Effect of cropping history on water retention characteristics of clayey paddy soil under low water potential conditions
2009
Adachi, K., National Agricultural Research Center, Joetsu, Niigata (Japan). Hokuriku Research Center | Yoshida, S. | Ohno, S. | Obara, H.
The water content and water potential of soil samples from paddy fields with varied cropping histories were measured under low water potential conditions. The relationships between the water content and the water potential were fitted to power equations. Analyses of the results for the fresh soils showed that the coefficient a (the water content at water potential of -1MPa) (CA) and the absolute value of the exponential index b (AB) of the fitted power equation was smaller in the soils under the cultivation of upland crops than the wetland rice. On the other hand, the difference in CA and AB for air-dried soil was not revealed between the soils under the upland crop cultivation and the soils under the wetland rice cultivation. The difference in CA for the fresh soil and for the air-dried soil and the difference in AB for the fresh soil and for air-dried soil were found to increase with continuous cropping of wetland rice, and decrease in response to continuous cropping of upland crops. These finding suggest these indices can presume cropping histories of rotational paddy fields.
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