In recent years, trimming and pruning of the canopy of tea plants have been performed every year after the second crop, resulting in the accumulation of large quantities of pruned shoots (litter) in the space between hedges. The nitrogen fertilizer applied in the space between the hedges could not reach the soil easily because of accumulation of this litter, and we believe that it became a factor in the decline in the efficiency of fertilizer application. Therefore, in a tea field in which fertilizer was applied over the accumulated litter in the space between hedges, we analyzed the amount of inorganic nitrogen in the soil and the contribution rate of the nitrogen fertilizer in flush seasons by using the 15N-tracer method, and we investigated the influence of this litter on the fertilizer application efficiency.
The amount of inorganic nitrogen in the soil remained low in the tea field, even when ammonium sulfate and rapeseed oil cake were used. The 15N contribution rate of the second flush was 4.8% and the utilization rate of the nitrogen fertilizer in the first and second flush was 3.8%; these values were lower than those in a tea field without litter. Consequently, it was thought that the litter accumulated after trimming and pruning in the space between hedges might have been a factor responsible for the decline in fertilizer application efficiency.
