Soil quality evolution after land use change from paddy soil to vegetable land

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Land use change from traditional paddy rice-wheat rotation to continuous vegetable cultivation is prevalent in the Taihu Lake region.
• This shift has occurred over the past 15-20 years in Jiaxin prefecture, northern Zhejiang province.
• Concerns exist regarding the environmental impact of intensive vegetable farming.

Purpose of the Study:

• To assess the impact of land use change on soil quality in the Taihu Lake region.
• To quantify changes in soil pH, salt content, and nutrient levels.
• To evaluate potential risks of water pollution associated with current farming practices.

Main Methods:

• Conducted a survey across 15 villages in Jiaxin prefecture.
• Collected and analyzed 150 soil samples and 86 vegetable plant samples.
• Compared current soil conditions with historical data and traditional cropping systems.

Main Results:

• Significant soil acidification observed, with average pH 5.4 and 61% of samples below pH 5.5.
• Increased fertilizer salt accumulation, with 36.2% of samples exceeding 0.3% salt content.
• Over-accumulation of nitrate nitrogen (279 mg/kg) and available phosphorus (45-115 mg/kg) detected, significantly higher than in rotation soils.

Conclusions:

• Continuous vegetable cultivation drastically alters soil quality, leading to acidification and nutrient imbalances.
• High nitrate and phosphorus levels pose risks of groundwater and surface water pollution.
• Sustainable land management practices are needed to mitigate negative environmental impacts in vegetable-growing regions.