Optimising Cropping Techniques for Nutrient and Environmental Management in Organic Agriculture

Abstract

Depth and architecture of root systems play a prominent role in crop productivity under conditions of low water and nutrient availability. The subsoil contains high amounts of nutrients that may potentially serve for nutrient uptake by crops including finite resources such as phosphorus that have to be used in moderation to delay their exhaustion. Biopores are tubular shaped continuous soil pores formed by plant roots and earthworms. Taproot systems especially those of perennial legumes can make soil nutrients plant available from the solid phase and increase the density of vertical biopores in the subsoil thus making subsoil layers more accessible for succeeding crops. Density of larger sized biopores is further enhanced by increased abundance and activity of anecic earthworms resulting from soil rest and amount of provided feed. Nutrient rich drilospheres can provide a favorable environment for roots and nutrient uptake of subsequent crops. Future efficient nutrient management and crop rotation design in organic agriculture should entail these strategies of soil fertility building and biopore services in subsoil layers site specifically. Elements of these concepts are suggested to be used also in mainstream agriculture headlands, e.g. as 'Ecological Focus Areas', in order to improve soil structure as well as to establish a web of biodiversity while avoiding constraints for agricultural production.

Effects of Continuous Vertical Soil Pores on Root and Shoot Growth of Winter Wheat: A Microcosm Study

“…It has been suggested that increasing CVP densities by cultivating taprooted crops or promoting anecic earthworms can be an element of strategies for soil fertility building [47]. Our study revealed that the effects of large vertical pores on crop growth largely depend on environmental conditions.…”

The ‘Invisible’ Subsoil: An Exploratory View of Societal Acceptance of Subsoil Management in Germany

“…13), it is no longer practiced widely in Germany. Detrimental effects to soil structure, soil functions and soil life (2,4,5,6,7,8,16,17) Heavy machines necessary and lots of energy (3,6,8,10,11,12) In no case acceptable (1,2,3,4) Numbers in parentheses indicate the No. of stakeholders and farmers who mentioned the respective aspect.…”

“…Improved structure, biological activity, infiltration capacity (1,2,4,5,7,8,9,14,16) Economically not attractive to most farmers due to limitations on usage of the crop and opportunity costs (1,2,4,5,6,7,8,10,11,12,13,14,15,16,17) Effective remediation option for compacted soils, suitable for most soil types (1,3,5,6,7,8,9,10,13,16,18) Wealth of experience (3,7,10) Good component in the crop rotation, increased yield in the following years when applied for two years or more (1, 3, 4, 8, 9, 10, 12, 14, 17, 18) Effective method to reduce compaction without the risk of recompaction (5,7,9) The positive impression of alfalfa is in large part based on a pool of positive experience with this technique in Germany. Biological subsoil loosening by means of alfalfa is a widely known concept among farmers and stakeholders, who were all aware of the deep rooting potential of the alfalfa plant.…”

“…Suitable for heavily compacted sites, primarily under driving lanes and headlands (1,2,3,4,5,7,11,12,13,14,18) Risk of re-compaction, complete loss of soil structure or shift compaction into deeper layers (2,5,7,10,16,17) Accepted on dry soils/ light and sandy (1,2,10,12,13,16,18) High efforts and costs, heavy machineries and high energy input is needed (3,6,7,8,10,12,15) Only in combination with biological activation, catch cropping or diverse crop rotation (2,4,6,7,10,12,18) Not suitable for subsoils with stones and drainage systems (14,15) Short-sighted solution, without implementing any changes in the farming system that aim to prevent new compaction, lead to the need to repeat the procedure again after a short period of time (1,5,6,7) Subsoiling requires heavy machinery and a high input of energy to loosen deep soil layers, making it an intense operation that involves high efforts and costs. One rather scep...…”

“…In this context, researchers have begun to look more systematically at subsoil functions/the role of subsoil for soil functions and to develop and investigate new strategies of mechanically or biologically intervening in subsoils that aim to tap the subsoil as a resource [10][11][12][13][16][17][18]]. Yet how relevant, feasible, and acceptable are different methods for subsoil management as a strategy that can contribute to the sustainable management of soils and to securing long-term agricultural yields?…”