Organic manure as an alternative to crop residues for no-tillage wheat-maize systems in North China Plain

No-tillage (NT) can provide both environmental and economic benefits and has been recognized as a sustainable land use practice in many areas worldwide. NT has induced some concerns in the North China Plain (NCP), e.g. unstable crop yield and fodder shortage, with regards to the amount of crop residues retained on the soil surface. The objective of this study was to explore whether or not manure inputs are a viable alternative to crop residue in no-till wheat and maize rotation systems in NCP. Field experiments were initiated in October 2004 including three management operations: conventional tillage with residue removed (CTr), NT with crop residue left on soil surface (NTc), and NT with manure inputs (NTm); and two fertilizer application practices: splitting fertilizer inputs (SF) and concentrated fertilizer inputs (CF). These treatments were arranged in a randomized complete block design, with three replications, and continued over a 4-year period. Crop yield, soil properties and weed population were measured in a wheat-maize double crop system. Compared to CTr, NT had a trend of reducing wheat biomass and grain yield which reduced by 4% and 6%, respectively, for NTc, and 5% and 4%, respectively, for NTm. Tillage treatments, thus use of manure instead of residue, had no significant effects on maize biomass and yield. Fertilizer application practices had no significant effects on biomass and yield of both crops. Continuous NT for 4 years significantly increased the bulk density, soil water content, soil organic carbon (SOC) of the surface soil, but decreased the soil electrical conductivity (EC). The increase in SOC in NTm was higher than in NTc. Although soil EC decreased less in NTm than in NTc, the effects of soil EC could be neglected in the study. The NTc or NTm significantly inhibited the dominant weed in wheat field. The CF inhibited the flixweed (Descurainia sophia) growth compared to the SF. The manure inputs were found to be a viable alternative to crop residue in this NT wheat-maize system in the NCP. (C) 2013 Elsevier B.V. All rights reserved