5Peacock W L, Christensen L P, Broadbent F E. Uptake, storage and utilization of soil-applied nitrogen by thompson seedless as affected by time of application[J]. Am. J. Enol. Viticult, 1989, 40:16-20.
6Sanchez E E, Righetti T L, Sugar D et al. Seasonal differences , soil texture and uptake of newly absorbed nitrogen in field-grown pear trees[J]. J. Hort. Sci, 1990, 65: 395-400.
7Mochizuki T, Kamakura J. Studies on the nitrogen nutrition of apple trees. Ⅱ . The relationships between the time of nitrogen and its distribution among the parts of fruit bearing trees[J]. Bull. Fac. Agr.Hirosaki Univ. 1971, 17:102-109
9Sanchez E E, Righetti T L, Sugar D et al. Effects of timing of nitrogen application on nitrogen partitioning between vegetative, reproductive, and structural components of mature comice pears [ J ]. Hort.Sci., 1992, 67:51-58