Monitoring fine root growth to identify optimal fertilization timing in a forest plantation: A case study in Northeast Vietnam

• Published in: PloS one Vol. 14; no. 11; p. e0225567
• Main Authors: Van Do, Tran, Thang, Nguyen Toan, Lam, Vu Tien, Van Thuyet, Dang, Trung, Phung Dinh, Quy, Tran Hoang, Phuong, Nguyen Thi Thu, Huyen, Ly Thi Thanh, Thinh, Nguyen Huu, Van Tuan, Nguyen, Duc, Dao Trung, Ha, Dang Thi Hai, Trung, Duong Quang, Luong, Ho Trung, Anh, Nguyen Thi Hoai, Nykiel, Patrick
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 25.11.2019; Public Library of Science (PLoS)
• Subjects: Acacia - growth & development; Biology and Life Sciences; Biomass; Case studies; Earth Sciences; Ecology and Environmental Sciences; Farmers; Fertilization; Fertilizers; Forests; Growing season; Monitoring; Nitrogen; Nutrients; Physiology; Plant Roots - growth & development; Plantations; Potassium; Production management; Productivity; Rainy season; Seasons; Soil sciences; Trees; Vietnam; Vietnam; United States > US; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0225567

Fertilizer is applied widely to improve the productivity of plantations. Traditionally, fertilization is conducted in spring and/or in the early rainy season, and it is believed to support the growth of planted trees in the growing season. Little attention to date has been paid on identification of the optimal timing of fertilization and fertilizer dose. In this study, application of the fine root monitoring technique in identifying optimal fertilization timing for an Acacia plantation in Vietnam is described. The study used two fertilizer doses (100 and 200 g NPK/tree) and three fertilization timings (in spring; in the early rainy season; and based on the fine root monitoring technique to identify when the fine roots reach their growth peak). As expected fertilization timings significantly affected growth and above-ground biomass (AGB) of the plantation. Fertilization based on the fine root monitoring technique resulted in the highest growths and AGB, followed by fertilization in the early rainy season and then in spring. Applying fertilizer at 200 g NPK/tree based on the fine root monitoring technique increased diameter at breast height (DBH) by 16%, stem height by 8%, crown diameter (Dc) by 16%, and AGB by 40% as compared to early rainy season fertilization. Increases of 32% DBH, 23% stem height, 44% Dc, and 87% AGB were found in fertilization based on fine root monitoring technique compared to spring fertilization. This study concluded that forest growers should use the fine root monitoring technique to identify optimal fertilization timing for higher productivity.