title: The effect of nutrients shortage on plant's efficiency to capture solar radiations under semi-arid environments.
abstract: Radiation use efficiency (RUE) is considered critical for calculation of crop yield. The crop productivity can be improved by increasing the interception of solar radiation and maintaining higher RUE for plants. Irrigation water and nitrogen (N) supply are the main limiting factors for RUE in maize (Zea mays L.) across the semi-arid environments. Field experiments were conducted during two consecutive growing seasons (2009-2010) to optimize RUE in relation to N application timings and rates with varying irrigation water management practices. In experiment 1, three N application timings were made, while in experiment 2, three possible water management practices were used. In both experiments, five N rates (100, 150, 200, 250, and 300 kg N ha-1) were applied to evaluate the effects of irrigation water and N on cumulative photosynthetic active radiation (PARi), dry matter RUE (RUEDM), and grain yield RUE (RUEGY). The results demonstrated that cumulative PARi and RUEs were not constant during the plant growth under varying the nutrients. The water and N significantly influenced cumulative PARi and RUEs during the both growing seasons. In experiment 1, the maximum cumulative PARi was observed by application of 250 kg N ha-1in three splits (1/3 N at V2, 1/3 N at V16, and 1/3 N at R1 stage), and the highest RUEDMwas achieved by the application of 300 kg N ha-1. However, the highest RUEGYwas observed by application of 250 kg N ha-1. In experiment 2, the maximum cumulative PARi was attained at normal irrigation regime with 250 kg N ha-1, while the highest RUEDMand RUEGYwere recorded at normal irrigation regime with the application of 300 kg N ha-1. The regression analysis showed significant and positive correlation of RUEGYwith grain yield. Therefore, optimum water and N doses are important for attaining higher RUE, which may enhance maize grain yield semi-arid environment; this may be considered in formulating good agricultural practices for the environmental conditions resembling to those of this study.
authors.affiliation: Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari, 61100, Pakistan. mohkum@ciitvehari.edu.pk.|AgWeatherNet, Washington State University, Prosser, Washington, 99350, USA. mohkum@ciitvehari.edu.pk.
authors.forename: Hafiz Mohkum
authors.initials: HM
authors.lastname: Hammad
authors.affiliation: Department of Environmental Sciences and Engineering, Government College University, Faisalabad, 38000, Pakistan.
authors.forename: Farhat
authors.initials: F
authors.lastname: Abbas
authors.affiliation: Agro-Climatology Laboratory, Department of Agronomy, University of Agriculture, Faisalabad, 38040, Pakistan.
authors.forename: Ashfaq
authors.initials: A
authors.lastname: Ahmad
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China. shah.fahad@mail.hzau.edu.cn.
authors.forename: Shah
authors.initials: S
authors.lastname: Fahad
authors.affiliation: Department of Civil Engineering, Mehran University of Engineering and Technology, Jamshoro, Sindh, Pakistan.
authors.forename: Khalifa Qasim
authors.initials: KQ
authors.lastname: Laghari
authors.affiliation: Department of Biological Sciences, Faculty of Science, King Abdulaziz University, 21589, Jeddah, Saudi Arabia.
authors.forename: Hesham
authors.initials: H
authors.lastname: Alharby
authors.affiliation: Lasbela University of Agriculture, Water and Marine Sciences, 90150, Blochistan, Pakistan.
authors.forename: Wajid
authors.initials: W
authors.lastname: Farhad
mesh_terms: D000383:Agriculture / Q000379:methods*; D055864:Droughts; D005308:Fertilizers; D009584:Nitrogen / Q000378:metabolism / Q000494:pharmacology; D012621:Seasons; D012993:Solar Energy; D014867:Water / Q000737:chemistry; D003313:Zea mays / Q000187:drug effects / Q000378:metabolism / Q000502:physiology / Q000528:radiation effects
chemical_list: D005308:Fertilizers; D014867:Water; D009584:Nitrogen
keywords: Cumulative photosynthetic active radiation; Maize; Nitrogen; Radiation use efficiency; Water