In order to provide references for adjustments of agricultural structures and crop arrangements

which aim to improve farmers' income within a commodity economy

optimal combinations of crop rotation are needed for agricultural development in Guanzhong plain.According to field test data

the economic value

land equivalent ratio(LRE)

biological yield

economic coefficient and the effects of rotation on soil nutrients were analyzed in different rotation systems.The crops tested included food crops of wheat(Triticum aestivum) and corn(Zea mays)

and vegetables of garlic(Allium sativum)

pepper(Capsicum)

eggplant(Solanum melongena) and celery(Apium graveolens)

which are commonly found in the plain.The results show that the terms of economic benefits and land production efficiency

the rotation system of wheat-maize was the worst one while the vegetables—vegetable rotation systems of garlic—pepper

garlic—eggplant

garlic—celery were the superior ones.From the ecological point of view focusing on biological yield and net organic yield

the value of wheat—maize was lower than the values of the vegetable—vegetable systems of garlic—pepper

garlic—eggplant

and garlic—celery

and was higher than the values of the crop—vegetable systems of wheat—pepper

wheat—eggplant

and wheat—celery.In the terms of effects on soil available nutrients and soil respiration rates

the crop—vegetable systems were better than the vegetable—vegetable rotation systems and the traditional crop rotation systems.Considering the values

geographic conditions and economic environments

the crop—vegetable rotation systems were suitable for the plain.As for the trials of this study

the rotation modes of wheat—pepper and wheat—eggplant were promising with a comprehensive consideration.