Application rate and composting method affect the immediate and residual manure fertilizer value in a maize–rice–rice–maize cropping sequence on a degraded soil in northern Vietnam

Abstract

A field experiment was carried out in northern Vietnam to investigate the effects of adding different additives [rice (Oriza sativa L.) straw only, or rice straw with added lime, superphosphate (SSP), urea or a mixture of selected microorganism species] on nitrogen (N) losses and nutrient concentrations in manure composts. The composts and fresh manure were applied to a three-crop per year sequence (maize–rice–rice) on a degraded soil (Plinthic Acrisol/Plinthaquult) to investigate the effects of manure type on crop yield, N uptake and fertilizer value. Total N losses during composting with SSP were 20% of initial total N, while with other additives they were 30–35%. With SSP as a compost additive, 65–85% of the initial ammonium-N (NH₄-N) in the manure remained in the compost compared with 25% for microorganisms and 30% for lime. Nitrogen uptake efficiency (NUE) of fresh manure was lower than that of composted manure when applied to maize (Zea mays L.), but higher when applied to rice (Oriza sativa L.). The NUE of compost with SSP was generally higher than that of compost with straw only and lime. The mineral fertilizer equivalent (MFE) of manure types for maize decreased in the order: manure composted with SSP > manure composted with straw only and fresh manure > manure composted with lime. For rice, the corresponding order was: fresh manure > manure composted with SSP/microorganisms/urea > manure composted with lime/with straw alone. The MFE was higher when 5 tons manure ha⁻¹ were applied than when 10 tons manure ha⁻¹ were applied throughout the crop sequence. The residual effect of composted manures (determined in a fourth crop, with no manure applied) was generally 50% higher than that of fresh manure after one year of manure and compost application. Thus, addition of SSP during composting improved the field fertilizer value of composted pig manure the most.

Keywords:

• compost
• crop yield
• nitrogen uptake efficiency
• mineral fertilizer equivalent.

Acknowledgments

We thank Mrs Tran Thi Thu Trang, Nguyen Thi Loc, Cao Thi Hai and Nguyen Thi Tam in the Midland Centre of Soils and Fertilizers Research (Hiep Hoa, Bac Giang) for their help and support in the field experiment. We thank Mr Nguyen Van Chien, Mrs Nguyen Thi Lan and all staff of the Central Analytical Laboratory (Soils and Fertilizers Research Institute, Hanoi, Vietnam) for technical support in analysing samples. This study was funded by the Council for Development Research (RUF) – Danish Ministry of Foreign Affairs via the research project SUSANE (Sustainable, sanitary and efficient management of animal manure for plant nutrition; Project No.J.nr.104. Dan.8.L.722).