Abstract: We investigated the effects of different conservation tillage technologies on the ecological benefits, crop yield and net economic benefit of degraded brown soil, based on the conservation tillage experimental research platform of Lao Cheng Town, Changtu County, Liaoning Province. The treatments included conservation tillage technology with in-situ straw recycling \[conventional ridge tillage without straw return (57 cm uniform ridges), wide double row with one space (57-114 cm) and narrow double row with one space (45-105 cm) no-tillage with straw strip mulching\] and integrated planting-breeding with chicken manure recycling technology \[fertilizer reduction combined with chicken manure under wide double row with one space and no-tillage with straw strip mulching conditions: conventional NPK (control), 75% NPK+3000 kg·hm^-2 chicken manure, 50% NPK+6000 kg·hm^-2 chicken manure, 25% NPK+9000 kg·hm^-2 chicken manure, and 0% NPK+12000 kg·hm^-2 chicken manure\]. Soil physicochemical properties and crop yields were measured. The results showed that, compared to conventional ridge tillage without straw return, double row with one space and no-tillage technologies with straw strip mulching for three years increased soil moisture retention, carbon sequestration and soil fertility (no statistical significance, P>0.05). These technologies significantly increased corn yield and economic benefit by 12.7% and 20.0% (P<0.05), with economic benefit being increased by 3277.9 and 4276.4 yuan·hm^-2·a^-1 for wide and narrow double row with one space no-tillage with straw strip mulching, respectively. Compared with the conventional application amount of NPK, different amounts of NPK reduction combined with chicken manure for three years significantly increased soil ecological benefits (P<0.05). Among the combinations, 50% NPK combined with 6000 kg·hm^-2 chicken manure and 25% NPK combined with 9000 kg·hm^-2 chicken manure had the best effects, with soil carbon sequestration potential, fertility increase potential, comprehensive ecological benefits, and corn yield being enhanced by 9.2%, 8.2%, 6.2%, and 15.2%, respectively. The economic benefits of these two chicken manure substitutions were enhanced by 3759.7 and 3406.3 yuan·hm^-2·a^-1 compared to conventional NPK application amount. In conclusion, conventional NPK fertilization combined with straw in-situ cycling conservation tillage technology and integrated NPK reduction with chicken manure recycling can increase crop yield and net economic benefit by improving soil ecological benefits, indicating that these conservation measures can be demonstrated and promoted in Changtu County.

Key words: degraded brown soil, conversation tillage, organic manure, ecological benefit, economic benefit