| Torreya grandis ‘Merrillii’ is known as Chinese torreya, Taxus chinensis Torreyabelonging to the evergreen trees, a Chinese native tree species. It is our country’s uniquerare and high-end healthy dried fruit food. It is an excellent variation type of torreya treespecies, grown up by grafting. A3-year longterm field soil mornitoring and a3-yearlongterm micronutrient field experiment (2008-2010) were carried out to examine soilfertility and nut yield of Torreya grandis ‘Merrillii’ orchards in Shengzhou city, a key mainarea for this tree growth and its nut production in China. The main results were shown asfollows.(1) Soil analysis showed that levels of the available soil trace elements differedgreatly among the Torreya grandis forests, with less changes between years. The soil hotwater extracted boron (B) varied between0.01-1.29mg·kg-1, averaged at less than0.8mg·kg-1in the three years. While soil available zinc (Zn) and copper (Cu) ranged from1.2-27.5mg·kg-1, and0.13-17.1mg·kg-1, respectively, and their annual means were13.5-14.8mg·kg-1for Zn and2.7-8.6mg·kg-1for Cu. Concentrations of B and Cu in thefoliages also differed greatly both between forests and between years. By contrast, foliageZn concentration varied relatively small. During2008-2010, the annual meanconcentrations of foliage B, Cu and Zn were25.9-53.8,3.3-7.1and18.4-19.9mg·kg-1,respectively. In the kernel, crude fat content differed largely between forests (42.4-68.7%)but varied little with year, and this was similar to crude protein content ranged of13.86%to22.71%.(2) The objectives of the3-year longterm field experiment study were to elucidatethe effects of micronutrients application on plant growth and nut yield and quality ofTorreya grandis. Application of micronutrient fertilizers effectively improved theircorresponding soil available nutrient levels and concentrations in the plant foliage andkernel accordingly. Application of micronutrients in combination increased nut yieldremarkably and improved kernel quality as well. The effect of B, Zn, Cu and Mo appliedtogether had the greatest effect on increasing nut yield: the yield was increased by236.14%compared with control. While the farmer’s conventional fertilization and BZn combinedapplication improved crude fat content in the kernels significantly. Therefore, properapplication of micronutrient fertilizers could effectively improve the plant growth andnutrition of Torreya grandis, so that to improve productivity of Torreya grandis forests and nut quality.The3-year tracking survey in Shengzhou to the Torreya grandis forest soils showedthat much of the soils of forests are deficient in microelements due to natural soilconditions and especially due to the farmers’ blindly application of large amounts of NPKfertilizers and little of microelement fertilizers. These resulted in poor plant growth anddecline of nut yield. Therefore it is needed to call on application of micronutrient fertilizersand optimization of NPK fertilizer supply, so as to improve the Torreya grandis forest soilsand plant growth, nut production and its quality. |
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