Yield and nitrogen use efficiency of wheat increased with root length and biomass due to nitrogen, phosphorus, and potassium interactions. Issue 3 (13th March 2018)

• Record Type: Journal Article
• Authors: Duncan, Elliott G.; O'Sullivan, Cathryn A.; Roper, Margaret M.; Palta, Jairo; Whisson, Kelley; Peoples, Mark B.
• Is Part Of: Journal of plant nutrition and soil science. Volume 181:Issue 3(2018:Jun.)
• Page Start: 364
• Page End: 373
• Publication Date: 2018-03-13
• Subjects: crop nutrition -- grain yield -- nutrient availability -- rhizoboxes -- specific root length; Plants -- Nutrition -- Periodicals; Soil science -- Periodicals; 630
• DOI: 10.1002/jpln.201700376
• Languages: English
• ISSNs: 1436-8730

Abstract

Abstract: Balanced applications of nitrogen (N), phosphorus (P), and potassium (K) are known to increase grain yield of wheat but the impact of the interactions among N, P, and K on root growth and nitrogen use efficiency (NUE) have not been proven. The aim of this study was to investigate the effect of balanced applications of N, P, and K on the rooting patterns and NUE of wheat. Two glasshouse experiments were conducted. A rhizobox study was used to assess the impact of interactions among N, P, and K fertilisers on total root length, biomass, specific root length, root length density, N use efficiency (NUE), and N uptake efficiency of the shoots (NUpEshoot ) and N nutrition index. In a separate pot study, plants were grown to maturity to confirm the effect of the observed changes in root growth on NUE, NUpEgrain, and grain/biomass yield. In the rhizobox experiment when plants were supplied with N+P+K, total root biomass increased approximately six‐fold relative to plants grown with N alone or with no fertiliser. Plants exposed to N+P+K had NUpEshoot and NUE values that were five and ten times higher, respectively, than plants that received just fertiliser N. Plants supplied with N+P or N+P+K had N nutrition indices close to one (N‐adequate), while plants that only received N had an index of 0.62 (N‐deficient). The pot study confirmed that the changes in root length and biomass in plants exposed to N+P+K resulted in significant increases in NUE, NUpEgrain, shoot biomass, and grain yield at maturity. Interactions among fertiliser N, P, and K played a critical role in influencing root biomass and length, which was associated with increases in NUE, NUpEshoot and NUpEgrain .