Thesis subject

Impacts of agricultural management on crop yields, SOC, P and N/GHG losses

The Environmental Systems Analysis Group provides the possibility for students to do their thesis in collaboration with our group. The topics mentioned below are part of a larger theme. Please feel free to contact Prof De Vries, Dr Ros or Ms Young MSc (right) for more information.

Impacts of organic, mineral, and combined fertilizer nutrient management on soil organic carbon (SOC) changes: collection of recent data and improved meta-analytical modelling

  1. First-hand searching, screening, and collection of data reported by field studies;
  2. Integration into meta-analysis to analyze effects of management;
  3. Collection of data on site properties (co-variates) around Europe or comparing temperate and tropical zones: soil, climate, and crop properties as well as co-management;
  4. If time allows, can include multiple regression of co-variates on above-mentioned management impacts. Or a topic can be split into two: meta-analysis versus meta-regression;
  5. Can include subtypes of organic fertilizer and/or proportion of organic/mineral sources in combined fertilizer, or other amendments such as biochar.

Impacts of 4R principles of fertilizer application: right type, right amount, right time, right place) on soil nutrient (N and P) status, crop yield, nutrient use efficiency, and nutrient losses to environment: collection of recent data and meta-analysis

  1. First-hand searching, screening, and collection of data reported by field studies;
  2. Integration into meta-analysis to analyze effects of management;
  3. Collection of data on site properties (co-variates) around Europe or comparing temperate and tropical zones: soil, climate, and crop properties as well as co-management;
  4. If time allows, can include multiple regression of co-variates on above-mentioned management impacts;
  5. This topic can be split into different indicators: yield, nutrient use efficiencies, soil quality or nutrient losses.

Meta-regression of conservation agriculture practices (reduced tillage, soil cover, and crop rotation)  and site properties on (expected) soil organic carbon (SOC) changes

  1. Extraction of data from a pre-defined list of field studies and existing database;
  2. Collection of new field study data from recent months;
  3. Improvement of existing database and meta-regression model for SOC content and stocks;
  4. Insight in spatial variability of current and optimum SOC stocks (and impact of measures altering these stocks) in relation to local agroecosystem properties.

Meta-analysis and meta-regression, focus on crop yields. Effects of tillage, crop rotation, and/or nutrient management

  1. First-hand searching, screening, and collection of data reported by field studies;
  2. Integration into meta-analysis to analyze effects of management;
  3. Collection of data on site properties (co-variates) around Europe or comparing temperate and tropical zones: soil, climate, and crop properties as well as co-management;
  4. May include multiple regression of co-variates on above-mentioned management impacts.

Meta-analysis and meta-regression, focus on nutrient losses and GHG emissions to the environment: effects of tillage, crop rotation, and/or nutrient management

  1. First-hand searching, screening, and collection of data reported by field studies;
  2. Integration into meta-analysis to analyze effects of management;
  3. Collection of data on site properties (co-variates) around Europe or comparing temperate and tropical zones: soil, climate, and crop properties as well as co-management;
  4. May include multiple regression of co-variates on above-mentioned management impacts.

Investigation into field studies on the fate of phosphorus in agroecosystems: systematic literature review or meta-analysis work

  1. There are currently limited meta-analysis studies on P;
  2. This thesis could collect relevant recent field study data on the effects of management practice on P in crop, soil, and environment;
  3. Depending on data collection, a meta-analysis or quantification by other techniques could be performed.

Assessment of best management measures and stakeholder farming goals for EU27

  1. Systematic literature and database review on baseline/current management around Europe;
  2. Analysis of feasibility of applying management measures on arable land (e.g. no tillage is not possible on heavy soils);
  3. Assessment of the monetary costs involved in management practices and/or management shifts for farmers and society;
  4. Investigation into the willingness of farmers to shift management;
  5. Investigation of the preferences of stakeholders (farmers, policy-makers, etc.) for various goals: production (crop yield, cost), environment (nutrient use efficiency, minimizing N and P losses), climate mitigation (soil carbon storage);
  6. Can involve mapping of agricultural management situation of EU as well as link to Common Agricultural Policy (CAP).