Ja. Diez et al., CONTROL OF NITRATE POLLUTION BY APPLICATION OF CONTROLLED-RELEASE FERTILIZER (CRF), COMPOST AND AN OPTIMIZED IRRIGATION SYSTEM, Fertilizer research, 43(1-3), 1996, pp. 191-195
A nitrogenous controlled release fertilizer (Floranid 32) and a treatm
ent of municipal organic waste compost were tested under two irrigatio
n managements (conventional and ET-adjusted irrigation rates) with the
aim of assessing risk of nitrate leaching to the aquifer. A check wit
hout N fertilizer was introduced. The experiment was carried out at La
Poveda Field Station (30 km SE Madrid, Spain) in alluvial soils with
water table depth at 4 m and under maize cropping. The experiment was
laid out in a randomized complete block design with three replications
, allocating 12 plots to each irrigation management. Although N fertil
izer rate (150 kg ha(-1)) was reduced at half as related to a previous
experiment, no difference in grain yields was observed. This result r
elates to a high content of soil-N. Floranid showed promising results
in controlling N-leaching in comparison with urea that exhibited an ac
celerated rate of N release which finally determines low use of N by t
he plant and marked NO3- leaching. Treatment of municipal waste compos
t showed NO3- concentrations in the soil water solution of similar val
ues as those of urea at 140 cm. ET-adjusted irrigation showed no drain
age during the corn growing season and lower NO3- concentrations in th
e soil water solution which could indicate a general lower rate of N s
olubilization.