Horticulture and Orchards as New Markets for Manure Valorisation with Less Environmental Impacts

David Fangueiro,Paula Alvarenga,Rita Fragoso

doi:10.3390/su13031436

Abstract

Animal manure management is a real challenge to minimize environmental impacts and ensure that this valuable material is efficiently used in a circular economy context. One of the main limitations for larger use of animal manure as fertilizer is the availability of land to receive it in an area close to the farm. Indeed, animal manure is traditionally used for cereals and animal feed growth, but the soil area occupied with these crops might not be enough to receive all the manure produced and/or part of this soil might have nutrient contents, namely phosphorous, that do not permit further application of manure. Hence, extra land used for other agricultural activities might be an option. The main objective of the present review was to analyse the constraints and solutions to increase the use of manure in horticulture and orchards. Emphasis was given to the legal framework for manure utilization in the EU that might stimulate or restrain such a solution. The main characteristics of manure that might limit or stimulate manure reuse were also described, and the potential of some treatments to valorise manure was analysed. Several examples of alternative uses of manure in horticulture and orchards were examined, and the society and farmers’ acceptance of the proposed solution was addressed.

Highlights

The increase in the world population of ~33% to 2050 should be followed by a 70%increase in food demand worldwide [1,2]
The present review aims to analyse the constraints and solutions to increase the use of manure in horticulture and orchards, with special emphasis on the legal framework for its utilization in the European Union (EU), the main characteristics of manure that might limit or stimulate its reuse, and the potential of some treatments to its valorisation
Its main objective is to revise the nitrate directive, allowing the use of N-rich sub-products from animal manure, with the same conditions as those imposed on mineral N fertilizers [35], which are based on soil nutrients status and crop requirements

Summary

Introduction

The increase in the world population of ~33% to 2050 should be followed by a 70%. increase in food demand worldwide [1,2]. The size of livestock farms increased, moving to industrialized farms, concentrated in the same area and, generally, with low soil availability This is especially the case for pig [7] and poultry [8] productions, while the dairy and beef sector, despite a trend to intensification in some regions, continues to be more extensive [9,10]. Direct application of raw manure in an area close to the farm is the common practice in most EU regions, and it remains the best option (cheaper, lower energy use) Another option to minimize the environmental impacts of animal manure is its treatment, such as solid–liquid separation [18] or acidification [19]. An exhaustive presentation of alternative uses of manure in horticulture and orchards is compiled and, a key parameter for the success of this solution, society and farmers’ acceptance, is addressed

Legal Framework to Use Manure in the EU

Treatment Strategies to Increase Manure Acceptance for Farmers and Society

Alternative Uses for Manures or Manure-Based Products

Farmers and Society Acceptance

Findings

Conclusions