet and vegetables no longer have flavor, and that this is all because of the use of chemical fertilizers. Is that true?

Zhang Fusuo: Whether vegetables or melons and fruits taste good is related to many factors, including their own variety, cultivation method, soil and climate, among others. Fertilizer is only one aspect. It is widely recognized that scientific fertilization not only does not have a negative impact on the taste of fruits and vegetables, but can also improve crop quality. For example, nitrogen fertilizer can increase protein content; potassium fertilizer can increase sugar content and VC content; phosphate fertilizer promotes early ripening and increases oil content, etc. But if chemical fertilizer is used in excess, just as when a person eats too much, the metabolic balance will be disrupted, and the quality and taste of fruits and vegetables will decline.

How do farmers currently fertilize?

Gong Jinxing: My family grows 11 mu of watermelons, and we apply fertilizer three times per season: the first is the base fertilizer around Qingming, with 4 cubic meters of manure and 50 jin of chemical fertilizer per mu; after 40 days, we apply seedling fertilizer, with 50 jin of compound fertilizer per mu; 20 days before harvest, we apply another round of fertilizer, 30 jin. Roughly calculated, one mu of watermelons requires 1.5 bags of chemical fertilizer.

Fan Yongqiang: Overall, the amount of chemical fertilizer used in Gong Jinxing's melon field is not high, but structurally nitrogen can still be further reduced and the proportion of organic fertilizer and potassium fertilizer increased. In our grassroots promotion work, we have found that economic crops such as fruits and vegetables generally have the phenomenon of large nitrogen fertilizer use and insufficient organic fertilizer, while organic fertilizer is a key factor in improving the taste of fruits and vegetables.

Can we do without chemical fertilizers?

Gong Jinxing: “For crops to flourish, fertilizer is the key.” The land is now getting more and more demanding. I know that using too much chemical fertilizer is not good, but I cannot stop. The average yield of the watermelons I grow is only just over 6,000 jin per mu. Once chemical fertilizer is reduced, the yield will definitely decline as well.

He Caiwen: Agricultural production cannot do without chemical fertilizers, but it also cannot rely entirely on them. Chemical fertilizers are the “food” of crops. Research shows that their contribution rate to grain yield increase reaches 30%-50%. For example, vegetable crops generally have a short growth period, and the yield per mu can be as high as more than 10,000 jin. Without sufficient fertilizer support, a single season of crops would consume nutrient reserves that the soil accumulated over many years, and a bumper harvest would be unimaginable. Therefore, we must have a correct understanding of chemical fertilizers, and scientific and rational use is the key.

⟦NL> Do green products not use chemical fertilizers?

Zhang Fusuo: The nitrogen, phosphorus and potassium elements in chemical fertilizers are all natural substances in nature, not toxic substances. China's A-level green food standards stipulate that chemical fertilizers may be used to a limited extent. European organic agriculture regulations allow the use of phosphate rock powder and potassium ore.

What is the overall situation of chemical fertilizer use in China?

He Caiwen: China's chemical fertilizer use is still relatively high overall. Statistics show that the national annual chemical fertilizer use is more than 58 million tons, the highest in the world, but the utilization rate in the current season is only 33%, about 20 percentage points lower than that of developed countries.

The main problems currently existing: First, excessive application of chemical fertilizers, especially for fruit and vegetable crops, which have developed rapidly in recent years, making this problem more prominent. Second, the application structure is unreasonable, and the ratio of nitrogen, phosphorus and potassium does not match the needs of crops and soil. Third, the utilization rate of organic fertilizer resources is low, with actual utilization less than 40%. Fourth, fertilization methods are backward, with traditional manual fertilization still dominant, and mechanical fertilization accounting for only about 30% of the area of major crops.

2. How great is the impact of excessive fertilization?

It brings problems of soil degradation such as non-point source pollution and soil acidification. Reasonable “weight loss” will not affect the supply of agricultural products

What impacts will excessive application of chemical fertilizers bring?

Zhang Fusuo: Excessive fertilization not only affects the quality of agricultural products, but also leads to soil degradation problems such as soil acidification and secondary salinization. For example, in soil acidification, it takes tens of thousands of years for the pH value of natural soil to drop by one unit, while China's cultivated land dropped by 0.5 units in 30 years. Research shows that for every one-unit drop in soil pH, the activity of the heavy metal cadmium increases 100 times, increasing the risk of heavy metal pollution.

Fan Yongqiang: We conducted tests in some orchards in the Jiaodong region, and the pH value dropped to 4.5. Under such conditions, the soil nutrient ratio is imbalanced, pests and diseases increase, causing crop yield reductions of more than 30%. In addition, excessive fertilization can also cause soil compaction, decline in soil fertility, non-point source pollution, and affect the quality and safety of agricultural products. For example, applying a large amount of nitrogen fertilizer alone will cause nitrate to accumulate in large amounts in plant tissues, resulting in increased nitrate content.

He Caiwen: Rational fertilization will not cause soil safety problems. The results of 170 consecutive years of experiments at the Rothamsted Experimental Station in the United Kingdom show that scientific application of chemical fertilizers will not cause soil quality decline, and can promote organic matter through inorganic means and improve cultivated land quality.