scholarly journals Leveraging Parrondo's paradox for sustainable agriculture

Author(s):  
Chaitanya Gokhale ◽  
Nikhil Sharma

Abstract Rotating crops is a sustainable agricultural technique that has been at the disposal of humanity since time immemorial. Switching between cover crops and cash crops allows the fields avoids overexploitation due to intensive farming. How often the respite is to be provided and what is the optimum cash cover rotation in terms of maximising yield schedule is a long-standing question tackled on multiple fronts by agricultural scientists, economists, biologists and computer scientists, to name a few. Dealing with the uncertainty in the field due to diseases, pests, droughts, floods, and impending effects of climate change, is important to consider when designing the cropping strategy. Analysing this time-tested technique of crop rotations with a new lens of Parrondo's paradox allows us to improve upon the technique and use it in synchronisation with the burning questions of contemporary times. By calculating optimum switching probabilities in a randomised cropping sequence, suggesting the optimum deterministic sequences and judicious use of fertilisers, we propose methods for improving crop yield and the eventual profit margins for farmers. Overall we also extend the domain of applicability of the seemingly unintuitive paradox by Parrondo, where two losing situations can be combined eventually into a winning scenario.

Author(s):  
Robert P. Larkin

Crop rotations and the inclusion of cover crops and green manures are primary tools in the sustainable management of soil-borne diseases in crop production systems. Crop rotations can reduce soil-borne disease through three general mechanisms: (1) serving as a break in the host-pathogen cycle; (2) by altering the soil physical, chemical, or biological characteristics to stimulate microbial activity and diversity; or (3) directly inhibiting pathogens through the release of suppressive or toxic compounds or the enhancement of specific antagonists. Brassicas, sudangrass, and related plant types are disease-suppressive crops well-known for their biofumigation potential but also have other effects on soil microbiology that are important in disease suppression. The efficacy of rotations for reducing soil-borne diseases is dependent on several factors, including crop type, rotation length, rotation sequence, and use of the crop (as full-season rotation, cover crop, or green manure). Years of field research with Brassica and non-Brassica rotation crops in potato cropping systems in Maine have documented the efficacy of Brassica green manures for the reduction of multiple soil-borne diseases. However, they have also indicated that these crops can provide disease control even when not incorporated as green manures and that other non-biofumigant crops (such as barley, ryegrass, and buckwheat) can also be effective in disease suppression. In general, all crops provided better disease control when used as green manure vs. as a cover crop, but the addition of a cover crop can improve control provided by most rotation crops. In long-term cropping system trials, rotations incorporating multiple soil health management practices, such as longer rotations, disease-suppressive rotation crops, cover crops, and green manures, and/or organic amendments have resulted in greater yield and microbial activity and fewer disease problems than standard rotations. These results indicate that improved cropping systems may enhance productivity, sustainability, and economic viability.


Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 840 ◽  
Author(s):  
Ahmed Laamrani ◽  
Paul R. Voroney ◽  
Aaron A. Berg ◽  
Adam W. Gillespie ◽  
Michael March ◽  
...  

The impacts of tillage practices and crop rotations are fundamental factors influencing changes in the soil carbon, and thus the sustainability of agricultural systems. The objective of this study was to compare soil carbon status and temporal changes in topsoil from different 4 year rotations and tillage treatments (i.e., no-till and conventional tillage). Rotation systems were primarily corn and soy-based and included cereal and alfalfa phases along with red clover cover crops. In 2018, soil samples were collected from a silty-loam topsoil (0–15 cm) from the 36 year long-term experiment site in southern Ontario, Canada. Total carbon (TC) contents of each sample were determined in the laboratory using combustion methods and comparisons were made between treatments using current and archived samples (i.e., 20 year and 9 year change, respectively) for selected crop rotations. Overall, TC concentrations were significantly higher for no-till compared with conventional tillage practices, regardless of the crop rotations employed. With regard to crop rotation, the highest TC concentrations were recorded in corn–corn–oats–barley (CCOB) rotations with red clover cover crop in both cereal phases. TC contents were, in descending order, found in corn–corn–alfalfa–alfalfa (CCAA), corn–corn–soybean–winter wheat (CCSW) with 1 year of seeded red clover, and corn–corn–corn–corn (CCCC). The lowest TC concentrations were observed in the corn–corn–soybean–soybean (CCSS) and corn–corn–oats–barley (CCOB) rotations without use of cover crops, and corn–corn–soybean–winter wheat (CCSW). We found that (i) crop rotation varieties that include two consecutive years of soybean had consistently lower TC concentrations compared with the remaining rotations; (ii) TC for all the investigated plots (no-till and/or tilled) increased over the 9 year and 20 year period; (iii) the no-tilled CCOB rotation with 2 years of cover crop showed the highest increase of TC content over the 20 year change period time; and (iv) interestingly, the no-till continuous corn (CCCC) rotation had higher TC than the soybean–soybean–corn–corn (SSCC) and corn–corn–soybean–winter wheat (CCSW). We concluded that conservation tillage (i.e., no-till) and incorporation of a cover crop into crop rotations had a positive effect in the accumulation of TC topsoil concentrations and could be suitable management practices to promote soil fertility and sustainability in our agricultural soils.


2020 ◽  
Author(s):  
Kurt-Christian Kersebaum ◽  
Susanne Schulz ◽  
Evelyn Wallor

<p>Climate change impact on crop production depends on the cultivated crop and its position within crop rotations and on site conditions, e.g. soils and hydrology, buffering adverse weather situations. We present a regional study across the federal state of Brandenburg/Germany based on gridded climate data and a digital soil map using the HERMES-to-Go model. The aim was to investigate defined crop rotations and common agricultural practices under current and future climate conditions regarding productivity and environmental effects. Two contrasting GCMs (HAD and MPI) were used to generate climate input for modelling for the RCPs 2.6 and 8.5.</p><p>5 different types of crop production were simulated by defining crop rotations over 4-5 years for soil quality rating groups. While one rotation is comprised by the most common crops, another rotation modifies the first one by introducing a legume followed by a more demanding crop. The third rotation intends to produce higher value crops, e.g. potatoes than the first one, while the fourth rotation has its focus on fodder grass and cereal production. Building on this the fifth rotation replaces the fodder grass by alfalfa. All rotations are simulated in shifted phases to ensure that each crop is simulated for each year.</p><p>Sowing, harvest and nitrogen fertilization were derived by algorithms based on soil and climate information to allow self-adaptation to changing climate conditions. The crop rotations are simulated under rainfed and irrigated conditions and with and without the implementation of cover crops to prevent winter fallow.</p><p>We used the digital soil map 1:300.000 for Brandenburg with 99 soil map units. Within the soil map unit, up to three dominant soil types were considered to achieve at least 65% coverage. 276 soil types are defined by their soil profiles including soil organic matter content and texture down to 2 meters. Groundwater levels are estimated using the depth of reduction horizons as constant values over the year, to consider capillary rise depending on soil texture and distance between the root zone and the groundwater table.</p><p>In total each climate scenario contains about 148.000 simulations of 30 years. Beside crop yields we analyse the outputs for trends in soil organic matter, groundwater recharge, nitrogen leaching and the effect on water and nitrogen management using algorithms for automatic management.</p><p>Results indicate that spring crops were more negatively affected by climate change than winter crops especially on soils with low water holding capacity. However, few areas with more loamy soils and potential contribution of capillary rise from a shallow groundwater even benefited from climate change. Irrigation in most cases improved crop yield especially for spring crops. However, further analysis is required to assess if irrigation gains an economic benefit for all crop rotations. Nitrogen leaching can be reduced by implementing winter cover crops. Soil organic matter is assessed to decline for most sites and rotations. Only the rotations with multiyear grass or alfalfa can keep the level, but not on all sites.</p>


2020 ◽  
Author(s):  
Andrew Nicholas Kadykalo ◽  
Kris Johnson ◽  
Scott McFatridge ◽  
C. Scott Findlay

Although agricultural “best (or beneficial) management practices” (BMPs) first emerged to mitigate agro-environmental resource challenges, they may also enhance ‘non-provisioning’ ecosystem services. The enthusiasm for adopting BMPs partially depends on evidence that doing so will lead to agro-environmental benefits while not substantially reducing crop productivity or farmer income. We survey and synthesize evidence in the existing literature to document the joint effects on agricultural crop yield and 12 ecosystem service (ES) associated with implementation of 5 agricultural BMPs (crop rotations, cover crops, nutrient management, perennial vegetated buffers, reduced or no tillage). We also analyze the prevalence of co-benefits (‘win-win’), tradeoffs, and co-costs (‘lose-lose’) outcomes. On the basis of a set of contextual variables we then develop empirical models that predict the likelihood of co-benefits relative to tradeoffs, and co-costs. We found thirty-six studies investigating 141 combinations of crop yields and non-provisioning ES outcomes (YESs) in the relevant literatures covering the period 1983-2016. The scope of the review is global, but included studies are geographically concentrated in the U.S. Corn Belt (Midwestern United States). In the literature sample, reporting of co-benefits (26%) was much more prevalent than reporting of co-costs (4%) between yields and ES. Tradeoffs most often resulted in a reduction in crop yields and an increase in ES (28%); this was marginally greater than studies reporting a neutral influence on crop yields and an increase in ES (26%). Other Y/ES combinations were uncommon. Mixed-effects models indicated reduced tillage and crop rotations had generally positive associations with YESs. Temporal scale was an informative predictor suggesting studies with longer time scales resulted in greater positive outcomes on YESs, on average. Our results are a step towards identifying those contexts where co-benefits or partial improvement outcomes of BMPs are more likely to be realized, as well as the impact of particular practices on specific ES.


2016 ◽  
Vol 14 (2) ◽  
pp. e0304 ◽  
Author(s):  
Diego N. Chavarría ◽  
Romina A. Verdenelli ◽  
Emiliano J. Muñoz ◽  
Cinthia Conforto ◽  
Silvina B. Restovich ◽  
...  

Agricultural systems where monoculture prevails are characterized by fertility losses and reduced contribution to ecosystem services. Including cover crops (CC) as part of an agricultural system is a promising choice in sustainable intensification of those demanding systems. We evaluated soil microbial functionality in cash crops in response to the inclusion of CC by analyzing soil microbial functions at two different periods of the agricultural year (cash crop harvest and CC desiccation) during 2013 and 2014. Three plant species were used as CC: oat (Avena sativa L.), vetch (Vicia sativa L.) and radish (Raphanus sativus L.) which were sown in two different mixtures of species: oat and radish mix (CC1) and oat, radish and vetch mix (CC2), with soybean monoculture and soybean/corn being the cash crops. The study of community level physiological profiles showed statistical differences in respiration of specific C sources indicating an improvement of catabolic diversity in CC treatments. Soil enzyme activities were also increased with the inclusion of CC mixtures, with values of dehydrogenase activity and fluorescein diacetate hydrolysis up to 38.1% and 35.3% higher than those of the control treatment, respectively. This research evidenced that CC inclusion promotes soil biological quality through a contribution of soil organic carbon, improving the sustainability of agrosystems. The use of a CC mixture of three plant species including the legume vetch increased soil biological processes and catabolic diversity, with no adverse effects on cash crop grain yield.


2015 ◽  
Vol 13 (3) ◽  
pp. e03SC01 ◽  
Author(s):  
José Guerrero-Casado ◽  
Antonio J. Carpio ◽  
Laura M. Prada ◽  
Francisco S. Tortosa

<p>Cover crops are an effective means to reduce soil erosion and to provide food and shelter for wildlife. However, in areas of intensive farming, which are characterised by the scarcity of weed communities, wild herbivores may focus their grazing on cover crops, which could make their implementation difficult. In this work, we test whether rabbit grazing can prevent the growth of herbaceous cover crops in olive groves in Southern Spain in addition to assessing the role of rabbit abundance and diversity of weeds in the development of cover crops. This question has been addressed by sowing <em>Bromus rubens</em> between the rows of five olive groves in Cordoba province (Spain). We then monitored the surface covered by <em>B. rubens,</em> along with both diversity of weed communities and rabbit abundance. Two rabbit exclusion areas were also placed in each olive grove in order to assess the impact of rabbits on the development of cover crops. Our results showed that the surface occupied by <em>B. rubens</em> was considerably higher in the rabbit exclusion areas (mean 56.8 ± 5.65 %) than in those areas in which they could feed (mean 35.6 ± 4.32 %). The coverage occupied by cover crops was higher in areas with lower rabbit density, although this relationship was modulated by the weed diversity index, since in areas with the same rabbit abundance the coverage was higher in those with a richer weed community. These findings suggest that high rabbit abundances can prevent the development of herbaceous cover crops in olive groves, particularly in areas in which alternative food resources (measured as weed diversity) are scarce.</p>


Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 445
Author(s):  
Laura Depalo ◽  
Giovanni Burgio ◽  
Serena Magagnoli ◽  
Daniele Sommaggio ◽  
Francesco Montemurro ◽  
...  

A key aspect in cover crop management is termination before the cash crop is planted. The aim of this study was to assess the effects of termination methods on ground-dwelling arthropods. The conventional mechanical termination method—i.e., green manuring by means of a disc harrow—was compared to flattening using a roller crimper. Two different crop systems were investigated for two growing seasons; cauliflower was grown in autumn after the termination of a mixture of cowpea, pearl millet, and radish, and tomato was cropped in spring and summer after the termination of a mixture of barley and vetch. Ground beetles (Coleoptera: Carabidae), rove beetles (Coleoptera: Staphylinidae), and spiders (Araneae) were sampled by means of standard pitfall traps throughout the growing season of both cash crops. The roller crimper increased the overall abundance of ground beetles in the first growing season of both cash crops, whereas in the second year, no significant effect could be detected. Rove beetles were more abundant in plots where the cover crops were terminated by the roller crimper. Finally, green manuring increased the abundance of spiders, especially on the first sampling date after cover crop termination. Albeit different taxa showed different responses, the termination of cover crops by a roller crimper generally increased the abundance of ground dwelling arthropods. Given that most of the sampled species were generalist predators, their increased abundance could possibly improve biological control.


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