Americas and Oceania Group - International Plant Nutrition Institute

Potassium Application to Improve Yield and Quality of Chestnut
Project Leader: Li Jin-zhu, Hubei Academy of Forestry Science Institute of Economic Forests, No.370, Wuhan, Hubei.
E-mail: lijinzhu76@yahoo.cn
Project Cooperator: Luo Zhi-jian
Chestnut (Castanea mollissima Blume) is a local, dried fruit tree in Hubei province with planting area
of 354,000 ha and annual production of 125,000 t. The tree is widely distributed throughout the province
because of it’s strong adaptability and has a high value fruit. In order to increase chestnut yield and quality,
this project was conducted by the Hubei Academy of Forestry Science. Field experiments were carried out in
Macheng and Luotian counties of Hubei in 2011.
Results indicated that potash fertilization significantly increased chestnut yield. When N was applied at
200 kg/ha and P was applied at 120 kg P 2 O 5 /ha, increasing levels of K application (75, 150, 225, and 300
kg K 2 O/ha) increased chestnut yields to 5.9, 6.8, 7.2, and 7.5 t/ha, which were 12.8, 30.7, 37.8, and 43.4%
higher than yield without K application. The net incomes (USD) with varying levels of K application also
increased to 933, 2,312, 2,819 and 3,163/ha, respectively. Based on the results, the optimum K application
rate ranged from 150 to 225 kg K 2 O/ha was recommended for fruiting chestnut trees. With the optimum rate
of K application, chestnut yield can be increased on average from 1,600 to 1,900 kg/ha. Hubei-32
Soil Fertility Evaluation and Management Strategies for Garden Plants
Project Leader: Wan Kaiyuan, Chinese Academy of Science Wuhan Botanical Garden, Wuhan, Hubei.
E-mail: wankaiyuan@126.com
Project Cooperators: Tao Yong and Chen Shusen
Wuhan Botanical Garden, Chinese Academy of Science, has been carrying out a project since 2009 to
assess soil fertility and management strategies for successfully growing garden plants in Hubei province. For
this, a primary survey was done on garden plants in the province, and a total of 300 soil samples were taken
from the 10 main cities of Hubei and analyzed in 2010 and 2011.
Results from the survey and soil analysis indicated that the garden plant soil fertility was low in the 10
cities of Hubei, associated with compacted soils of bad structure. Both soil organic matter and available N
and P were low in the soils, while soil pH was rather high, when compared with farmland soils. Most of the
areas growing garden plants are not fertilized, although the recommended ratio of N:P 2 O 5 :K 2 O fertilization for
common garden flowers is 1:0.4:0.75 in Hubei. We conclude that some research and demonstration studies on
balanced fertilization in garden plants are urgently required. Hubei-33
Effect of Soil Fertility Evaluation on the Weed Succession Process
Project Leader: Wan Kaiyuan, Chinese Academy of Science Wuhan Botanical Garden, Wuhan, Hubei.
E-mail: wankaiyuan@126.com
Project Cooperators: Tao Yong and Chen Shusen
Ecological adaptation of plants is the result of mutual interaction between plants and their surrounding
environment. It reflects not just the adaptive ability of plants, but also the effect of environment on the plant
community. In agro-ecosystems, soil conditions tend to change under long-term fertilization that loads
natural selection pressure on weeds. And then the weed occurrence frequency, weed community component
and diversity, and weed seed bank were further influenced by reconstructed interspecific competition
relationships. To study the effect of soil fertility on weed succession, three experimental sites were established
in 2008 by Wuhan Botanical Garden, Chinese Academy of Science in Honghu and Yichang counties of
Hubei, and Fuzhou city of Fujian. A biodiversity survey of farmland weed communities at the sites was
conducted, including species, species coverage, and modular traits of some species in different seasons.
Results of the survey compiled in 2011 revealed that there were 54 species of 25 families, 49 species of 18
families, and 45 species of 20 families of weed in the three sites. Different soil and environmental conditions
had different weed species with different dominant species. For example, in Fujian, dominant species were
Biden pilosa, Erigeron annuus, Imperata cylindrical, and Rublaceae cordifolia, while in Honghu, dominant
species were Humulus scandens, Setaria faberii, Glycine soja, Artemisia annua, and Artemisia princeps, and
in Yichang, dominant species were Cynodon dactylon, Erigeron annuus, Lindernia ciliate, Setaria faberii, and
Bidens pilosa. Hubei-34
IPNI Interpretive Summaries 71