Development of a rapid soil phosphate fertility test and improvement of potato productivity under volcanic ash soils in the tropics

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K15948
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 41050:Environmental agriculture-related
• Research Institution: Obihiro University of Agriculture and Veterinary Medicine
• Principal Investigator: Kinoshita Rintaro 帯広畜産大学, グローバルアグロメディシン研究センター, 助教 (70793678)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 土壌 / リン肥沃度 / バレイショ / 熱帯 / 黒ボク土 / リン酸吸収係数 / 簡易分析法

Outline of Final Research Achievements

Potato is a popular crop to be cultivated in the highlands of the tropics but the yields are low. Volcanic ash soils are wide spread in these areas and low phosphate fertility is thought to be the major cause of low yield. This study assessed soil characteristics and phosphate fertility of the potato growing fields of Kenya. We also developed rapid soil phosphate fertility testing method. The phosphate fertility of potato growing fields were variable depending on the fields and more than 80% of the fields showed optimum to excessive available phosphate. This is likely caused by large inputs of animal manure. We developed a rapid phosphate absorption coefficient testing method using air dry soil moisture content.

Free Research Field

土壌学

Academic Significance and Societal Importance of the Research Achievements

熱帯の火山灰土壌ではリン肥沃度が低いことが作物収量の制限因子であると考えられていたが、調査対象地域ではリンは適正か過剰な地点が多いことが明らかとなった。リン過剰が作物収量や品質だけでなく、周辺環境に及ぼす影響の評価も重要であると考えられた。土壌のリン固定力は土壌のリン肥沃度に影響を及ぼすため重要である。本研究から、土壌のリン固定力を土壌が風乾後に含む水分含量を評価することで推定可能であることが明らかになった。