10:45 〜 12:15
[AGE27-P02] Comparison of chemical and biological properties of soils between conventional or eco-friendly farming methods for Japanese pear cultivation
キーワード：ナシ栽培、環境保全型農業、都市農業、土壌微生物、窒素循環活性評価値
Japanese pear cultivation in Japan including Kawasaki, Tama and Inagi cities is faced with various problems, such as aging farmers, increasing area of abandoned land, and excessive reliance on synthetic pesticides and chemical fertilizers. Typically, synthetic pesticides are applied more than 32 times during a single growing season. The reliance on chemical fertilizers has significantly increased average yields (Kubo et al., 2016), due to their high-water solubility and ability to rapidly supply nutrients needed for plant growth. However, such heavy use of chemical fertilizers tends to lead to over-enrichment, which causes problems such as the destruction of ecosystems through the reduction and hardening of soil clusters, groundwater contamination, and a decrease in soil microorganisms. As a result, in recent years, the development of green food system strategies and the growing consumer need for food safety and security have led to a growing movement to reduce the use of synthetic pesticides and chemical fertilizers (Khairuddin et al., 2018). Therefore, in this study, we investigated the potential of eco-friendly agriculture systems by comparing the physical, chemical, and biological properties of soils of urban pear orchards under conventional and eco-friendly agriculture cultivation systems.
Soil samples were collected in July 2021 and 2022 from urban pear orchards in Kawasaki, Tama, Inagi cities, six orchards with pears cultivated under conventional agriculture six orchards using eco-friendly agriculture methods. Soil analyses were conducted to assess the potential for sustainable resource-recycling agriculture systems in these urban orchard soils. In the orchards under eco-friendly cultivation, which did not apply synthetic pesticides, eco-friendly methods were applied to try to control damage caused by pests. These included spraying male-attracting sex pheromones of lepidoptera in the air to disrupt communication between males and females. These methos reduce egg-laying density, of oriental fruit moths, leef beetles and sinkworms, as well as increases the numbers of phytoseiid mites that are the natural enemy of spider mite pests. Various physical, biological, and chemical soil parameters were measured at 10 cm, 20 cm, 30 cm, and 40 cm depths. Soil water content was measured using a pF meter and soil bearing capacity was measured using a cone penetrometer. Also, total bacterial counts, ammonia oxidation activity (NH4+ → NO2-), and nitrite oxidation activity (NO2- → NO3-) were also measured, and values were visually displayed on a triangular radar chart to evaluate the soil's ability to convert organic nitrogen to nitrate nitrogen as "nitrogen circulation activity. Furthermore, for plants to be able to absorb phosphoric acid, it is necessary for phytic acid (organic phosphate) to be decomposed into phosphoric acid (phytic acid decomposition activity). Therefore, the ability to convert phytic acid to phosphoric acid, was evaluated as the "phosphorus circulation activity.
The results of the soil fertility survey using the cone penetrometer showed that the fertility of the orchard soils was generally higher than that of the nearby soils. This may be because Japanese pear orchards are plowed less frequently than field soils, or because chemical spraying with a speed sprayer is conducted several times during the growing season in other field soils, or because the soil in tourist orchards is often subjected to compaction by trampling by visitors. The results of the analysis of soil chemistry, total bacterial count, nitrogen cycle activity, and phosphorus cycle activity are shown in Table.1. In terms of soil chemistry, the total carbon content was significantly higher in eco-friendly orchard soils than in the conventionally cultivated soils. In terms of soil biological properties, bacterial biomass and nitrogen circulation activity were significantly higher in the eco-friendly orchard soils than in the conventionally cultivated soils. Also, the eco-friendly orchard soils had greater bacterial biomass and more nitrogen circulation activity. In the future, we would like to improve the yield and quality of Japanese pears grown in sustainable resource-recycling agricultural systems.
This work was supported by the "Development and Improvement of Strategic Smart Agricultural Technologies" of the IISC and the Tokyu Foundation.
Soil samples were collected in July 2021 and 2022 from urban pear orchards in Kawasaki, Tama, Inagi cities, six orchards with pears cultivated under conventional agriculture six orchards using eco-friendly agriculture methods. Soil analyses were conducted to assess the potential for sustainable resource-recycling agriculture systems in these urban orchard soils. In the orchards under eco-friendly cultivation, which did not apply synthetic pesticides, eco-friendly methods were applied to try to control damage caused by pests. These included spraying male-attracting sex pheromones of lepidoptera in the air to disrupt communication between males and females. These methos reduce egg-laying density, of oriental fruit moths, leef beetles and sinkworms, as well as increases the numbers of phytoseiid mites that are the natural enemy of spider mite pests. Various physical, biological, and chemical soil parameters were measured at 10 cm, 20 cm, 30 cm, and 40 cm depths. Soil water content was measured using a pF meter and soil bearing capacity was measured using a cone penetrometer. Also, total bacterial counts, ammonia oxidation activity (NH4+ → NO2-), and nitrite oxidation activity (NO2- → NO3-) were also measured, and values were visually displayed on a triangular radar chart to evaluate the soil's ability to convert organic nitrogen to nitrate nitrogen as "nitrogen circulation activity. Furthermore, for plants to be able to absorb phosphoric acid, it is necessary for phytic acid (organic phosphate) to be decomposed into phosphoric acid (phytic acid decomposition activity). Therefore, the ability to convert phytic acid to phosphoric acid, was evaluated as the "phosphorus circulation activity.
The results of the soil fertility survey using the cone penetrometer showed that the fertility of the orchard soils was generally higher than that of the nearby soils. This may be because Japanese pear orchards are plowed less frequently than field soils, or because chemical spraying with a speed sprayer is conducted several times during the growing season in other field soils, or because the soil in tourist orchards is often subjected to compaction by trampling by visitors. The results of the analysis of soil chemistry, total bacterial count, nitrogen cycle activity, and phosphorus cycle activity are shown in Table.1. In terms of soil chemistry, the total carbon content was significantly higher in eco-friendly orchard soils than in the conventionally cultivated soils. In terms of soil biological properties, bacterial biomass and nitrogen circulation activity were significantly higher in the eco-friendly orchard soils than in the conventionally cultivated soils. Also, the eco-friendly orchard soils had greater bacterial biomass and more nitrogen circulation activity. In the future, we would like to improve the yield and quality of Japanese pears grown in sustainable resource-recycling agricultural systems.
This work was supported by the "Development and Improvement of Strategic Smart Agricultural Technologies" of the IISC and the Tokyu Foundation.