Nutrient balances, soil quality and soil productivity in organic rice and vegetable crop rotations in West and Central Java, Indonesia

Self-sufficiency in food has been considered for decades as the most important item in agricultural policy in Indonesia, and still is at present. The green revolution in Indonesia has resulted in large increases in production, but at the same time has resulted in serious threats and problems. In recent years, no further increases in rice yield have been realised and yields in vegetable growing have declined despite massive and ever increasing agricultural inputs. Farmers have become extremely dependent on agricultural inputs; export goods are often refused because of unacceptable levels of pesticide residues; and there are increasing indications of serious nutrient and pesticide pollution of ground and surface waters. These problems are sensed by both farmers and policy makers, and have resulted in small scale farmers' initiatives on organic farming, and in the launching of campaign by government. However, these initiatives are scattered and lack of scientific background.

Therefore, there is an urgent need for development of scientific knowledge on sustainable farming systems. Organic farming initiatives have developed spontaneously over West and Central Java as a response to these problems, and have received attention and to some extent encouragement from the government. However, there is no structural framework to support these initiatives and little scientific research. Despite the lack of structural support, organic farming is growing steadily in West and Central Java, which proves its viability under the local conditions. There is an urgent need for basic research to further optimize organic production methods and to increase yields, and to safeguard soil and water quality over the long term.

This PhD research is therefore aimed at improving our understanding of nutrient cycling, nutrient use efficiency and soil quality in organic farming, as basic requirements for high and sustainable yields in these farming systems.

The general objectives of this research are to increase our fundamental understanding of how organic farming practices (in paddy rice and intensive vegetable growing) influence/alter the cycling and efficiency of nutrients (with the emphasis on Nitrogen), the chemical and biological soil quality, and ultimately the productivity (yield level and sustainability of yields) of farming systems.

Researcher: MSc. Okky Amalia
Period: 2012-2016
Financing body: VLIR project
Promoter: Prof. Stefaan De Neve