1.Nutrient Balances and Sustainability of Sugarcane Fields in
a
Mini-Watershed Agroecosystem of Northeast Thailand
Vidhaya TRELO-GES, Viriya LIMPINUNTANA, and Aran PATANOTHAI
土地利用の持続性の指標として、それらの圃場における主要な養分の収支を測
定した。タイ東北部の土地利用の持続性は、PとK収支が大きく負となっているこ
とが問題であると思われる。主な養分投入源は化学肥料で、主な搬出源はサトウ
キビの収穫だった。収穫前の火入れによる養分損失も大きかった。侵食された土
砂と水の量は大きかったが、それに伴う養分搬出は小さかった。高・中収量レベ
ルでは、高施肥の圃場であってもPKは大きく負の収支となった。このような状態
が続けば、土地利用の持続性が脅かされるので、養分収支を調整、改善する対策
が必要である。
2.Evaluation of Nutrient Availability of Sandy Soil in Northeast
Thailand
with Reference to Growth, Yield and Nutrient Uptake by Maize
Junta YANAI, Sayuri NAKATA, Shinya FUNAKAWA, Eiji NAWATA,
Roengsak
KATAWATIN, Thepparit TULAPHITAK and Takashi KOSAKI
土壌中の養分含量と植物の生育・収量および養分吸収との関係、そしてその規定
要因を明らかにし、さらに持続的な農業体系を確立するための合理的な管理技術
を提案するために、タイ東北部、コンケン大学内の圃場で圃場実験を行なった。
その結果、このトウモロコシ栽培体系では、Nが主な生育制御要因であった。大部
分の可給態NとPが深さ20cm以内の表層に存在していたので、この表層の侵食を防
ぎ、また土壌養分含量を維持する必要がある。
To everyone in Tropical Agriculture Laboratory,
On seminar of this week, Yuta Abe will give a presentation.
Thank you.
1.Nutrient Balances and Sustainability of Sugarcane Fields in a
Mini-Watershed Agroecosystem of Northeast Thailand
Vidhaya TRELO-GES, Viriya LIMPINUNTANA, and Aran PATANOTHAI
To determine the amount of nutrients in various sources of inputs
and
outputs for different type of sugarcane fields and to determine
the
balances of major nutrients in these fields as an indicator of
land-use
sustainability, the nutrients balances analyses of sugarcane
fields were
done.
Results of nutrient balance analyses indicated that land-use
sustainability
of these subsystems is under a threat from high negative balances
of PK
from current practices. The major source of nutrient input was
chemical
fertilizer and that of the output was cane yield. Nutrient losses
from
field burning before harvesting were also quite considerable.
Although the
amounts of eroded sediments and run-off water were substantial,
resulting
nutrient losses were rather small. Means to adjust nutrient
balance are
needed to improve their land-use sustainability.
2.Evaluation of Nutrient Availability of Sandy Soil in Northeast
Thailand
with Reference to Growth, Yield and Nutrient Uptake by Maize
Junta YANAI, Sayuri NAKATA, Shinya FUNAKAWA, Eiji NAWATA,
Roengsak
KATAWATIN, Thepparit TULAPHITAK and Takashi KOSAKI
To examine the relationship between the nutrient contents in soil
and
growth, yield and nutrient uptake by maze for a set of NPK
fertilizer
applicationsand to identify the limiting factors , and propose
rational
management practices for the agricultural system establish on the
marginal
sandy soil to be sustainable, a field experiment of maze was
carried out.
In this agroecosystem, N was most the dominant limiting factor
for the
production of maze.Considerable par of available NP was located
within 20cm
of soil, suggesting the importance of surface soil on nutrient
cycling
between soil and plant.Proper management for the maintainance of
the
sustainability of the system is needed.