Biological transformation characteristics of N and P in different polytunnel greenhouse vegetable soils;

Contents of heavy metal elements in soils of vegetable greenhouses different in age;

Experimental study on the changes of nutrient salt and trace element contents in soils of vegetable greenhouse for different cultivation years;

Research on Analytical Method and Environmental Behavior of PAEs in Vegetable Greenhouse;

Taking Cangzhon of Hebie Province as an example,based on the meteorological data from 1970 to 2005,an analysis is made of meteorological factors affecting greenhouse vegetables in winter,such as extreme minimum air temperature,winter average temperature,severe temperature drop,fog,scant sunlight,gale,heavy snow and so on.

In order to study the meteorological service index of the Greenhouse vegetables for frozen injury, and provide better services for the rural economy meteorology.

Variations of Total Salt and Salt Ion Composition in Vegetables Greenhouse Soil in Suburbs of Qinhuangdao City;