Elissa Brown, Ben Sullender, Amy Teller
Assessing Biodiversity
It is essential that farms not only consistently produce the crops that we depend on but also promote the vitality of the surrounding ecosystems. In order to assess the ecological impact of farmer practices, we developed a scoring system to quantify one component of ecological sustainability: biodiversity. Biodiversity is essential to any successfully functioning agroecosystem. Biodiversity can be defined as “all species of plants, animals and microorganisms existing and interacting within an ecosystem, and which play important ecological functions such as pollination, organic matter decomposition, predation or parasitism of undesirable organisms” (Nicholls and Altieri 2004), suggesting a complex relationship between every organism involved. To get at this underlying complexity, it makes sense to take on a multifaceted approach to most accurately quantify the sustainability of a particular agroecosystem’s biodiversity (Benton, 2003).
For this assessment, our holon is the land contained within the farm boundary. To score biodiversity within this holon, we consider factors which are grouped into two ecological indicators, Crop Biodiversity and Associated Biodiversity. Crop Biodiversity takes into account factors that influence the biodiversity of the productive, planned plant communities within the farm, which are the crops that are planted deliberately in the farmer’s fields. These factors include Number of crop species, Number of crop families, Evenness of crop species, Type of rotation, and Type of cropping system. Associated Biodiversity is based on factors that influence the biodiversity of all other organisms found within the farm borders, including non-crop plants and wildlife. These factors include Impact of insecticides, Impact of herbicides, and Quality, Extent, and Arrangement of non-cropped habitat. Based on our research, the factors involved in determining Crop Biodiversity and Associated Biodiversity account for all types of biodiversity found on a farm and all farmer choices that have a significant impact on farm biodiversity. The scores for each factor are used to calculate the two ecological indicator scores, which are then considered to evaluate each farm’s Total Biodiversity. For more information about how we chose our factors and indicators as well as a detailed description of our scoring method, please see the Appendix.
We visited 17 farms, 11 in China and 6 in southern Minnesota, where we spoke to the farmers, made our own observations, and ultimately collected the data that we used in our biodiversity assessment. The following table shows the scores each farm received for each factor, for both indicators, and for its total biodiversity. The scores each farm received are discussed in more detail after the table.
Chinese Farms
Duan Farm – 13.2 acres
Total Score: 6.2 (Crop Biodiversity: 7.7, Associated Biodiversity: 4.7)
Mr. Duan’s farm is a CSA that provides to 10 families and feeds 50 people from his own family. He has 13.2 acres of land, of which 0.16 acres is in greenhouses. Duan receives a good score for Crop Biodiversity, which was only hurt by his score of 5 for intercropping. His greenhouses were intercropped, but much of his cropped land is in larger fields that were not intercropped. He receives a lower score for Associated Biodiversity even though he doesn’t use pesticides because he had very little non-cropped habitat. Overall, Duan’s farm is respectable in terms of biodiversity, but improvements could be made, especially in the areas of habitat and intercropping.
Ji Farm - 0.96 acres
Total Score: 6.5 (Crop Biodiversity: 9.1, Associated Biodiversity: 4.0)
Mr. Ji’s farm is also a CSA that provides to 150 families in Beijing and consists of 6 greenhouses that are about 0.16 acres each. Ji receives a very admirable score for Crop Biodiversity because of his extensive use of intercropping, his rotation practices and the 20 crops from 16 families that he grows. He is hurt by his low Associated Biodiversity score, which he receives because he has no non-cropped habitat at all. His land is contained within the greenhouses. Mr. Ji does not use pesticides. An improvement in habitat is all Mr. Ji needs to get a great score for biodiversity, but this may not be feasible on his land.
Ai Farm – 3.3 acres
Biodiversity Score: 2.8 (Crop Biodiversity: 1.2, Associated Biodiversity: 4.4)
Mr. Ai is a small farmer who grew only corn and barley on 3.3 acres up until 7 years ago. Since the government required that much of his land be reforested, he now subsistence farms on 0.6 acres. He receives a low score for Crop Biodiversity because he only grows two crops, has no rotation and corn is grown as a monoculture on 85% of his land. His Associated Biodiversity score is also low because he has very little habitat, but he does not use pesticides. Mr. Ai receives a low score for biodiversity overall which he may not have the capacity to improve.
Little Donkey Farm – 8.2 acres
Biodiversity Score: 7.1 (Crop Biodiversity: 8.6, Associated Biodiversity: 5.6)
Little Donkey Farm is a CSA owned by a village collective and operated by 5 managers, some interns and students from Renmin University in Beijing. Little Donkey receives a very high score for Crop Biodiversity because they grow 40 types of vegetables, have a rotation and intercrop the vegetables. Little Donkey’s score for Associated Biodiversity is lower even though they do not use pesticides. This is because Little Donkey has only a little bit of non-cropped forested habitat on a few sections of the farm. Little Donkey earns a good score for biodiversity and could improve mainly in the area of non-cropped habitat.
Liu Farm – 2 acres
Biodiversity Score: 5.1 (Crop Biodiversity: 5.1, Associated Biodiversity: 5.1)
Mr. Liu’s farm is one of the most “conventional” Chinese farms that we visited. He sells to distributors, and people in Chengdu purchase his products. He receives a mediocre score for Crop Biodiversity because he grows rice, corn and oranges on most of his land for most of the year and grows vegetables only in the winter on some of the 0.5 acres that are in rice the rest of the year. He intercrops and rotates only the vegetables, not the rest of his crops. Mr. Liu also receives an average score for Associated Biodiversity. This is because he uses pesticides that are toxic to non-target plants and insects, birds and some mammals. However, 0.7 acres of Mr. Liu’s 2 acres are forested, non-cropped habitat due to the Chinese government’s reforestation policy. This helps improve Mr. Liu’s score for associated biodiversity, although there is not much variety in non-cropped habitat. This “conventional” Chinese farm receives a much better biodiversity score than “conventional” American farms like Pahl’s.
Gao Farm – 1.8 acres
Total Score: 6.8 (Crop Biodiversity: 9.2, Associated Biodiversity: 4.4)
The Gaos are one of 7 families who cooperate in a CSA that supplies to urban residents of Chengdu. Crop Biodiversity is good, as they grow a wide variety of crops, 20 species that are from 12 crop families. Crops tend to be planted in small patches, providing the benefits of intercropping, and a good rotation system is used. However, their score is hurt by their lack of Associated Biodiversity, as very little non-cropped habitat exists within the extents of their farm – only small field borders and plots rented by urbanites that go untended and become overgrown. No pesticides or herbicides are used.
Wong Farm – 0.6 acres
Total Score: 5.7 (Crop Biodiversity: 7.1, Associated Biodiversity: 4.4)
The Wongs run their own CSA that provides vegetables to 15 Chengdu families. Their Crop Biodiversity score is lower, as they grow a less diverse assortment of crops, 12 species from 5 crop families, and their rotation practices are not ideal since each year for four months mostly rice is grown and no land is ever left fallow to rest. Many plots are intercropped though. Their Associated Biodiversity score is low since the only non-cropped habitat within the farm is found in small field borders, but no pesticides or herbicides are used.
Zhuyeqing Tea – 264 acres
Total Score: 4.2 (Crop Biodiversity: 1.9, Associated Biodiversity: 6.5)
Although five varieties of tea are grown on this giant tea farm, Crop Biodiversity suffers from the lack of multiple families and the impossibility of rotation and rest. Their Associated Biodiversity score is much higher. This is because the farm does also grow some fruit trees for the purpose of increasing biodiversity though, and about 30% of the land, dispersed throughout the hills, is forested. However, some low toxicity herbicides are used around the tea and sticky flags are placed in the tea plants with the purpose of killing all insects that come into contact with the flags.
Lei Farm – 1.7 acres
Total Score: 6.1 (Crop Biodiversity: 3.7, Associated Biodiversity: 8.5)
The Leis grow tea to sell to visitors on Emei Shan and a small amount of vegetables to feed themselves. They get a low score on Crop Biodiversity because one variety of tea plant dominates their farm – only 5% of their land is used to grow other vegetables. This system does not allow for rotation or intercropping. Associated Biodiversity, however, is very good, as a large portion of their land is habitat that is native to the mountain.
Lo Yu Farm– 8.2 acres
Total Score: 8.8 (Crop Biodiversity: 9.1, Associated Biodiversity: 8.5)
Lo Yu has a CSA that sells to residents and restaurants in Chengdu. His Crop Biodiversity is good, as he grows 70 different vegetables with significant intercropping and good rotation practices, leaving 20% of his land fallow each year. He also receives a good Associated Biodiversity score because all land that doesn’t receive sufficient sunlight is growing native trees and plants instead. 25% of his land is non-cropped habitat that is dispersed throughout the farm. He does not use pesticides or herbicides.
Duofu Farm – 198 acres
Total Score: 5.9 (Crop Biodiversity: 7.2, Associated Biodiversity: 4.6)
Duofu Farm is a corporate organic farm that rents land from village farmers and employs them to work for the corporation. Duofu receives a good score for Crop Biodiversity because they grow a wide assortment of crops, 50 species. However, Duofu uses minimal intercropping and only rotates the vegetable plots. Duofu does not receive a very good score for Associated Biodiversity because there is little to no habitat preservation. The farm is planning to reduce their already-dwindling wild acreage. No herbicides are used and BT pesticide is sprayed 3-5 times per season.
American Farms
Gardens of Eagan – 100 acres
Total Score: 6.1 (Crop Biodiversity: 6.7, Associated Biodiversity: 5.5)
Gardens of Eagan is an organic farm that sells its produce to co-ops. They receive a good score for Crop Biodiversity because they grow a diverse assortment of crops, 15 species, but they devote a large portion of acreage to two main crops, corn and broccoli. A complex rotation system is used, spanning the course of several years and using different types of cover crops. However, very few acres are intercropped. Gardens of Eagan receives a mediocre score for Associated Biodiversity because although they have a good amount of permanent habitat, it is poorly arranged into large blocks and riparian barriers. Four main pesticides and herbicides are applied as needed to specific areas of the farm.
Pahl’s – 1200 acres
Total Score: 4.3 (Crop Biodiversity: 6.5, Associated Biodiversity: 2.2)
Pahl’s, a large-scale corporate conventional farm, consists of many geographically separate farms that grow different crops. For Crop Biodiversity, Pahl’s grows 16 crops, but the majority of acreage is devoted to sweet corn. Different rotations are used depending on the crop, each rotation system lasting several years and including cover crops. Pahl’s receives a very low score for Associated Biodiversity because aside from insignificant windbreaks, there is no land kept in permanent habitat. Many different types of pesticides and herbicides are used, each targeting a separate crop.
Earthen Path – 14 acres
Total Score: 9.7 (Crop Biodiversity: 10.0, Associated Biodiversity: 9.5)
Earthen Path grows vegetables for its CSA members and to sell to co-ops in southeastern Minnesota. This farm receives an excellent Crop Biodiversity score because a wide variety of crops, 100 species from 20 crop families are grown, usually in long rows to take advantage of the benefits of intercropping, and with a long rotation cycle. Associated Biodiversity is also excellent, as 64% of the land is high-quality non-cropped habitat. However, even this score could be improved if low toxicity pesticides were not used. According to our assessment, Earthen Path is the highest scoring farm for Total Biodiversity and also for both indicators. The farmer practices at Earthen Path could be considered aspirations for farmers who need to make improvements in biodiversity.
Lutteke Organics – 1000 acres
Total Score: 6.3 (Crop Biodiversity: 4.7, Associated Biodiversity: 7.8)
The Lutteke farm is an organic farm that produces dairy products and eggs. They grow their own feed for their dairy cows and we are assessing those fields. Lutteke Organics receives a mediocre score for Crop Biodiversity. They grow only 4 crops, corn, alfalfa, oats, and soybeans, but these crops are grown in relatively even distributions by area. Also, a 2-3 year rotation is used, with land remaining as cropland for one year before being returned to pasture. Several different types of cover crops are used, including red clover, winter rye, and oats. Lutteke Organics receives a good score for Associated Biodiversity because they have non-cropped habitat, arranged along the perimeter of fields, building sites, ditches, and the river. No herbicides or pesticides are used.
Big Woods – 79 acres
Total Score: 8.3 (Crop Biodiversity: 9.2, Associated Biodiversity: 7.5)
Big Woods Farm is a CSA that grows a wide variety of crops, 20 species from 20 different families, which are evenly distributed over the field acreage. A multiyear rotation using cover crops is used. Some land is left in permanent pasture, and the majority of the acreage has some intercropping. Therefore, Big Woods receives an excellent score for Crop Biodiversity. In terms of Associated Biodiversity, 4 acres are left as permanent habitat, arranged so that they form continuous riparian barriers. They are well dispersed and contain native plant species. This score is hurt slightly by the practice of applying BT, pyganic, and Entrust to a small percentage of the cropland once or twice a season.
Schrader Farms
Biodiversity Score: 2.9 (Crop biodiversity: 1.8, Associated biodiversity: 4.0)
Schrader Farms is a conventional corn and soybean farm. They receive a very low score for Crop Biodiversity because they only grow two crops in monoculture and have a 2 years corn, 1 year soybeans rotation. The Schraders earn a better score for Associated Biodiversity because they have 70 acres of wooded land with native species, continuous non-cropped areas and some riparian barriers. However, they also use toxic pesticides on all of their land. The lack of crop diversity is the biggest setback for biodiversity at Schrader Farm.