The influence of granular and liquid top-dressed nitrogen on nitrogen use efficiency (NUE), grain yield and quality parameters of spring wheat (Triticum aestivum L.)
| dc.contributor.advisor | Pieterse, P. J. | en_ZA |
| dc.contributor.author | Mbangcolo, Mongezi Morrison | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of AgriSciences. Dept. of Agronomy. | en_ZA |
| dc.date.accessioned | 2018-08-18T13:09:06Z | |
| dc.date.accessioned | 2018-12-07T06:46:33Z | |
| dc.date.available | 2018-08-18T13:09:06Z | |
| dc.date.available | 2018-12-07T06:46:33Z | |
| dc.date.issued | 2018-12 | |
| dc.description | Thesis (PhD)--Stellenbosch University, 2018. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Nitrogen use efficiency (NUE) of major cereal grains including wheat (Triticum aestivum L.) is estimated to be approximately 50% due to losses from leaching, soil denitrification, gaseous plant emissions, volatilization and surface runoff. Use of liquid nitrogen fertiliser to improve grain yields and quality parameters and N use efficiencies has demonstrated positive results; however, responses are inconsistent. Low N use efficiencies indicate the need to improve crop N recoveries and possible lower environmental pollution and the already high production costs. Studies on application of granular and liquid N topdressings to wheat are limited in South Africa. Studies were conducted from 2013-2015 to evaluate the response of NUE, yield and quality parameters of spring wheat to granular (broadcast) and liquid (sprayed) N topdressings under field conditions at two locations (Roodebloem - 34o 13’31.55”S; 19o 26’13.76”E and Langgewens - 33° 16' 33.96" S; 18° 42' 14.4" E) of the Western Cape Province, and controlled glasshouse conditions (2013, 2014 and 2016, and 2014, 2015 and 2016) at the Department of Agronomy, University of Stellenbosch, South Africa. Following applications of N as limestone ammonium nitrate (LAN 28%) at 30 kg N ha-1 at sowing, granular [(LAN (28%), granular urea (46%)] and liquid [urea ammonium nitrate (UAN 32%), liquid urea (46%) solution] N topdressings (30 and 60 kg N ha-1) were applied by means of single (tillering), and split (tillering and flowering) application on spring wheat. The field study results showed that the interaction between locality and growing season significantly affected NUE and grain yields and Roodebloem showed significantly better responses in grain yield in two (2014 and 2015) of the three study years compared to Langgewens. The effect of N rate showed that higher mean grain yield was produced through the application of N at 60 kg ha-1 (3 920 kg ha-1) compared to 30 kg ha-1 (3 577 kg ha-1) at Langgewens in 2013. The N rate x method of N application interaction showed that grain yield was significantly improved by liquid N topdressing at 30 kg ha-1 compared to granular N at 30 kg N ha-1 and liquid N at 60 kg N ha-1. Roodebloem (3 090 kg.ha-1) produced significantly higher mean grain yield compared to Langgewens (2 084 kg ha-1). The protein content and falling number were not significantly affected by N treatment. In the first glasshouse experiment, UAN applied at 60 kg N ha-1 significantly improved grain yield compared to other treatments. The responses showed that 60 kg N ha-1 promoted significantly higher yields and yield parameters compared to 30 kg N ha-1 and that liquid N topdressings were superior compared to granular applied N throughout the study. Similarly, in the second glasshouse experiment, plant responses increased with increasing N rates. The method x timing interaction showed significant differences due to timing of N application for liquid N topdressings. Plants treated with liquid N once at tillering showed superior responses compared to split applications of liquid N. NUE studies showed that different N use efficiency parameters were significantly improved by liquid N topdressings where the effects were significant both under field and glasshouse conditions. Seasonal rainfall was overall the main contributing source of variation in the studies conducted under field conditions . | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Stikstofverbruikdoeltreffendheid (SVD) van die belangrikste graangewasse insluitend koring (Triticum aestivum L.) word geskat op ongeveer 50% as gevolg van verliese deur loging, grond denitrifikasie, afskeidings as gasse deur plante, vervlugtiging en oppervlakafloop. Die gebruik van stikstofbemesting in vloeibare vorm om graanopbrengste, kwaliteitsvlakke en stikstofverbruikdoeltreffendheid te verbeter, het positiewe resultate opgelewer maar die reaksies was wisselvallig. Lae stikstofverbruikdoeltreffendheid dui op die behoefte om stikstof (N) verhaling, omgewingsbesoedeling en hoë produksiekoste te verbeter. Baie min ondersoeke na toediening van N in korrelvorm en vloeistofvorm as kopbemesting is nog in Suid-Afrika uitgevoer. Ondersoeke na die SVD, opbrengs en kwaliteitsveranderlikes van lentekoring in reaksie op toediening van N kopbemesting in korrelvorm (uitgestrooi) en vloeistofvorm (oorhoofs gespuit) is van 2013 tot 2015 uitgevoer onder droëlandtoestande op twee lokaliteite (Roodebloem - 34o 13’31.55”S; 19o 26’13.76”E en Langgewens - 33° 16' 33.96" S; 18° 42' 14.4" E) in die Wes Kaap Provinsie. Twee soortgelyke ondersoeke is onder beheerde glashuistoestande (2013, 2014 en 2016, en 2014, 2015 en 2016) by die Departement Agronomie, Universiteit van Stellenbosch, Suid-Afrika uitgevoer. Nadat kalksteen ammonium nitraat (KAN 28%) teen 30 kg N ha-1 met saai toegedien is, is N kopbemesting (30 en 60 kg N ha-1) in korrelvorm [(KAN (28%), ureumkorrels (46%)] en vloeistofvorm [ureum ammonium nitraat (UAN 32%), opgeloste ureum (46%)] toegedien as enkeltoediening (stoelvorming) en gesplete toediening (stoelvorming en blomvorming) op lentekoring. Die resultate van die veldproef het aangedui dat die interaksie tussen lokaliteit en groeiseisoen SVD en graanopbrengste betekenisvol beïnvloed het en Roodebloem het betekenisvol beter graanopbrengste as Langgewens gelewer in twee ( (2014 en 2015) van die drie seisoene. Die invloed van N vlak het getoon dat hoër gemiddelde graanopbrengste verkry is deur toediening van 60 kg N ha-1 (3 920 kg ha-1) vergeleke met 30 kg N ha-1 (3 577 kg ha-1) op Langgewens in 2013. Die N vlak x N toedieningsmetode interaksie het aangedui dat graanopbrengs betekenisvol verbeter is deur toediening van vloeibare N kopbemesting teen 30 kg ha-1 vergeleke met korrel N toediening teen 30 kg N ha-1 en vloeibare N toediening teen 60 kg N ha-1. Roodebloem (3 090 kg ha-1) het ‘n betekenisvol hoër gemiddelde graanopbrengs getoon as Langgewens (2 084 kg ha-1). Die proteieninhoud en valgetal is nie betekenisvol verhoog deur N behandelings nie. In die eerste glashuisproef het UAN wat teen 60 kg N ha-1 toegedien is graanopbrengs betekenisvol verhoog vergeleke met ander behandelings. Die resultate het aangetoon dat 60 kg N ha-1 betekenisvolle beter graanopbrengste en oeskomponente tot gevolg gehad het vergeleke met 30 kg N ha-1 en dat vloeibare N kopbemesting beter presteer het as korrelvorms van N gedurende die verloop van die studie. Soortgelyke resultate is in die tweede glashuisproef waargeneem waar plante se reaksie verbeter het met hoër N toedieningsvlakke. Die toedieningsmetode x toedieningstyd interaksie het betekenisvolle verskille aangetoon ten opsigte van tyd van N toediening vir vloeibare N kopbemestings. Plante wat een keer met vloeibare N bemesting behandel is het beter reaksies getoon as plante wat gesplete toedienings van dieselfde hoeveelheid N gekry het. SVD ondersoeke het getoon dat verskillende SVD veranderlikes betekenisvol verbeter het met toediening van vloeibare N kopbemesting beide onder veldtoestande en in die glashuisproewe. Variasie in seisoenale reënval was die hoof bydraende faktor wat bygedra het tot die variasie wat in die veldproewe waargeneem is. | af_ZA |
| dc.format.extent | xix, 233 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/104820 | en_ZA |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Wheat –- Quality | en_ZA |
| dc.subject | Wheat -- Yields | en_ZA |
| dc.subject | Triticum aesitivum –- Yields | en_ZA |
| dc.subject | Crops and nitrogen | en_ZA |
| dc.subject | Nitrogen fertilizers -- Effectiveness | |
| dc.subject | Liquid fertilizers | |
| dc.subject | UCTD | |
| dc.title | The influence of granular and liquid top-dressed nitrogen on nitrogen use efficiency (NUE), grain yield and quality parameters of spring wheat (Triticum aestivum L.) | en_ZA |
| dc.type | Thesis | en_ZA |