『Abstract
To evaluate the impact of human behavior (with regard food consumption,
waste disposal and farming method) on nitrogen flow, a field investigation
was conducted in six typical ecosystems in China. A number of
parameters for regional nitrogen balance models were identified
during the investigation. The results show that the average per-capita
daily protein intake is 107 g. While there is an insignificant
difference in total protein intake among the different ecosystems,
protein intake from all food groups, except for eggs, is significantly
different (P≦0.05). Differences in diet, along with those in socio-economic
conditions, reflect differences in the characteristics of the
ecosystems. Regarding per-capita annual potential nitrogen loading
from human excrement, a considerable difference exists between
the urban rich and the rural poor. In urban areas, approximately
1.02 kg N is returned to farmlands and 5.49 kg N is directly discharged
into rivers. In rural regions, on the other hand, approximately
4.33 kg N is returned to farmlands and 1.60kg N is directly discharged
into rivers. Furthermore, urea and mixed fertilizers constitute
the most common chemical fertilizers in the study area. Fertilizer
diversification is practiced in a range of agricultural lands,
paddy-fields and irrigated plains. In the oasis and paddy-field
agricultural systems, many of the agricultural by-products (e.g.,
straw) are burned or mixed with base-fertilizers and plowed into
the soil. In irrigated agricultural systems, over 70％ of agricultural
by-products are recycled as livestock feed. In most instances,
livestock excrement is directly reduced in the pasturelands or
reused in the fields as manure. Occasionally, as in the case of
large-scale breeding, excrements are usually abandoned.
Keywords: Ecosystem; Field investigation; Nitrogen flow; Food
intake; Farming method』
Introduction
Methodology
Investigation site and procedure
Content of the questionnaire
Data analysis
Results and discussion
Respondent characteristics
Identification of nitrogen-flow parameters related to dietary
habit
Dietary nitrogen intake by food group
Potential environmental nitrogen loading from human excrement
Potential river and soil nitrogen loading from farming method
Type and application method of chemical fertilizer
Agricultural by-product recycling
Livestock excrement recycling
Change in consumption and future food preference
Conclusions
Acknowledgments
Appendix
References