Nc. Stutterheim et al., THE EFFICIENCY OF FERTILIZER NITROGEN IN IRRIGATED, DIRECT-SEEDED RICE (ORYZA-SATIVA L) IN EUROPE, Fertilizer research, 37(3), 1994, pp. 235-244
Data from 35 experiments with direct seeded rice, performed between 19
81 and 1991 by national research institutes in five major rice growing
countries of Europe were analyzed to estimate the average efficiency
of fertilizer nitrogen (N). Pooled data from a four year regional surv
ey (1984-1988) on rice-based farming systems in the Camargue-region (4
3-degrees 20'-43-degrees 40' N) in the south of France, were used to p
erform a similar analysis. Experimentation during two years (1989-1990
) was carried out to assess the value of the N-utilization efficiency
within the range of N-limited growth and to obtain information on the
N-efficiency under controlled conditions. At reduced basal dressing of
N on soils with high soil organic matter content, the apparent N-reco
very was estimated at 0.21 to 0.32 kg N uptake per kg N applied. Avera
ge agronomic efficiency ranged from 12 to 17 kg grain dry mass per kg
N applied. High basal N-application on these soils resulted in yield l
oss. No consistent yield response to fertilizer-N input was found on s
oils with less than two percent organic matter, irrespective of fertil
izer timing. These results confirm the important role of soil organic
matter in rice cultivation. An average apparent N-recovery of 0.18 was
obtained with split application of N under controlled experimental co
nditions in the Camargue. Using a controlled release fertilizer, value
s of 0.58 and 32 kg.kg-1 were obtained for the apparent N-recovery and
agronomic efficiency, respectively. Hence, disregarding the economic
feasibility, considerable scope exists for improving N-efficiency in E
uropean rice cultivation.