Effect of long-term irrigation patterns on phosphorus forms and distribution in the brown soil zone

PLoS One. 2017 Nov 20;12(11):e0188361. doi: 10.1371/journal.pone.0188361. eCollection 2017.

Abstract

Continuous application of P fertilizers under different irrigation patterns can change soil phosphorus (P) chemical behavior and increase soil P levels that are of environmental concern. To assess the effect of long-term different irrigation patterns on soil P fractions and availability, this study examined sequential changes in soil organic P and inorganic P from furrow irrigation (FI), surface drip irrigation (SUR), and subsurface drip irrigation (SDI) in the brown soil zone (0-60 cm) during 1998 to 2011. Analyses of soil P behavior showed that the levels of total P are frequently high on top soil layers. The total P (TP) contents of the entire soil profiles under three irrigation treatments were 830.2-3180.1 mg/kg. The contents of available P (AP) were 72.6-319.3 mg P/kg soil through soil profiles. The greatest TP and AP contents were obtained within the upper soil layers in FI. Results of Hedley's P fractionation indicate that HCl-P is a dominant form and the proportion to TP ranges from 29% to 43% in all three methods. The contents of various fractions of P were positively correlated with the levels of total carbon (TC), total inorganic carbon (TIC), and calcium (Ca), whereas the P fractions had negative correlation with pH in all soil samples. Regression models proved that NaHCO3-Po was an important factor in determining the amount of AP in FI. H2O-Po, NaHCO3-Po, and NaOH-Pi were related to available P values in SUR. NaHCO3-Po and NaOH-Po played important roles in SDI. The tomato yield under SUR was higher than SDI and FI. The difference of P availability was also controlled by the physicochemical soil properties under different irrigation schedule. SUR was a reasonable irrigation pattern to improve the utilization efficiency of water and fertilizer.

MeSH terms

  • Agricultural Irrigation / methods*
  • Agriculture / methods*
  • Calcium / chemistry
  • Carbon / chemistry
  • Fertilizers / analysis
  • Humans
  • Phosphorus / chemistry*
  • Soil / chemistry*
  • Solanum lycopersicum / growth & development
  • Water / chemistry

Substances

  • Fertilizers
  • Soil
  • Water
  • Phosphorus
  • Carbon
  • Calcium

Grants and funding

This work was supported by the National Basic Research Program (973) of China (No. 2011CB100502), http://program.most.gov.cn/; National Natural Science Foundation of China (41301530), http://www.nsfc.gov.cn/; the Scientific and Technological Projects of Shenyang City (Grant No. FF11-117-3-00) http://www.syscg.gov.cn; and the Fifth session of Geping Green Action-123 Project of Liaoning Environmental Research and Education (No. CEPF2012-123-1-7), http://www.cepfln.com/List.asp?ID=634. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.