Recovery of nitrogen and phosphorus from livestock slurry with treatment technologies: A meta-analysis.

The livestock industry has developed rapidly in recent decades, but the improper treatment of livestock manure, especially slurry, causes environmental pollution. Treatment technologies are considered to be effective in alleviating nitrogen (N) and phosphorus (P) losses from livestock slurry. Here, we used published research data to conduct a meta-analysis of the recovery efficiencies of N and P of five mainstream treatment technologies, including ammonia stripping, air scrubbing, membrane filtration, microalgae cultivation and struvite crystallization.

[Temporal and spatial variation of the optimal sowing dates of summer maize based on both statistical and processes models in Henan Province, China].

Sowing date is one of the vital factors for determining crop yield. In this study, temporal and spatial variation of optimal sowing date of summer maize was analyzed by statistical model and the APSIM-Maize model in Henan Province, China. The results showed that average summer maize optimal sowing dates ranged from May 30 to June 13 across Henan Province with earlier sowing before June 8 in the southern part and later sowing from June 4 to June 13 in the northern part.