TITLE:
Characterization of Orchard Fields Based on Soil Fertility Index (SOFIX)
AUTHORS:
Pitchayapa Pholkaw, Quoc Thinh Tran, Takamitsu Kai, Taiki Kawagoe, Kenzo Kubota, Kiwako S. Araki, Motoki Kubo
KEYWORDS:
Orchard Field, Soil Fertility Index (SOFIX), Bacterial Biomass
JOURNAL NAME:
Journal of Agricultural Chemistry and Environment,
Vol.9 No.3,
August
25,
2020
ABSTRACT: Soil samples from 139 agricultural orchard fields (apple, grape, tea, and
others) were analyzed using the soil fertility index. From these samples, an orchard
field database was constructed and the soil properties between orchard, upland,
and paddy fields were compared. The average value of bacterial biomass in the orchard fields
was 7.4 × 108 cells/g-soil, ranging from not detected (lower than
6.6 × 106 cells/g-soil) to 7.7 × 109 cells/g-soil. The
average values of total carbon (TC), total nitrogen (TN), total phosphorus
(TP), and total potassium (TK), were 24,000 mg/kg (2670 to 128,100 mg/kg), 1460
mg/kg (133 to 6400 mg/kg), 1030 mg/kg (142 to 5362 mg/kg), and 5370 mg/kg (1214
to 18,155 mg/kg), respectively. The C/N and C/P ratios were 19 (3 to 85) and 27
(2 to 101), respectively. Soil properties of the orchard fields were compared
with those of the upland and the paddy fields. The average value of bacterial
biomass in the orchard fields was almost the same as that in the upland fields
(8.0 × 108 cells/g-soil), but the number was lower than that in the
paddy fields (12.9 × 108 cells/g-soil). The average values of TC and
TN in the orchard fields fell between those in the upland fields (TC: 33,120
mg/kg, TN: 2010 mg/kg) and the paddy fields (TC: 15,420 mg/kg, TN: 1080 mg/kg). The relationship
between the bacterial biomass and TC in the orchard fields resembled that in
the upland fields. A suitable soil condition for the orchard fields was
determined as TC: ≥25,000 mg/kg, TN: ≥1500 mg/kg, TP: ≥900 mg/kg and TK: 2500 -
10,000 mg/kg. These
recommended values will be effective for the improvement of the soil quality in
the orchard fields by enhancing the number and activities of microorganisms.