Pedosphere 25(5): 737--748, 2015
ISSN 1002-0160/CN 32-1315/P
©2015 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effects of biochar and super absorbent polymer on substrate properties and water spinach growth |
FAN Ru-Qin1, LUO Jia1, YAN Shao-Hua1, ZHOU
Yun-Lai1 and ZHANG Zhen-Hua1,2 |
1Institute of Agricultural Resources and Environment,
Jiangsu Academy of Agricultural Sciences, Nanjing 210014
(China)
2School of Earth and Environment, The University of
Western Australia, Perth WA 6009 (Australia) |
| ABSTRACT |
| Most previous researches have focused on biochar
application in agricultural soils; however, limited
information is available concerning the effects of biochar
amendment on greenhouse substrate properties. A greenhouse
experiment was conducted to investigate effects of wheat
straw biochar (0--160 mL L-1) and super absorbent
polymer (SAP, 0.8 g L-1) on physical and chemical
properties of a substrate based on spent pig litter compost
and the growth of water spinach ( Ipomoea aquatica
Forsk). Total porosity, water-holding capacity, pH and
electrical conductivity (EC) of the substrate significantly
increased with increasing biochar rates, especially in the
substrate without SAP. The values of pH and EC were
significantly lower in the substrate with SAP than those
without SAP at the high biochar application rates (100--160
mL L-1). The germination rates of water spinach
decreased with increasing biochar rates when biochar was
added alone (76.9%--83.7%), whereas the rates increased
to 83.6%--85.8% when biochar was added in combination
with SAP. Growth parameters of water spinach and nutrient
uptake by shoots and roots increased with increasing
biochar rates and reached the maximum values at the biochar
rate of 100 mL L-1. There were significant cubic
relationships between the uptake of nutrients (N, P, and K)
and biochar rates, both with and without SAP addition. In
order to avoid negative effects on plant growth, the
biochar application rate should be controlled at an optimal
level (100 mL L-1). The SAP addition not only enhanced
the positive effects of biochar application on the
properties of the substrate, but also inhibited the
excessive rise of pH and EC following biochar additions,
which led to better plant growth and enhanced nutrient
uptakes by water spinach. |
| Key Words: amendment, electrical conductivity,
nutrient uptake, pH, total porosity, water-holding
capacity, water spinach, wheat straw |
| Citation: Fan, R. Q., Luo, J., Yan, S. H., Zhou, Y. L. and Zhang, Z. H. 2015. Effects of biochar and super absorbent polymer on substrate properties and water spinach growth. Pedosphere. 25(5): 737-748. |
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