Carya Cathayensis Sarg. Forest Soil Degradation And Its Improvement Through Fertilization

Carya cathayensis is our unique economic forest tree species, its nut nutritional value andmedicinal value and economic value are significant. Lin’an City of Zhejiang Province is the majorproduction area of C. cathayensis. Due to years of excessive and preferential application of chemicalfertilizers, C. cathayensis forest soil degradation is common now and this has resulted in poor growth ofC. cathayensis trees and nut yield severe loss in consequence. To this end, this paper carried out a soilsurvey in Lin’an, and field fertilizer experiment research as well. The following key results wereachieved:From the winter of2012to the spring of2013,200surface (0-20cm) soil samples were collectedfrom C. cathayensis forests and basic soil properties were analyzed. The results showed that soilacidification was common in the forests, in addition to nutrient supply imbalance, especially withnitrogen (N) accumulation significantly in most forest soils, in which over91%of the soil samples hadalkaline hydrolysis N>100mg/kg. Moreover, there were also some forest soils enriched withphosphorus (P). There was less than3%of the soil samples were with pH>7, and soil pH <6was morethan87%. The acute acid soils (pH <5) were45%. However, there were less than52%of the forest soilslow in available potassium (K)(80mg/kg or less).Soil Testing Formulated Fertilization trials results showed that C. cathayensis leaf N concentrationincreased with N fertilizer application. While application of organo-inorganic formulated fertilizers(OIF) and P fertilizer in combination resulted in more P accumulation in C. cathayensis leaves, whilecombined supply of OIF and K fertilizer had most benefit to increase nut yield. The improvement of nutproduction by proper application of combination of organic and inorganic fertilizers, through remedy ofsoil condition and plant growth, became evident in the2ndPPyear.