Table 11. Summary of impacts to crops from tephra fall during the Shinmoedake eruption (based on accounts from farmers, Japan Agriculture and the Agriculture Improvement and Promotion Centre, as well as observations by the authors).
From: Observations of tephra fall impacts from the 2011 Shinmoedake eruption, Japan
Crop | Outdoor/Indoor | Stage of development | Impacts | Mitigation |
|---|---|---|---|---|
Spinach | Outdoor | Late stage of growth, ready for harvest | Tephra accumulated on leaf surfaces leading to acid damage and reduced photosynthesis | Spinach was cleaned by a micro-bubble washing method, but even after three washes some particles remained. Fresh products were therefore not able to be sold, but boiled and processed products were acceptable. |
Sweet Potato | Outdoor | Seedbed preparation, not yet planted | None | Farmers delayed planting by several weeks to avoid ashy conditions. |
Potato | Outdoor | Young plants, covered by non-woven cloth to provide temperature and moisture insulation | Seedlings damaged by falling coarse tephra; adherence of fine ash reduced photosynthesis and transpiration; smothering as protective cloth cover was tightened by tephra accumulation in windrow valleys | Tephra was removed from the top of windrows, cloth covers were replaced or strained cloth was cut and refastened. Additional fertiliser inputs were applied to promote stem and tiller development. |
Burdock Root | Outdoor | Young plants, covered by non-woven cloth to provide temperature and moisture insulation | The weight of tephra on the cloth suppressed growth | Farmers were recommended to remove tephra from the top of windrows and then cut the cloth in the valleys. The cut cloth was then fastened so as not to blow away. |
Onion | Outdoor | Well established | No damage reported, despite known sensitivity to low pH conditions | None required |
Taro | Outdoor | Seedbed preparation, not yet planted | n/a | Farmers delayed planting by several weeks to avoid ashy conditions. |
Radish | Outdoor | Seedbed preparation, not yet planted | n/a | Farmers delayed planting by several weeks to avoid ashy conditions. |
Shiitake Mushroom | Outdoor | Well established | Some damage in Takaharu but main growing area avoided tephra fall. Where affected, crop was highly vulnerable; could not be washed, therefore any tephra contamination resulted in 100% loss | None |
Tea | Outdoor | Early stage of crop cycle in the first of three to four harvests | Coverage of plants, leading to reduced photosynthesis and contamination of leaves | Self propelled sprayers were effective in removing tephra from leaves using compressed water. |
Carrot | Mix | Harvest and shipping period | Unknown | Unknown |
Sweet Pea | Indoor | Flowering | Flowers growth was affected due to reduced photosynthesis. In some instances marks developed on petals during shipping | Tephra removed from greenhouse roofs |
Rice | Outdoor | In fallow, several months after November harvest | n/a | None |
Peppers | Indoor | Well established | Vulnerable to low photosynthetically active radiation inputs in extreme cases of tephra coverage | Tephra removed from greenhouse roofs |
Cabbage | Mix | Well established | Affected by accumulation of tephra that penetrated inside the fronds and could not be removed by washing; any tephra contamination resulted in 100% loss | None |
Italian ryegrass (forage crop) | Outdoor | Becoming established; typically planted from end-October through to November, and harvested in April to May as silage or hay | Tephra <5 kg/m2 typically had minimal impact on grasses >5—10 cm tall; grass < 10 cm tall, were covered/smothered by tephra falls >5 kg/m2 and needed to be replanted; taller grass > 10 cm was able to grow through tephra of 5–10 kg/m2, but when harvested it was found to be contaminated and therefore not acceptable | When crops did not grow, tephra was removed from the field and replanted. Grass contaminated by tephra was typically not used for feeding animals; however, hay was acceptable due to vigorous shaking associated with baling. |