The objective of the present study was to explore the suitable combined pattern of tillage practice and nitrogen(N) rate for synchronously increasing the grain yield

water use efficiency and planting benefits in dryland wheat. In the dry year 2016-2017 and wet year 2017-2018

a field experiment was carried out in the typical dryland in western Henan province. In the experiment

the two tillage practices:Subsoiling tillage (ST) and conventional ploughing (PT)

were set as the main treatment

and the four N fertilizer application rates of 0

120

180 and 240 kg/hm2

expressed as N0

N120

N180 and N240

respectively

were set as secondary treatment. The subsoiling in ST was conducted about two weeks after the harvest of previous wheat every two years

and the ploughing in PT was carried out each year around late July to early August after once heavy rainfall. We tested the soil water content

yield and its components

water use efficiency and planting profit. Compared with PT

ST significantly enhanced rainfall fallow efficiency

and increased the water storage in 0-200 cm soil depth by 6.5%~11.7%

5.0%~8.5% and 4.7%~8.2% respectively at pre-seeding

anthesis and maturity. Therefore

ST significantly enhanced the spike numbers and numbers per spike in the wet year and the 1000-grain weight in the dry year

and thus increased the grain yield and economic return by 7.1%~17.8% and 5.5%~30.2% in the dry year

and increased the grain yield

water use efficiency

economic return by 10.2%~22.0%

3.0%~13.0% and 16.1%~35.1% in the wet year

compared with PT. With the increase of N rates

the rainfall fallow efficiency was significantly enhanced

resulting in that the water storage at pre-seeding was recovered in PT and significantly increased in ST. N180 was the optimal treatment in PT

and the grain yield

water use efficiency and economic return in N180 was 6.5%~43.9%

8.1%~36.1% and 12.4%~61.3% higher than those of the other N rate treatments. Under the ST

the optimal N treatment was N180 in the dry year while N240 in the wet year

and the grain yield

water use efficiency and economic return in the optimal treatment was 3.9%~67.9%

1.0%~54.1% and 3.6%~95.8% higher than those of the other N rate treatments. Above all

subsoiling at about two weeks after the harvest of previous wheat once every two years contributed to accumulating precipitation and increasing soil water storage

and thereby improving grain yield

water use efficiency and planting profit in dryland wheat

particularly with N rate at 180 kg/hm2 in the dry year

and with N rate at 240 kg/hm2 in the wet year. These results can provide a theoretical basis and technical reference for improving the grain yield

efficiency and profit in dryland wheat.