Dynamic Changes In Nutrient Elements And Nutrient Diagnosis In Torreya Grandis ’Merrillii’

Torreya grandis ’Merrillii’, a landrace of T. grandism, is an important economic species in ZhejiangProvince. Developing the industry of T. grandis ‘Merrillii’,has not only increased seed yield byincreased use of fertilizer, but also increased economic return and the cost of production, which is notbased on the requirement of trees themselves in T. grandis ’Merrillii’. There is an insufficientunderstanding of dynamic changes in nutrition elements in T. grandis ’Merrillii’. In order to solve thisproblem, the seasonally dynamic change in mineral elements in leaves throughout a year was measuredand dynamic variation in nutrient elements in both leaves and seeds during seed growth anddevelopment and their relationship were analyzed with samples collected from a plantation of T. grandis’Merrillii’ Yvshu Village, Gulai Town, Shengzhou City, Zhejiang Province, which is one of mainproducing areas. In addition, reasons behind yellowing of shoots and leaves were investigated in termsof nutrient elements in both shoots and leaves. The main results showed as follows:1) The soil of T. grandis ‘Merrillii’ plantation was5.13in pH,61.37mg·kg-1in the content oforganic matter,210.82mg·kg-1in available N,196.27mg·kg-1in available P, and672.93mg·kg-1inavailable K. All in all, the plantation was high in soil fertility, but had been acidified.2) One-year-old leaves was highest in N content among all the elements measured, whichdecreased quickly by26.5%at the early stage of seed swelling, maintained at a stable level, andincreased in January of the following year. And P and K decreased in the whole sampling process by54.0%and42.9%, respectively. During the early stage of seed enlargement, N, P, K, Mg, and Zn in theleaves decreased to different extents, while Ca, Mn, and Cu in the leaf showed a rising trend in thewhole experiment process. Mg in the leaves had shown a declining trend; and P and K as well as Mgwere in significantly positive correlation, which indicated they promoted each other. The correlationbetween P and Ca as well as Mn was significantly negative, which revealed some antagonistic effect.And Ca and Zn were in significantly positive correlation.3) N, P, and K in the leaves decreased by26.5%,23.1%and36.2%respectively at the early stagewhen seeds enlarged, while N and P in the seeds decreased by15.4%and8.3%but K increased; Inleaves, Ca, Mn, and Cu showed a rising trend but Mg showed a declining trend, while contents of thesefour elements in the seeds decreased first, followed by an increase then; and Ca, Zn and Mn in seedswere in significantly positive correlation with P in leaves, while the correlation between P in seeds andCa in leaves was significantly negative. It is suggested that relatively more N, P and Ca were neededbefore the fast growth of seeds, K needed in mid-July, and Mg needed after harvest of seeds.4) The contents of N and Mn in the leaves of yellowing shoots were higher than those in normalones but the contents of Ca and Mg were lower. With the development of yellowing, the content of Mnin the leaves presented an increasing tendency while the content of Ca and Mg presented a decline. Thecontents of N, P and Mn in the yellowing shoots were higher than those in normal ones but the contentof Fe was lower. With the development of yellowing, the content of Mn presented an increasingtendency while the content of Fe presented a decline. It was inferred that shoot yellowing was correlated to a low level of Ca, Mg and Fe and a high level of N and Mn.In summary, the plantation of T. grandis ‘Merrillii’ was fertile in soil, but soil acidification was aproblem, which affected the balance between nutrients and effectiveness of nutrient utilization.Therefore, liming to adjust pH and supplement calcium, application of prescribed fertilizers based onsoil testing and fertilization of organic manure to balance pH are very important, which is needed forfurther study in the future.