Nguyen Ngoc Tan
Nguyen Luong Ngoc
Nguyen Sy Huong
INTRODUCTION
It was realised that there are some abnormal phenomena in sowing P.merkusii in practice: white leaves, yellow leaves, weak growth, quite high mortality, and carcospora needle blight are commonly found.
Micro-elements proved to be important for crops. Therefore, trying to use micro-elements to increase the tolerance of P.merkusii to adverse conditions (fungus diseases, drought) and assimilation ability of trees is necessary.
METHODS AND RESEARCH CONTENT
Experiments were carried out from December 1973 to July 1976. Microelements: B (H3BO3), Mn (KMnO4), Zn (ZnSO4) were used separately or in combination for treating seeds and for irrigating (normal irrigation and irrigation from the base). Aspects to be investigated are:
. Influence of seed treatment on germination
. Influence of seed treatment and irrigation on growth process and tolerance ability of pines
. Influence of combination of micro-elements and macro-elements (in different ratios) on physiological characteristics of P.merkusii seedlings grown in nursery bed having irrigation from the base.
Figures such as evaporation intensity, level in lack of water, water-types in leaf, CO2 absorption and O2-evolving ability, chlorophyll content, NPK content in leaf and figures in biomass and growth were used for comparative evaluation.
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Oldest news
- study on prevention and control of cercospora needle blight for pines in nursery (1965-1970, 1973, 1977)
- growth situation of some pine species at dailai from 1975 to 1977
- preliminary study on increment rules to serve as temporary basis for p.kesiya management at lamdong province (1977)
- study on biological characteristics of cyrtotrachelus longimarus worms and control measures
- preliminary results of investigation on erosion status and measures for erosion prevention in soilsused for planting styrax tonkinensis at tuquan,hatuyen province (1974 - 1976)
