6th UF Water Institute Symposium Abstract

   
Submitter's Name Andre Luiz Biscaia Ribeiro Da Silva
Session Name Poster Session - Agricultural/Silvicultural Water
Poster Number 2
 
Author(s) Andre Luiz Biscaia Ribeiro da Silva,  Horticultural Sciences Department, University of Florida (Presenting Author)
  Lincoln Zotarelli,  Horticultural Sciences Department, University of Florida
  Michael Dukes, Agricultural and Biological Engineering Department, University of Florida
  Kati Migliaccio, Agricultural and Biological Engineering Department, University of Florida
  Edzard van Santen, Agronomy Department, University of Florida
   
  Spatial and temporal distribution of soil N under four irrigation systems as function of N fertilizer rate and timing of application in potatoes
   
  Agricultural areas with coarse-texture soils and shallow water table may require greater nitrogen (N) fertilizer supplementation than plant N requirements, which leads to N losses irrigation are not properly managed. The study objective was to evaluate the spatial and temporal distribution of soil N in coarse texture soils under seepage, tile drainage, subsurface drip (SDI) and sprinkler irrigation under a combination of different N fertilizer rates and timings of application. A factorial randomized complete block design with three N rates (0, 56, 112 kg.ha-1) applied at planting (Npl) and two N rates (56 and 112 kg.ha-1) at emergence (Neme) and at tuber initiation (Nti) was setup within each irrigation system for two seasons in Hastings, FL. Soil mineral N was determined in the 0-15, 15-30 and 30-60 cm soil depth layers at five-potato growth stages. Under seepage, tile drainage and SDI the water table was raised to irrigated the crop and the upward soil water flux held soil N longer in the root zone compared to sprinkler. A combined management of water table level and sprinkler irrigation can potentially reduce the downward movement of soil N. The application of 112 kg.ha-1 of N at planting resulted in higher soil residual N at the harvest compared to 56 kg.ha-1 in 2015 due to lower precipitation compared to 2016. Nti above 56 kg.ha-1 of N increased soil N at tuber maturation stage but there was no increase in tuber yield. In 2016 regardless of irrigation system and N rates, soil N concentration was lower than 5.8 mg.kg-1 at the potato harvest. The application of 56, 112 and 56 kg.ha-1 of N fertilizer at Npl, Neme and Nti, respectively, provided enough N to supply the potato crop with lowest soil N residual.