title: A lysimeter study of nitrate leaching, optimum fertilisation rate and growth responses of corn (Zea mays L.) following soil amendment with water-saving super-absorbent polymer.
abstract: BACKGROUND
  Nitrate leaching and the resulting groundwater contamination from intensive cereal production has become a major concern for long-term farmland efficiency and environmental sustainability in northern China. The aim of this study was to evaluate a water-saving super-absorbent polymer (SAP) for minimising NO(3)(-) leaching from soil and optimising corn growth and yield. Thirty-six undisturbed soil lysimeters were installed in a field lysimeter facility in drought-affected northern China to study the growth and yield characteristics of summer corn (Zea mays L.) as well as the amount of NO(3)-leaching losses under different fertiliser (standard, medium or 75% and low, or 50% of conventional fertilisation rate) and SAP (control, 0; level-1, 15 kg ha(-1) and level-2, 30 kg ha(-1)) treatments.
  
  
  RESULTS
  Corn yield fell by 19.7% under medium and 37.7% under low fertilisation; the application of SAP increased yield significantly by 44.4% on level-1 and 80.3% on level-2. Similarly, plant height, leaf area, number of grains as well as protein, soluble sugar and starch contents in the grain also increased with SAP treatment. Application of SAP at 30 kg ha(-1) plus half of conventional fertilisation can reduce maximum (64.1%) nitrate leaching losses from soil.
  
  
  CONCLUSIONS
  Application of SAP at 30 kg ha(-1) plus only half the amount of conventional fertiliser rate (150 kg urea, and 50 kg each of superphosphate and potassium sulfate) would be a more appropriate practice both for minimising nitrate leaching and sustainable corn production under the arid and semiarid conditions of northern China.
authors.affiliation: National Research Center for Intelligent Agricultural Equipments, Beijing, PR China.
authors.forename: M Robiul
authors.initials: MR
authors.lastname: Islam
authors.forename: Sishuai
authors.initials: S
authors.lastname: Mao
authors.forename: Xuzhang
authors.initials: X
authors.lastname: Xue
authors.forename: A Egrinya
authors.initials: AE
authors.lastname: Eneji
authors.forename: Xingbao
authors.initials: X
authors.lastname: Zhao
authors.forename: Yuegao
authors.initials: Y
authors.lastname: Hu
mesh_terms: D000042:Absorption; D000383:Agriculture / Q000379:methods; D016573:Agrochemicals / Q000737:chemistry*; D002681:China; D003247:Conservation of Natural Resources; D003889:Desert Climate / Q000009:adverse effects; D004040:Dietary Carbohydrates / Q000032:analysis; D005308:Fertilizers; D009566:Nitrates / Q000032:analysis*; D058458:Nitrogen Cycle; D014674:Plant Proteins, Dietary / Q000032:analysis; D018526:Plant Transpiration; D011108:Polymers / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry / Q000254:growth & development; D012987:Soil / Q000737:chemistry*; D014867:Water / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry* / Q000254:growth & development* / Q000378:metabolism
chemical_list: D016573:Agrochemicals; D004040:Dietary Carbohydrates; D005308:Fertilizers; D009566:Nitrates; D014674:Plant Proteins, Dietary; D011108:Polymers; D012987:Soil; D014867:Water