10:45 〜 12:15
[AGE27-P10] Enhancing Infiltration and Increasing Plant Biomass with Artificitial Macropore
キーワード：マクロポア、土壌炭素、植物バイオマス
Soil is the largest carbon reservoir on land, and fertile surface soils provide not only habitat for plants and animals, but also an important foundation for human agriculture. However, soil degradation has been progressing around the world in recent years. The Intergovernmental Panel on Climate Change (IPCC) has also noted that the frequency and intensity of heavy rainfall has increased since the 1950s over most of the land area, resulting in more intense rainfall and more severe drying even when total rainfall does not change significantly. Heavy rainfall is likely to cause surface runoff and subsequent soil erosion, which will have a significant impact on agriculture and livelihoods, especially in arid lands with poor vegetation. In this study, plant-rooted macropores were artificially created as a technique for proper infiltration and drainage of rainwater without destroying soil aggregates, and their effectiveness in promoting downward infiltration and organic matter storage was verified.
Two rainwater infiltration experiments were conducted: a rainwater infiltration experiment on a column with an 80-mm-diameter, 30-cm-high column filled with poor nutrient soil (masa soil) and an organic layer mixed with humus on the upper layer, and a plant cultivation experiment in which plants were planted and rain fell on the column. The rainfall intensity of the artificial rainfall device was set to 2 and 20 mm/h, and the total rainfall was the same, 3 mm/day, for 40 days. Two pore structures, one with artificial macropores (M) and the other without macropores (X), were also used for the experiment. The experiment was conducted using 12 columns in three replications for the four controls (2M, 2X, 20M, and 20X). Soil moisture content was measured hourly with a soil moisture sensor, surface runoff was measured in tubes near the soil surface, and downward drainage was measured in the bottom catch. After the experiment, soil samples were taken from the top, middle, and bottom at heights of 0-10, 10-20, and 20-30 cm to determine organic matter content by the ignition heat loss test. In the plant cultivation, cowpea was transplanted after germination. Maximum stem height (cm), number of leaves, above-ground dry matter weight (g), and root length (cm) were measured, in addition to moisture content, surface runoff, and downward drainage.
In the plant cultivation experiment, the lowest soil moisture was observed at 20M, where the most cowpeas grew and the highest plant biomass was observed. The highest plant biomass was observed at 20M, indicating that the plants grew better when the rainfall intensity was higher and the artificial macropores provided water more efficiently to the rhizosphere. However, there was no significant difference in infiltration, suggesting that improved aeration, rather than infiltration, promoted growth.
Two rainwater infiltration experiments were conducted: a rainwater infiltration experiment on a column with an 80-mm-diameter, 30-cm-high column filled with poor nutrient soil (masa soil) and an organic layer mixed with humus on the upper layer, and a plant cultivation experiment in which plants were planted and rain fell on the column. The rainfall intensity of the artificial rainfall device was set to 2 and 20 mm/h, and the total rainfall was the same, 3 mm/day, for 40 days. Two pore structures, one with artificial macropores (M) and the other without macropores (X), were also used for the experiment. The experiment was conducted using 12 columns in three replications for the four controls (2M, 2X, 20M, and 20X). Soil moisture content was measured hourly with a soil moisture sensor, surface runoff was measured in tubes near the soil surface, and downward drainage was measured in the bottom catch. After the experiment, soil samples were taken from the top, middle, and bottom at heights of 0-10, 10-20, and 20-30 cm to determine organic matter content by the ignition heat loss test. In the plant cultivation, cowpea was transplanted after germination. Maximum stem height (cm), number of leaves, above-ground dry matter weight (g), and root length (cm) were measured, in addition to moisture content, surface runoff, and downward drainage.
In the plant cultivation experiment, the lowest soil moisture was observed at 20M, where the most cowpeas grew and the highest plant biomass was observed. The highest plant biomass was observed at 20M, indicating that the plants grew better when the rainfall intensity was higher and the artificial macropores provided water more efficiently to the rhizosphere. However, there was no significant difference in infiltration, suggesting that improved aeration, rather than infiltration, promoted growth.