The content of available nitrogen (N) is generally low in coal mining subsidence reclamation soil. Appling organic and inorganic combined fertilizers can improve soil N fertility

whereas N availability is unclear after fertilization

especially in a new coal mining reclaimed soil. This experiment was conducted in coal subsidence reclamation soil of Shuiyu Coal Mining

which located in Xiaoyi City

Shanxi Province. The experiment included eight treatments which were three organic-inorganic combined treatments (application rate of chicken manure and chemical fertilizer was 1:1

and N at 100

150 and 200 kg/hm2

expressed with MF100

MF150 and MF200)

four single application of different amounts of chemical fertilizer nitrogen (N at 0

100

150 and 200 kg/hm2

expressed with IF0

IF100

IF150 and IF200)

as well as control (no fertilization

CK). We evaluated corn yield

aboveground nitrogen uptake

nitrogen use efficiency and mineral nitrogen content in soil profile after crop harvest

so that the suitable fertilization treatment and optimum nitrogen application rate were determined

which could provide scientific theoretical basis for reclaiming mining area soil in a way of high-yield and high-efficiency fertilization. The results showed that:(1) Under the condition of 150 kg/hm2 nitrogen fertilizer

the grain yield of MF150 was 12.45% higher than that of IF150 (P<0.05). Furthermore

there was no significant difference in grain yield among IF150

IF200 and MF200. (2) Nitrogen uptake of corn aboveground increased with the increasing of nitrogen application rate

while at the same nitrogen rate

the combined application treatment significantly increased nitrogen uptake by 39.45%~41.46% relative to single chemical fertilizer treatment (P<0.05). (3) At the same nitrogen rate

combined fertilizer treatment could significantly improve nitrogen recovery rate compared with single chemical fertilizer application. The partial productivity of nitrogen fertilizer in differentfertilization patterns showed a downward trend with the increasing of nitrogen application rate. The highest nitrogen agronomic efficiency (24.08 kg/kg) was observed in the IF100 treatment

and there was no significant difference between MF150 and IF100. However

at the same nitrogen rate

agronomic nitrogen efficiency of MF150 significantly increased by 49.56% compared with IF150. (4) After harvesting

mineral nitrogen content in 0-40 cm soil profile increased with soil depth

whereas at the same nitrogen rate there was no significant difference among different treatments. At 40-60 cm depth

the residual mineral nitrogen content of single chemical fertilizer application increased by about 18% compared with the combined fertilizer treatment. In a word

MF150 not only improved grain yield

nitrogen uptake and nitrogen use efficiency

but also reduced residual mineral nitrogen content in soil profile after plant harvest

hence MF150 could be used as a recommended fertilization treatment for this coal mining subsidence reclaimed soil or low-yield farmland similar to the soil type in this experiment.