Soil biota (earthworm, nematode and soil surface fauna) data of organic, permaculture and conventional horticultural farms of Central Hungary

Description

Methods

Earthworms were counted in 25×25×25 cm soil cubes at 6 points on each farm in spring (21-23 May 2020) and autumn (11-13 September 2020) according to ISO 2006 standard. The excavated soil sample was hand-sorted on a plastic foil and earthworm indviduals were collected in coded jars. I recorded the earthworm counts in the field, then recounted them in the laboratory after the field day, separated adult and juvenile individuals, measured them, and then they were killed in 70% ethanol and left to stand in 4% formalin for one week. Finally, the individuals were placed back in 70% ethanol. Adult individuals were identified by external characteristics based on the descriptions of Csuzdi and Zicsi (2003) and Csuzdi (2007).

Soil samples for nematodes were taken with a cylindrical sampling device with open sides, using a so-called nematode sampling rod in spring (21-23 May 2020) and autumn (11-13 September 2020), in parallel with earthworm sampling. Composite samples were collected at 6 points in the study plots, from three subsamples (within 2 m2). About 100 g of soil per point were collected, of which 30 g per sample were weighed out in the laboratory, from which nematodes were extracted by gravity using the Baermann funnel method (Szakálas et al. 2015). I placed 2 layers of paper towel discs in the plastic filters and poured the soil sample onto them. The filters were placed in a glass funnel, pre-filled with distilled water and sealed at the bottom with a plastic clamp so that the filter was just in contact with the water surface. After 48 hours, I drained the distilled water into 50 ml Falcon centrifuge tubes, into which the nematodes migrated by gravity while the soil particles were trapped by the paper and filter. I then stored the samples in a refrigerator and counted the nematodes within two weeks, as most of them were still alive within this time, making counting easier and more reliable.

I used a soil trap method based on Császár et al. (2018) to survey the soil surface fauna on two occasions (May and September) in 2020. I placed 6 traps per farm at the preselected sampling points, and then collected them after 10 days. The soil traps consisted of a 500 ml clear plastic cup and a white plastic cover sheet, the latter fixed to the soil with 100 mm plastic sticks about 3-5 cm above the soil surface. I placed a 120 ml plastic container and a funnel made from the cut tops of plastic bottles. I used 70% ethylene glycol as a fixative medium. After 10 days, the containers were sealed with a screw cap and coded, stored in a cool box during collection and then at room temperature in the laboratory for further determination. In the laboratory, the samples were first poured into a larger Petri dish and then separated into groups using a forceps and placed in a smaller glass dish for microscopic determination, and the data were entered into a digital data base (Excel) and documented with photographs. Individuals were determined at taxon level (e.g. Araneae, Hymenoptera, Diplopoda, Collembola, Carabidae spp.), not species level.

Abstract

A summary of the PhD dissertation:

Our prevailing agricultural system violates sustainability criteria at many points and has a severe impact on natural ecosystems, as many studies and researchers have shown today. Several concepts have emerged on how to harmonize the maintenance of agroecosystems with production needs, one of them being sustainability and the more recent concept of ecosystem services. The objectives of the two concepts are very similar, as they both seek to balance the functions of agriculture and harmonize the impact of humans on the environment, but within a different conceptual framework. The common problem is how to measure, demonstrate, and communicate to society, the extent to which individual farms can meet these principles in practice. During my research, I started by analyzing this problem at the conceptual, and methodological levels but my main objective was to compare permaculture, organic and conventional farming systems along the two concepts based on empirical research. To this end, I conducted field studies in 15 small-scale, diverse horticultural farms (5-5-5 of each of the three types) in Pest and Nógrád counties in Hungary in 2020, related to soil, biodiversity or a specific ecosystem service (e.g. predation, decomposition, pollination). After the field and laboratory work, I interviewed the participating farmers in the first half of 2021, part of which was structured (to assess farming practices), while the second half was semi-structured questions to assess farmer attitudes. The data were first aggregated at farm type level and significant differences were statistically analyzed, while at the same time, the interviews were also aggregated and subjected to qualitative content analysis. I then aggregated the results along the four dimensions of sustainability and five ecosystem services and carried out a complex assessment. Finally, the data were thematically organized and subjected to principal component analysis to explore the interrelations between them.

 I found several significant differences between the farming systems, most of which supported the existence of positive ecological benefits of permaculture farming. I found that in the good governance dimension, permaculture performed best in terms of ethical farm management, while organic farming performed best in terms of professional management. In the environmental dimension, permaculture performed the best, with conventional performing the least. In the economic dimension, organic farming performed best, with permaculture performing the least. In the social dimension, organic farming performed best in terms of farmer welfare, while permaculture in terms of social innovation and participation; conventional farming underperformed both organic and permaculture. In all cases, permaculture had the highest potential for the studied ecosystem services (decomposition, global climate regulation, predation and pollination), as well as biodiversity as a characteristic of agroecosystem status. I have made several suggestions for further development of the research, emphasizing that it would be worthwhile to carry out more detailed, multi-year measurements with a larger sample size.