TITLE:
Chemical and Biological Properties of Apple Orchard Soils under Natural, Organic, Hybrid, and Conventional Farming Methods
AUTHORS:
Takamitsu Kai, Motoki Kubo
KEYWORDS:
Organic Farming, Soil Microorganisms, Soil Fertility, Agricultural Environment, Environmental Conservation
JOURNAL NAME:
Journal of Agricultural Chemistry and Environment,
Vol.9 No.3,
August
14,
2020
ABSTRACT: Apples in Japan are
generally cultivated under management systems that use chemical fertilizers and
synthetic chemical pesticides. However, the continuous use of these fertilizers
and pesticides damages the soil environment and reduces the number of soil
microorganisms. In this study, we compared the chemical and biological
properties of 12 soils from apple orchards in Aomori and Nagano Prefectures
under four types of management systems, namely, natural conditions, with no
cultivation, fertilizers, or pesticides; organic farming methods, using
organic materials and pesticides approved by the Japanese Agricultural
Standard organic certification system; hybrid farming methods, using a mix of
organic and chemical fertilizers; and conventional farming, using chemical
fertilizers and pesticides. Soil total carbon (TC), total nitrogen (TN), total
phosphorus (TP), nitrate-nitrogen (NO? 3), and available phosphoric acid
(SP) contents were generally found to be the highest where organic farming
methods were used. Similarly, bacterial biomass, nitrification (N) circulation
activity, ammonia (NH+
4) oxidation activity, nitrite (NO? 2) oxidation activity, and phosphoric
(P) circulation activity were the highest under organic farming, especially in
comparison with conventional farming. This study indicated that the differences
in apple sugar content, acidity, and sugar/acidity ratio between different orchard
management systems were due to different soil conditions, and soil conditions
under organic farming management system in apple cultivation increased bacterial
biomass while enhancing N and P circulation activity and high TC. On the other
hand, the soil of conventional farming has the lowest total number of bacterial
biomass and lowest material cycle such as N and P circulation activity. Analysis of the chemical and biological
properties of these orchard soils indicated that soil conditions under organic
farming management are the most suitable for increasing microbial numbers and
enhancing N and P circulation activity.