Artificial macropore installation and no-tillage practice in subtropical sugarcane field to conserve water and organic matter in soils

Kanako Oka, Thanh Long Bui, Yasushi Mori, Kazutoshi Osawa, Akira Hoshikawa

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Artificial macropore introduction and no-till practices were conducted in the subtropical red soil of a sugarcane field on Ishigakijima Island, Japan, to increase the storage of soil water and carbon. The examined fields were suffering from heavy rain, typical of the subtropical climate, the intensity of which is increasing because of climate change. Heavy rain causes surface runoff and soil erosion, which decreases sugarcane yield. Soil particles were being delivered directly into the sea, potentially affecting coral reefs. Therefore, the storage of soil water and soil carbon is crucial for protecting the natural subtropical environment. Artificial macropores with bamboo fibers were installed at 1 m intervals to enhance vertical infiltration. In addition, no-tillage agriculture with the retention of plant residues was conducted to protect the surface soil from the impact of heavy rain. Field management trials were conducted under no-tillage with/without macropores (NT-M and NT-X, respectively) and conventional tillage with/without macropores (CT-M and CT-X, respectively). Rainfall, surface runoff, soil erosion, soil moisture, and total soil carbon were measured. As a result, the macropore installation fields (CT-M and NT-M) had greater soil moisture contents than the fields without macropore installation (CT-X and NT-X). The average soil moisture values of each profile revealed that NT-M retained more soil water than CT-X (p < 0.01). Moreover, the calculated soil profile total carbon decreased under NT-X, CT-M, and CT-X. This is normal for a tropical climate with a relatively high temperature. However, the NT-M treatment showed an increase in soil carbon by +0.45 t-C·ha−1·yr−1. This value corresponded well with that of conservative practices in such agriculture fields. This result indicates that macropore installation in combination with no-tillage practices increases the total carbon in the soil profile, even in tropical climates. We recommend macropore installation with no-tillage practices with plant residue retention as an effective measure for enhancing the retention of soil water and soil carbon.
Original languageJapanese
Pages (from-to)93-103
Number of pages11
JournalJ. Jpn. Soc. Soil Phys.
Publication statusPublished - Apr 12 2022

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