4Lehrsch G A, Sojka R E, Westermann D T. Nitrogen placement, row spacing, and furrow irrigation water positioning effects on corn yield [ J ]. Agronomy Journal, 2000, 92 ( 6 ) : 1266 - 1275.
5Skinner R H, Hanson J D, Benjamin J G. Root distribution following spatial separation of water and nitrogen supply in furrow irrigated corn[J]. Plant and Soil, 1998, 199:187-194.
6Elrick D E, French L K. Miscible displacement patterns on disturbed and undisturbed soil cores[J]. Soil Sci. Soc. Amer. Prec. , 1966, 30:153-156.