The shaft tillage cultivation method is a no-tillage method for transplanting seedlings in an artificial macro-pore that facilitates placement of the crop roots much deeper than weeds. To test the effectiveness of this shaft tillage method on Chinese cabbage, column cultivation experiments were carried out. Then, water flow experiments were conducted to observe the process of root growth and water flow around an artificial macro-pore (8 mm diam., 20 cm long）under drip irrigation. Column experiments showed high density roots in the artificial macro-pore. The dry matter content of roots and leaves were found to be higher after use of the shaft tillage method as compared to the method without an artificial macro-pore. As determined in the water balance analysis of water flow experiments, most of the water uptake came from roots in the lower depth of the soil profile, suggesting important contributions of the high density roots to transpiration. Additionally, in the macro-pore experimental condition, we observed preferential water flow through the high density roots, indicating a shift to deeper sources of water for plant growth.

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An amaranthaceous halophyte, dwarf glasswort (Salicornia bigelovii), absorbs Fe and shows satisfactory growth under high pH. In this study, we investigated the strategy of Fe absorption by dwarf glasswort at high pH. In dwarf glasswort, there was no difference in the Fe concentration of shoots at pH 5.0 and pH 8.5. At pH 8.5 condition, dwarf glasswort drastically decreased the pH of the solution, and it absorbed more cations than anions for a short period. The observed acidification might have been due to secretion of protons to the rhizosphere due to absorption of Na. In contrast, the ability of spinach to decrease the solution pH was lower than that of dwarf glasswort. At pH 8.5, the ferric reductase (FR) activity of spinach decreased. However, dwarf glasswort showed similar FR activity at pH 5.0 and 8.5. It is possible that dwarf glasswort can maintain high FR activity at high pH. Thus, dwarf glasswort not only decreases external pH by secreting protons to make Fe available but it can also absorb Fe due to having a FR tolerant to high pH.

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