Study on the issues of farmers' income in major grain producing areas 并列题名：Study on the issues of farmers' income in major grain producing areas Study on compensation in major grain producing areas Research on farmland input by farmer households in major grain producing areas Study on the benefit compensation mechanism in the main grain producing areas 并列题名：Research on farmland input by farmer households in major grain producing areas 并列题名：Study on the benefit compensation mechanism in the main grain producing areas Research on the farmland rights confirmation in major-grain-producing-areas Study on climate change and food security in the major grain producing areas in China Benefit compensation mechanism of the major grain producing areas