Excessive application of nitrogen and phosphorus fertilizers induces soil acidification and phosphorus enrichment during vegetable production in Yangtze River Delta, China

Abstract

Intensive vegetable cultivation has developed very rapidly in China, and investigation of current soil nutrient problems in vegetable fields and their potential environmental risk is important for local soil nutrient management strategies. Three hundred and sixty-six soil samples were collected from greenhouse vegetable fields, open vegetable fields and rice/wheat rotation fields in southern Jiangsu Province, the most intensive vegetable-producing areas in Yangtze River Delta, China, for the analysis of their soil fertility status. Soil acidification and P enrichment were the main problems identified in this area of vegetable production, with about 20 and 17% of the open and greenhouse vegetable field soils, respectively, being extremely acid with soil pH values below 5.0. In contrast, no soils under rice/wheat rotation fields were as acidic. Percentages of sites with Olsen-P concentrations < 90 mg/kg were 61, 85 and 0% for soils growing greenhouse vegetable, field vegetable and rice/ wheat, respectively. The nitrogen (N) surplus for vegetable fields exceeded 170 kg/ha/crop, and the phosphorus (P) surplus exceeded 40 kg/ha/crop. Thus, current vegetable production leads to potential environmental risks of N and P pollution of nearby aquatic bodies. Insufficient supplementation with potassium fertilizers was found in some vegetable fields. Several ameliorative measures are proposed.

High phosphorus at seedling stage decreases the post-transplanting fertiliser requirement of cucumber (Cucumis sativus L.)

“…This idea deserves further field testing in future research. Liang et al (2013) reported the amounts of P input for open vegetables and greenhouse vegetables in Yangtze River Delta of China were 72.9 kg/ha/crop and 87.8 kg/ha/crop respectively, which was much greater than their removals (32.2 kg/ha/crop). If our approach proves feasible under field conditions, vegetable production could be sustained with considerably smaller P inputs than currently used, providing tangible economic and environmental benefits.…”

“…In China, P concentrations in soils under agricultural and horticultural use are increasing because of the excessive application of inorganic P fertilizer and animal manure (Ju et al, 2007;Liang et al, 2013). This over-application of P to soils has been linked to surface water eutrophication (McDowell and Sharpley, 2004;Schoumans et al, 2014), such as Lake Chao in China (Zhang et al, 1999), because P is normally the limiting nutrient for aquatic biomass (Allen et al, 2006).…”

Environmental costs of China’s food security

“…It is particularly severe for vegetable crops (Ju et al, 2007) and it appears to have been getting worse in recent years (Guo et al, 2010;Liang et al, 2013). Guo et al suggest that it has been primarily caused directly by high inputs of synthetic N fertilizer and not indirectly by acid deposition (Guo et al, 2010), but other scientists believe that acid rain and ammonia deposition are also significant causes.…”

“…Thus, the total cereal loss could be 80-90 million t per yr À1 . Losses from vegetables could be more extreme given the high levels of synthetic N and manure overuse they receive (Liang et al, 2013) and their greater vulnerability to diseases (Hoffland et al, 2000) and high market value. Losses from open field vegetables are assumed to be 5% and covered vegetables 10% on the grounds that the latter suffer more from disease losses (Jarvis, 1992;Dordas, 2008) and from soil acidification and salinization .…”

Coadaptation of Plants to Multiple Stresses in Acidic Soils

“…In China, acidic soils account for approximately 22.7% of the total land area (Shen, 2008). In recent decades, soil acidification has been accelerated to some extent by various anthropogenic activities, especially the overuse of nitrogen (N) fertilizer (Guo et al, 2010;Liang et al, 2013a). Approximately 60% of acidic soils are distributed in humid tropical areas (von Uexküll and Mutert, 1995).…”