Research in the Department of Urban Horticulture and Planting Design

Project start: 01.07.2023
Project end: 30.06.2026
Sponsor: Bundesministerium für Umwelt, Naturschutz und nukleare Sicherheit

The preservation and planting of urban green, especially trees, play a crucial role in the adaptation of cities to global heating, as they provide natural cooling. Larger trees transpire up to 500 litres of water per day. Shade and evaporative cooling reduce the effect of urban heat islands. However, road salt, soil compaction and pollutants stress urban trees. Heat and drought intensify, so that new plantings often fail to grow and existing trees increasingly die before they reach a size that has an impact on the city's climate. Alternative tree substrates could provide a remedy, and also improve the infiltration of water from heavy rainfall events. One promising approach are biochar macadam substrates (PMS), i.e. defined mixtures of rock gravel, plant charcoal and compost. After compaction, the crushed stone results in a passable but pore-rich structure that creates space and aaeration for root growth and which are capable of absorbing high levels of precipitation. The production of the biochar also locks up biomass carbon over decades to millennia (=carbon sinks, i.e. carbon (dioxide) removal). PMS were developed in Stockholm and are so far only used in Sweden, Austria and Switzerland. The goal of "Black2GoGreen" is to create a network of municipalities, municipal enterprises, associations as well as manufacturers of biochar and biochar (tree, green-roof) substrates to transfer knowledge about already implemented solutions to Germany.

Project start: 01.05.2014
Project end: 31.12.2018
Sponsor: Federal Ministry of Education and Research, Federal Ministry for Economic Cooperation and Development

African indigenous leafy vegetables (ALV) play a significant role in food security in Africa. They are mainly produced by small -scale farmers and are marketed or traded locally, regionally or even internationally. Currently, the magnitude of postharvest losses of AVLs in Kenya can reach up to 50%, depending on the product. These losses are attributed to various factors including; inadequate application of plant nutrients and water supply during production, rapid physiological deterioration and microbiological decay of products during transport, storage and marketing. Inadequate harvest techniques and facilities for storage and transport, insufficient processing and preservation methods, insufficient hygiene conditions in the markets as well as poor infrastructure aggravate the problems, causing massive losses along “the field to consumer” chain. The overall aim of this project is physiological and molecular investigation of African leafy vegetables (ALVs) for quality assurance and loss reduction in post-harvest management. Pre-harvest endogenous Carbohydrates in some plants like Pelargonium spp and Portulaca grandiflora and have been reported to play a role in post-harvest storability by decreasing ethylene sensitivity hence reducing leaf senescence (Rapaka et al., 2007; Rapaka et al., 2006).The carbohydrates serve as basic source of energy and initial substrate for the microbes involved in fermentation. Fermentation is one of the preservation methods in which the nutrients are preserved, and therefore vegetables can be used for a longer time. The study specific aims incudes;- determining carbohydrates at different development stages, different irrigation regimes and Soil nutrients, different harvesting method and daytime, to study changes during storage and correlation of different levels to ethylene production, storability duration, and fermentation rates.