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| Titel |
Effects of implementing organic rice-duck integrated farming on reducing agricultural diffuse pollution around Dianshan Lake in the western suburbs of Shanghai |
| VerfasserIn |
Xue-Feng Hu, Qing Teng |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250137796
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| Publikation (Nr.) |
 EGU/EGU2017-623.pdf |
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| Zusammenfassung |
| Located in the western suburbs of Shanghai, Dianshan Lake is a major source of Huangpu
River, a mother river flowing through the metropolitan area. To protect the drinking water
source areas, the development of any industries and livestock breeding is forbidden around
the lake since the early time. However, the lake is still under a eutrophic state throughout the
year. In 2013, for example, total N and total P in the lake water were 2.98 mg L−1 and 0.17
mg L−1 on average, respectively. It is believed that 72.2% of N and 73.1% of P in
the lake come from agricultural diffuse pollution. The areas surrounding the lake
include six towns and are all low-lying in landform. There are 5975 ha paddy fields at
the six towns, making up 33.1% of total farming land in the areas. According to
our questionnaires to local farmers at Jinze Town, one of the six towns, for the
consecutive five years, the amounts of N and P2O5 applied within the rice growing
season under the conventional rice farming are 336.6 kg ha−1 and 76.9 kg ha−1 on
average, respectively, and those lost through leaching and runoff are 15.42 kg ha−1
and 3.55 kg ha−1 on average, respectively. Further study estimated that the total
amounts of N and P2O5 applied around the lake within the rice growing season are
2.01×106 kg year−1 and 4.59×105 kg year−1, respectively; those lost through leaching
and runoff are 0.99×105 kg year−1 and 0.23×105 kg year−1, respectively; those
discharged from the fields into the lake are 0.99×104 kg year−1 and 0.23×104
kg year−1, respectively. Our study also indicated that the amount of pesticides
and herbicides discharged from the paddy fields at the six towns into the lake is
approximately 1.67×104 kg year−1. Appreciately, the agricultural diffuse pollution from the
paddy fields surrounding the lake have posed severe threat to the lake. The field
experiments indicated that raising ducks in the paddy fields within the rice growing season
can not only highly reduce weed hazards and incidence of rice pests and diseases,
but also significantly improve soil fertility. The rice plants co-cultured with ducks
grow healthily, if not applying any herbicides and pesticides, which is conducive
to establish organic rice farming. It is estimated that the total amounts of N and
P2O5 discharged from the paddy fields into the lake would reduce by 75.8% and
95.2%, respectively, and the potential pollution from pesticides and herbicides can be
totally prevented, if implementing the organic rice-duck integrated system at the
six towns surrounding Dianshan Lake. This will contribute greatly to improve the
water quality of the lake. Moreover, the organic rice produced by the rice-duck
integrated system is five times higher in prize than the conventional rice, and the
ducks ecologically growing in the fields are four times higher in prize than the
intensively cultivated ones. This will also be beneficial to increase farmers’ incomes. |
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