Pecan Plantation Nutrient Diagnosis And Ecological Management Techniques

Sustainable forest management has attracted increasing attention with the aggravation offorest ecosystem degradation. It refers to the establishment and implementation of forestmanagement plans, aiming to regulate and permanently utilize forest products, as well asmaintain and improve the environmental functions of forests. Hickory (Carya cathayensis Sarg.)is a high-grade dry fruit and woody oil plant unique to China, mainly distributed in the borders ofZhejiang-Anhui provinces. In recent years, improper management and planning of hickoryplantation has produced many ecological and environmental problems, such as soil erosion,disease and insect pest, and deteriorated water quality, seriously restricting the sustainabledevelopment of hickory industry. Thus ecological management of hickory plantation becomesvery urgent.Technical measures for sustainable management of hickory plantation were proposed basedon the systematic analysis of soil properties in hickory producing areas and the distinctknowledge of the effects of natural conditions, soil type, and fertilization on plantationproductivity; major factors inducing soil erosion were revealed through the investigation ofcharacteristics of soil nutrient loss and the evaluation of soil erosion risk for hickory plantation;nutrient dynamics of hickory were explored based on nutrient reabsorption characteristics ofhickory during its growth and fruiting, as well as correlation analysis between nutrientcomposition in the seed kernel and soil nutrient; hickory special fertilizer and fertilizer expertsystem were developed, and hickory ecological management techniques were put forward.Finally, social and economical evaluation for the popularization and application of hickoryecological management techniques were carried out in order to explore the extension pattern ofthe ecological management.Focusing on the foundation of ecological management and application of hickory plantation,demonstration bases, experimental study and pilot test extension were implemented; forest sitequality, major factors affecting soil erosion, tree-body nutrient dynamics, tree nutrition diagnosis,and ecological management techniques were studied. The main results were as follows:(1) Dynamic monitoring (2007–2008) for the surface soil of hickory forestland in studyarea, as well as the comparison of soil physical and chemical properties of study area in1982and2008shows that soil acidification is serious in some areas of hickory forestland, especially fromJuly to September, with pH decreasing3.5units at most; the content of available N, P, K alldecreases with the development of fruit, of which available P has a lower level comparing withthe other two nutrient elements, less than5mg·kg-1in80%forest soil in July, which is thevigorous growth period of hickory.(2) Soil erosion runoff field was established in2005, Research results indicating the annualsoil erosion loss is25.6kg/hm2. Dynamic monitoring for the soil N, P, K of hickory plantation with vegetation and without for one year shows the total nutrient loss of non-vegetationforestland is3.372kg/hm2per year,68.7percent higher than forestland with vegetation (1.999kg/hm2), and K loss is most serious, accounting for76%of the total nutrient loss. Based on theintegration of RS and GIS, the spatial distribution of soil erosion risk was mapped. According toRUSLE model, major factors affecting soil erosion were examined; results indicate that soilfraction in January, vegetation fraction in September, and slope are the three most importantfactors affecting soil erosion risk.(3) According to hickory nutrient dynamics research, a highly significant correlation wasobserved between the content of N, P, and K in hickory leaves, and the content and concentrationof these three elements in leaves both decrease during the fruit growth period; there is also ahighly significant correlation between Ca and Mg in hickory leaves, and the two elementsaccumulate continuously during the growth cycle of leaves; the contents of N, P, K, Ca, and Mgincrease with the development of fruit, but the monthly accumulation rate of them vary; thecontent of N in hickory leaves and that in soil have a significant linear correlation.(4) It was found that the reflectivity of hickory leaves vary especially obviously at525-605nm bands with different nitrogen concentration treatment through solution culture experiment ofhickory seedlings in artificial climate chamber. Thus this range of bands can be used for thespectrum detection of hickory nitrogen level. The nitrogen concentration of1.5mmol·L~-1cansatisfy the growth need of hickory and protect the photosynthetic apparatus of it as well. The Pdemand of hickory seedlings is0.35mmol·L~-1and the optimal concentration of K is about1.0mmol·L~-1. Based on the correlation between soil nutrient, fertilizer amount and yield, specialfertilizer and fertilizer expert system for hickory are developed.(5) interplanting of hickory and green manure can increase biomass and the fresh biomass ofannual ryegrass is maximum, reaching55,000kg·hm~-2. It is found that broadcasting ryegrass,white clover, milk vetch, rape and natural growing grass can effectively improve the soiltemperature and ground humidity in plantation. The content of soil organic matter increased20%,7%,43%, and21%compared with control when broadcasting white clover, ryegrass, milk vetch,and rape, respectively. The soil catalase activity increases23.64%and13.92%whenbroadcasting white clover and ryegrass in July, respectively.