February 2023

Article: Cauliflower and leaves after cultivation on pig manure with or without incorporation: which cauliflower is tastier and how healthy is cauliflower leaf?

Four students from Inholland did research on the sensory properties and the ingredients of cauliflower. In addition to the cauliflower, the students also did research on the cauliflower leaves. The cauliflower leaves are often thrown away, reason to look at the possibilities to use these leaves!

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October 2021 – January 2022.
Article: “The influence of incorporating solid manure or not on the taste and nutritional value of cauliflower”.

Not incorporating solid manure is expected to have a positive effect on the soil and biodiversity compared to incorporating it, but what is the effect of a good quality soil on the quality of the cauliflower if we look at ingredients and sensory aspects?

In order to find out which form of fertilization has the most positive effects on the quality of cauliflowers, looking at the ingredients and sensory properties such as color, smell and structure, three students from Hogeschool Inholland conducted a study under the supervision of the Amsterdam Green Campus. The question was: does not incorporating manure affect the ingredients and sensory properties of cauliflower? And if so, is this a negative or a positive effect?

Download the article here: Article taste and nutritional value of cauliflower 2021

April 1, 2021 – May 30, 2021.
Thesis: “Effects of Minimal Tillage Management and Different Manure Types on Earthworm Populations in Dutch Cauliflower Fields”.
The international food production is increasing because of the global population growth. In order to meet the need for food in the world, the agricultural sector is under pressure. The demand for Intensive farming is growing rapidly, to have high crop profit on a short term. Intensive agriculture causes soil quality to deplete. The importance of focusing on soil improvement becomes more urgent. This can be achieved by changing agricultural methods. Techniques such as tillage and over-fertilization reduce biodiversity. The soil can no longer recover due to a nutrient deficiency. Tillage also affects underground life. There's a growing awareness that alternative and more sustainable agricultural methods must be found to prevent further deterioration of biodiversity. Non-incorporation of manure can contribute to the improvement of soil biodiversity because it leaves the home ground of organisms such as worms undisturbed. Worms improve the soil structure, stability and the conversion of soil organic matter (SOM). And play a crucial role in stimulating biodiversity. This research will therefore look at: How does the density and biomass of earthworms in Dutch marine clay soils vary over the season (1)? What is the correlation between earthworm types in relation to different manure types (2)? How does tillage affect the juvenile earthworm count, the food source of meadow birds (3)?

April 1, 2021 – May 30, 2021.
Thesis: “Effects of Minimal Tillage Management on Low-flying Insect Abundance and Meadow Bird Nests and Behavior in Dutch Cauliflower Fields”.
This study focuses on the effects of not incorporating straw-rich manure on low-flying insect populations and meadow bird nests and behaviour. To analyse insect populations, malaise traps were used that were emptied, dried, weighed and counted weekly before and after the application of manure, in order to subsequently measure whether there was a difference between incorporated and non-incorporated strips. Immediately after the application of manure, insect populations appear to be significantly higher on non-incorporated fields, most likely because the food supply is higher and more readily available. There is no significant relationship between bird nest numbers and incorporated or non-incorporated fields, but more nests were found on non-incorporated fields. It should be noted that the choice of bird nests by meadow birds is often more a habit than a conscious choice, so a direct relationship with incorporation or non-incorporation cannot be concluded. However, significantly more foraging took place on non-incorporated fields, probably because the insect supply on these fields is higher.

April 1, 2021 – May 30, 2021.
Thesis: “The impact of tillage practices on the aggregate stability of clay soil”.
This thesis focuses on the effect of tillage on the aggregate stability of soil. This research is based on the theory that tillage leads to lower aggregate stability and loss of topsoil organic matter, which can eventually lead to soil degradation. Tillage practices could then cause problems in agriculture, as they have significant detrimental effects on soil. In this research, four different types of organic matter (POXC, HWC, total organic matter and total carbon content) were examined and their relationship to aggregate stability. Soil samples were examined in a laboratory, using wet sieving methods, to calculate aggregate stability. These results were compared with previously collected data and discussed within the selected framework of sustainable agricultural practices. The results showed that tillage practices had no significant effect on aggregate stability within the indicated period of 5 months (P > 0.05). However, the different fields had significantly different aggregate stability (P < 0.0001). All four types of organic matter had a significant positive moderate correlation with aggregate stability in soil. We conclude that aggregate stability does not respond to short-term (< year) soil management strategies.

November 10, 2020 – March 30, 2021.
Thesis: “The effect of tillage and straw manure on nutrient leaching on marine clay soils”.
The thesis research focuses on the effect of ploughing and straw-rich manure on the leaching of nutrients to soil and surface water. The results of surface and soil water quality are described and discussed. The water samples were taken from fields with a marine clay soil where cauliflower is grown in Hem, the Netherlands. The cauliflower is grown on six plots of which three are tilled with ploughing (T) and three without ploughing (NT), all combined with straw-rich manure. Results of the sample analysis from the Skalar autoanalyzer are discussed with the help of literature to create guidelines for sustainable manure use.

March 30-July 10, 2020.

Thesis: “Will vis-NIR spectroscopy be the new method to measure aggregate stability?”.
Jhaleesa compared two models in the literature in which aggregate stability is calculated from pH, texture and organic content. It was compared with data that measure aggregate stability with a classical method (wet sieving) and Near InfraRed spectroscopy. She compared different datasets and interviewed Wim Reus. Her conclusion was that the current models are not so suitable for calculating aggregate stability, but that NIR spectroscopy is a good addition to the classical wet sieving method. The planned laboratory work could not continue due to COVID-19.

Aeres University of Applied Sciences Almere.
Literature review of the influence of spreading straw-rich manure above ground and not turning the soil on the soil structure, underground biodiversity (fungi, mites & earthworms) and above-ground biodiversity (mice and meadow birds).