Zhang X.-X.,CAS Institute of Soil and Water Conservation |
Liu Z.-W.,Northwest University, China |
Liu Z.-W.,Ministry of Agriculture Key Laboratory of Plant Nutrition and the Agri environment in Northwest China |
Bing Y.-H.,Northwest University, China |
And 2 more authors.
Chinese Journal of Applied Ecology | Year: 2014
Whether the content and composition of soil humus in pure forest change due to its simple component of litter and specificity of single-species dominant community is a key problem for forest sustainable management. In this study, soils from 6 kind of pure forests in semi-arid low-hilly area of Inner Mongolia were collected and their humus and other biochemical properties were measured to investigate the differentiation of soil humus and the impact factors. The results showed that the soil of Picea asperata and Betula platyphylla pure forests had the highest contents of humus and better condensation degrees and stabilities, followed by that of Populus simonii, Larix principis-rupprechtii and Ulmus pumila pure forests, while the soil of Pinus tabuliformis pure forest had the lowest content of humus, condensation degree and stability. There were significant positive correlations between soil microorganism biomass, activity of phosphatase and the content and stability of soil humus. In contrast, the soil peroxidate, dehydrogenase activity and soil humus content showed significant negative correlations with each other. Furthermore, the enhancement of dehydrogenase activity might decrease the stability of humus. There were significant positive correlations between available N and the content and stability of soil humus, but total Cu, Zn and Fe had negative correlations with them, and total Cu and Fe might reduce the stability of humus as well. The particularity of pure forest environment and litter properties might be the key inducement to soil humus differentiation, thus reforming the pure forest through mixing with other tree species or planting understory vegetation would be the fundamental way to improve the soil humus composition and stability. Source
Lu Y.-L.,Northwest Agriculture and Forestry University |
Lu Y.-L.,Ministry of Agriculture Key Laboratory of Plant Nutrition and the Agri environment in Northwest China |
Yang X.-L.,Northwest Agriculture and Forestry University |
Yang X.-L.,Ministry of Agriculture Key Laboratory of Plant Nutrition and the Agri environment in Northwest China |
And 4 more authors.
Chinese Journal of Applied Ecology | Year: 2015
In order to ascertain the effects of potassium fertilizer application periods on apple production, we conducted a field experiment and analyzed the differences in apple yield, fruit quality, potassium fertilizer use efficiency, and nutrient concentrations in leaves and fruits among treatments with differences in timing of potassium application. The results indicated that, compared with no potassium-applied treatment (CK), all potassium fertilizer application treatments significantly increased the apple yield by 4.3%-33.2%, meanwhile, it also obviously improved the fruit quality. In comparison with the application of 100% potassium fertilizer as a base, the application of 50% or 100% of potassium fertilizer at the fruit enlargement stage (the remaining 50% applied as a base or after flowering) significantly increased the apple yield by 20.5%-27.7% and improved the fruit quality. Compared with the application 100% potassium fertilizer at the stage of fruit enlargement, the evenly split application as base flowering stage and at the fruit enlargement stage not only contributed to a higher yield, better quality and higher potassium use efficiency, but also maintained a relatively stable potassium concentration level in leaves. However, the split potassium fertilizer application at the flowering and fruit enlargement stages resulted in the significant decrease in concentration of calcium in fruit, which would be negative to fruit quality. In conclusion, our research suggested that evenly split application of potassium fertilizer as a base and at the fruit enlargement stage was the suitable period for apple production in Fuji apple orchards in this region. ©, 2015, Editorial Board of Chinese Journal of Applied Ecology. All right reserved. Source