The effect of the adjusted density on the steady yield and water use of spring maize covered with film in dry land was discussed in order to provide a basis for the high and stable yield of spring maize in rain-fed area of dry land. The experiment was conducted from 2014 to 2017 in the Loess Plateau

Zhenyuan

Gansu (107°39'E

35°30'N) in a split plot design. The compact and dense and high-yield spring maize variety Xianyu 335 was used as the test material

55 cm and 75 cm were set up with two kinds of row spacing covering planting

6.0×104 plants/hm2

7.5×104 plants/hm2

9.0×104 plants/hm2 and 10.5×104 plants/hm2 4 planting density levels. The soil moisture of 0-200 cm soil layer in different spring maize growth period was measured by drying method

and the grain yield and soil profile water change of continuous cropping spring maize were studied in the Loess Plateau. The results showed that under the experimental design distance

there is a low moisture area between 0-200 cm in the soil profile of 55 cm and 75 cm in the dry year

and the lowest water content of two row spacing 40-200 cm soil layer is in the section of 160 cm soil layer

the soil moisture content of 55 cm row spacing is 8.9%

the soil moisture content of 75 cm row spacing is 8.7%. The soil moisture of 20-120 cm soil layer changed more sharply with the influence of precipitation and plant growth water consumption. Regardless of the annual precipitation pattern

the soil dry layer was not produced in the 0-200 cm soil depth under two row spacing. Compared with the 55 cm row spacing

the distance to the low humidity area of the 75 cm row spacing enlarged in varying degree with the change of years

but there was no significant difference in the same density water consumption of the 7.5×104~10.5×104 plants/hm2 under the two rows. The 4 years average yield of the 75 cm row spacing was higher than that of the 55 cm row spacing

and better stable yield was achieved in 9.0×104 plants/hm2 and below planting density. The yield increased from low to high density by 2.2%

5.8%

4.1% and 3.0% respectively

while the average water use efficiency increased by 1.1%

5.9%

0.3% and -1.5% respectively

and the yield of the same density and water use efficiency in different row spacing were the same. The research showed that in the Loess Plateau

55 cm and 75 cm row spacing with 7.5×104 plants/hm2 planting density for continuous cropping has stable yield

and will not lead to soil water deficit to produce dry soil layer

which is the ideal planting pattern of continuous cropping stable plant spacing.