Irrigation has more influence than fertilization on leaching water quality and the potential environmental risk in excessively fertilized vegetable soils

PLoS One. 2018 Sep 27;13(9):e0204570. doi: 10.1371/journal.pone.0204570. eCollection 2018.

Abstract

Excessive fertilization is a common agricultural practice that often negatively influence soil and environmental quality in intensive vegetable production systems in China. To reduce negative effects of excessive fertilization, current studies generally focused on fertilizer management but not irrigation. In this study, we investigated the effects of fertilization and irrigation on soil properties, leaching water characteristics, plant growth, cucumber yield, irrigation water use efficiency (IWUE) and partial factor productivity of nitrogen (PFPN) in a double cropping system. The treatments included (i) conventional irrigation with conventional N fertilization (IcNc), (ii) optimal irrigation with conventional N fertilization (IoNc), (iii) conventional irrigation with optimal N fertilization (IcNo), and (iv) optimal irrigation with optimal N fertilization (IoNo). In general, fertilization merely influenced concentrations of nitrate (NO3-), phosphorus (P) and potassium (K), but did not affect most leaching water characteristics. In contrast, irrigation influenced pH, EC and concentrations of P, K, Ca, Mg, Na and Cu. Cumulative leached amounts of NO3-, P, K, Ca, Mg, Na, Fe, Cu and Zn were significantly decreased by optimal irrigation as compared to conventional irrigation under same fertilization conditions, but not by optimal fertilization as compared to conventional fertilization under same irrigation conditions. The leachate volume was strongly positively correlated with cumulative leached amounts of all tested elements, and these relationships were obviously influenced by irrigation but not fertilization. The IoNo treatment significantly increased both IWUE and PFPN as compared to the IcNc treatment. However, the IcNo treatment only enhanced PFPN, while the IoNc treatment improved IWUE, when compared to the IcNc treatment. Our results suggested that irrigation has more influence than fertilization on leaching water quality and that the optimal irrigation combined with optimal fertilization was efficient in reducing the potential environmental risk caused by excessive fertilization in intensive vegetable production systems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agricultural Irrigation / methods*
  • China
  • Crop Production / methods*
  • Cucumis sativus / chemistry
  • Cucumis sativus / growth & development
  • Environment
  • Fertilizers* / analysis
  • Hydrogen-Ion Concentration
  • Nitrates / analysis
  • Nitrogen / analysis
  • Phosphorus / analysis
  • Potassium / analysis
  • Seasons
  • Soil / chemistry*
  • Vegetables / chemistry
  • Vegetables / growth & development*
  • Water Quality* / standards

Substances

  • Fertilizers
  • Nitrates
  • Soil
  • Phosphorus
  • Nitrogen
  • Potassium

Grants and funding

Funding was provided by the Special Fund for the National Key Research and Development Program of China (2016YED201003 to LG), the key projects of the Chinese Ministry of Science and Technology (2015BAD23B01-4) and the earmarked fund for China Agriculture Research System (CARS-25 to LG). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.