The scale dependency of spatial crop species diversity and its relation to temporal diversity

Increasing crop species diversity can enhance agricultural sustainability, but the scale dependency of the processes that shape diversity and of the effects of diversity on agroecosystems is insufficiently understood. We used 30 m spatial resolution crop classification data for the conterminous United States to analyze spatial and temporal crop species diversity and their relationship. We found that the US average temporal (crop rotation) diversity is 2.1 effective number of species and that a crop’s average temporal diversity is lowest for common crops. Spatial diversity monotonically increases with the size of the unit of observation, and it is most strongly associated with temporal diversity when measured for areas of 100 to 400 ha, which is the typical US farm size. The association between diversity in space and time weakens as data are aggregated over larger areas because of the increasing diversity among farms, but at intermediate aggregation levels (counties) it is possible to estimate temporal diversity and farm-scale spatial diversity from aggregated spatial crop diversity data if the effect of beta diversity is considered. For larger areas, the diversity among farms is usually much greater than the diversity within them, and this needs to be considered when analyzing large-area crop diversity data. US agriculture is dominated by a few major annual crops (maize, soybean, wheat) that are mostly grown on fields with a very low temporal diversity. To increase crop species diversity, currently minor crops would have to increase in area at the expense of these major crops.

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Regional shifts of crop species diversity in rainfed and irrigated cultivation in Iran

10.21203/rs.3.rs-520570/v1 ◽

2021 ◽

Author(s):

Leila Jafaria ◽

Sara Asadi ◽

Ashkan Asgari

Keyword(s):

Species Diversity ◽

Agricultural Practices ◽

Crop Diversity ◽

Agricultural System ◽

Negative Effects ◽

Crop Species ◽

Production Risk ◽

Irrigated Crops ◽

Temporal And Spatial ◽

Weather Changes

Abstract Concerns about the negative effects of declining agricultural biodiversity due to modern agricultural practices and climatic constraints in various parts of the world, including Iran, on the sustainability of agricultural ecosystems are increasingly growing. However, the historical knowledge of temporal and spatial biodiversity is lacking. To identify the value and trend of crop diversity in Iran was used biodiversity indices based on the area under rainfed and irrigated crops and total from 1991 to 2018. The crop species diversity of irrigated cultivation was higher than the rainfed and total cultivations area. The Shannon and Simpson indices had experienced a constant trend, but species richness was increased, which was related to the rise in the area of some species in recent years. The area of wheat and barley had a significant impact on crop diversity so that Shannon diversity was reduced with their dominance. Overall, this study revealed that Iran's agricultural system relies on wheat and barley. We warn that by increasing the area of these crops and the prevalence of monoculture, the probability of damages increased due to external factors such as sudden weather changes or the spread of diseases and the important consequences of which will be instability and production risk in the future.

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Area And Diversity Of A Crop Reflects The Diversity Of Others

Journal of Agriculture and Environment ◽

10.3126/aej.v13i0.7581 ◽

2013 ◽

Vol 13 ◽

pp. 5-8

Author(s):

Bal Krishna Joshi ◽

Madhusudan Prasad Upadhyay ◽

Bimal Kumar Baniya ◽

Devendra Gauchan

Keyword(s):

Finger Millet ◽

Farm Size ◽

Baseline Survey ◽

Large Area ◽

Chi Square ◽

Crop Species ◽

Rice Landraces ◽

Genetic Resources Management ◽

Sponge Gourd ◽

High Diversity

This study was carried out to relate the diversity of one crop in terms of number of landraces and farm area with the diversity of other crop. Information collected during baseline survey of in-situ global project (1999) on three crops namely rice, finger millet and sponge gourd in Jumla, Kaski and Bara of Nepal were used. Farm area of each variety and number of landraces grown by sampled household were used for F-test, regression and chi-square analyses to test the diversity of one crop with respect to other. Households having large number of landraces of finger millet maintained large number of rice landraces. Households maintaining different landraces of sponge gourd and finger millet showed a relation with their farm area allotted to rice landraces. Households having large area for rice cultivation maintained a large number of rice landraces in all the sites. The analyses showed that the farmers growing diversity in one crop are more likely to grow diversity in other crops. Similarly, if area in a household allotted to a particular crop species is large, there is chance of growing high diversity of the crop species. Households having large farm size and maintaining high diversity of a crop species may be target farmers for genetic resources management. The Journal of Agriculture and Environment Vol:13, Jun.2012, Page 5-8 DOI: http://dx.doi.org/10.3126/aej.v13i0.7581

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Crop diversity is associated with higher child diet diversity in Ethiopia, particularly among low-income households, but not in Vietnam

Public Health Nutrition ◽

10.1017/s1368980021003281 ◽

2021 ◽

pp. 1-12

Author(s):

Erin E Esaryk ◽

Sarah Anne Reynolds ◽

Lia CH Fernald ◽

Andrew D Jones

Keyword(s):

Low Income ◽

Dietary Diversity ◽

Positive Association ◽

Household Wealth ◽

Crop Diversity ◽

Food Groups ◽

Crop Species ◽

Diet Diversity ◽

Household Level ◽

Functional Richness

Abstract Objectives: To examine associations of household crop diversity with school-aged child dietary diversity in Vietnam and Ethiopia and mechanisms underlying these associations. Design: We created a child diet diversity score (DDS) using data on seven food groups consumed in the last 24 h. Generalised estimating equations were used to model associations of household-level crop diversity, measured as a count of crop species richness (CSR) and of plant crop nutritional functional richness (CNFR), with DDS. We examined effect modification by household wealth and subsistence orientation, and mediation by the farm’s market orientation. Setting: Two survey years of longitudinal data from the Young Lives cohort. Participants: Children (aged 5 years in 2006 and 8 years in 2009) from rural farming households in Ethiopia (n 1012) and Vietnam (n 1083). Results: There was a small, positive association between household CNFR and DDS in Ethiopia (CNFR–DDS, β = 0·13; (95 % CI 0·07, 0·19)), but not in Vietnam. Associations of crop diversity and child diet diversity were strongest among poor households in Ethiopia and among subsistence-oriented households in Vietnam. Agricultural earnings positively mediated the crop diversity–diet diversity association in Ethiopia. Discussion: Children from households that are poorer and those that rely more on their own agricultural production for food may benefit most from increased crop diversity.

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Tobacco Production Practice of Smallholder in Bilate, Wolaita and Hawassa tobacco farms, Ethiopia

Advance in Biological Research ◽

10.26855/abr.2020004 ◽

2020 ◽

Vol 1 (1) ◽

pp. 23-28

Author(s):

Daniel Abebe ◽

Mekonnen Tadesse

Keyword(s):

Secondary Data ◽

Farm Size ◽

Southern Ethiopia ◽

Crop Species ◽

Policy Makers ◽

Secondary Sources ◽

Tobacco Production ◽

Production Practice ◽

Back Ground ◽

Good Relation

This study was conducted tobacco growing farmers’ house hold in the Wolaita ,Bilatte and Hawassa tobacco farms in Southern Nations, Nationalities and peoples’ Regional state, Ethiopia. The objective of the study was to investigate socioeconomic and technical factors that affect tobacco production smallholder tobacco producers at southern Ethiopia. In conducting the research, data relevant to the study were collected from both primary and secondary sources. Prior to interviewed back ground information and secondary data were collected from extension section of each tobacco development farm. Two peasant associations (PAs) were selected totally 30 sample farmers were randomly selected from each district based on tobacco production potential. Surveys were used to measured like area of plots with tobacco plants, household farming practiced at present and in the past, other crop species planted before, labor source, farm size and input. The findings from this study point to several recommendations for research, extension, and policy makers. The study recommended technologies to mitigate farmer’s labor shortage, regularly revised price of green tobacco price policies, good relation with local administrator and training of smallholder tobacco producers that would increase number of tobacco producers.

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Developing Herbicide-Tolerant Crop Cultivars: Introduction

Weed Technology ◽

10.1017/s0890037x00035909 ◽

1992 ◽

Vol 6 (3) ◽

pp. 613-614 ◽

Cited By ~ 8

Author(s):

Howard F. Harrison

Keyword(s):

Conservation Tillage ◽

Herbicide Tolerance ◽

Crop Damage ◽

Crop Species ◽

Crop Tolerance ◽

Minor Crops ◽

Herbicide Tolerant ◽

Private And Public ◽

Potential Benefits ◽

Margin Of Safety

In recent years considerable research in the private and public sectors has been directed toward introducing herbicide tolerance into normally susceptible crop species (9). Interest in developing herbicide-tolerant crop cultivars, clones, or hybrids (HTCs)3has been spurred by the reduction in the rate of discovery of new herbicidal compounds, the rising expense of developing new herbicides, and new tools of biotechnology that greatly increased our ability to develop HTC genotypes. Potential benefits of developing HTCs include: a) an increased margin of safety with which herbicides can be used with subsequent reduced crop losses due to herbicide injury, b) reduced risk of crop damage from residual herbicides from rotational crops, and c) introduction of new herbicides for use on normally susceptible crops. The last objective can be considered to be similar to breeding for resistance to diseases or insects. The most serious weed problems for a crop can be solved by developing crop tolerance to herbicides that control the weeds. This approach is particularly promising for minor crops for which new herbicide development is essentially lacking. However, the reluctance of herbicide manufacturers to register their products for minor crops may impede this approach. By developing tolerance to nontoxic, nonpolluting herbicides that are suitable for conservation tillage, the negative environmental effects of weed control can be reduced.

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