Premium
On‐Farm Monitoring of Soil Nitrate‐Nitrogen in Irrigated Cornfields in the Ebro Valley (Northeast Spain)
Author(s) -
VillarMir Josep M.,
VillarMir Pere,
Stockle Claudio O.,
Ferrer Francesc,
Aran Miquel
Publication year - 2002
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2002.3730
Subject(s) - leaching (pedology) , agronomy , environmental science , fertilizer , crop , growing season , nitrate , nitrogen , soil horizon , soil water , biology , soil science , chemistry , ecology , organic chemistry
The irrigated area served by the Canal d'Urgell, a semiarid region in the Ebro Valley (northeast Spain), presents problems of ground water pollution by nitrates. Corn ( Zea mays L.) is widely grown in this area, and N fertilization in corn production is the major source of N input in the area, with application rates in excess of crop requirements. In this study, we monitored several commercial cornfields for soil NO 3 –N levels, crop N uptake, and crop productivity over a 2‐yr period to quantify the relationship among soil NO 3 –N, N fertilizer rates, crop N use, and N loss through leaching. Monitoring soil NO 3 –N profiles showed that in some fields, soil NO 3 –N was transported to deeper layers in the soil during the growing season. In many cases, important accumulation of NO 3 –N was observed at the bottom of the soil at physiological maturity, increasing the risk of winter leaching. Soil N availability, calculated as preplanting soil nitrate test + N fertilizer, was neither related to plant N uptake nor final biomass and grain yield. In some plots, the occurrence of drought during the growing season was more decisive than soil‐available N in explaining crop N uptake and grain yield differences. Available N levels found in the soil were above 370 kg ha −1 in all cases. Apparently, these levels were enough to satisfy the crop N requirements to achieve yields above 11 to 12 Mg ha −1 . Overall data showed that there is an excess of N in the system.