Organic Crop Production Systems Research Articles

Encapsulation of Plant Biocontrol Bacteria with Alginate as a Main Polymer Material.

One of the most favored trends in modern agriculture is biological control. However, many reports show that survival of biocontrol bacteria is poor in host plants. Providing biocontrol agents with protection by encapsulation within external coatings has therefore become a popular idea. Various techniques, including extrusion, spray drying, and emulsion, have been introduced for encapsulation of biocontrol bacteria. One commonly used biopolymer for this type of microencapsulation is alginate, a biopolymer extracted from seaweed. Recent progress has resulted in the production of alginate-based microcapsules that meet key bacterial encapsulation requirements, including biocompatibility, biodegradability, and support of long-term survival and function. However, more studies are needed regarding the effect of encapsulation on protective bacteria and their targeted release in organic crop production systems. Most importantly, the efficacy of alginate use for the encapsulation of biocontrol bacteria in pest and disease management requires further verification. Achieving a new formulation based on biodegradable polymers can have significant effects on increasing the quantity and quality of agricultural products.

Who buys crop insurance? Predictors of the participation gap between organic and conventional farms

AbstractThis study examines the participation gap in crop insurance between organic and conventional producers. To solicit input from producers of organic and diversified crop production systems, we developed a national survey through the Organic Agriculture Research and Education Initiative (OREI) that resulted in over 1,000 valid responses, as well as data from the Agricultural Resource Management Survey (ARMS). Results suggest a high degree of correlation between crop insurance participation with respect to the degree of commercialization of a farm. Additionally, small and diversified operations report that the complexity and record keeping associated with crop insurance is often not worthwhile. This paper concludes with a discussion regarding future risk management education programs and how they can be better targeted by combining the use of crop insurance in conjunction with improved record keeping and a better understanding of loan requirements and documentation.

Soil microbial communities in tilled organic and no-till conventional crop production systems

Soil microbial communities in tilled organic and no-till conventional crop production systems

Economic analysis of organic cropping systems under different tillage intensities and crop rotations

AbstractCosts of production and organic price premiums are defining factors influencing the economic viability of organic crop production systems. Different agronomic practices, such as crop rotation and tillage intensity, are known to affect the economic performance of the production systems. The aim of this study was to compare the impact of two crop rotation sequences (simplified and diversified) and two levels of tillage intensity (high and low) on the cost of production, gross return and gross margin of crops when grown under organic management in the semi-arid Brown soil zone of the Canadian Prairies. The 2-year simplified rotation sequence consisted of forage pea (Pisum sativum L.) grown as a green manure followed by hard red spring wheat (HRSW) (Triticum aestivum L.), while the 4-year diversified rotation sequence was forage pea green manure followed by flax (Linum usitatissimum L.) or yellow mustard (Sinapis alba L.), field pea or lentil (Lens culinaris L.) and HRSW. Our hypothesis that a more diversified crop rotation would increase profitability over a traditional simplified crop rotation was supported by the findings. However, the findings did not support our hypothesis that reducing tillage intensity, and the combination of tillage reduction and diversified crop rotation through a synergetic response, would further enhance profitability. Analysis of the breakeven prices and breakeven yields for crops indicated the importance of adopting diversified crop rotations and choosing crops with high organic price premiums as means to maximize the long-term profitability of organic cropping systems.

Nitrogen-use efficiency of organic and conventional arable and dairy farming systems in Germany

Optimising nitrogen (N) management improves soil fertility and reduces negative environmental impacts. Mineral N fertilizers are of key importance in intensive conventional farming (CF). In contrast, organic farming (OF) is highly dependent on closed nutrient cycles, biological N fixation and crop rotations. However, both systems need to minimise N balances and maximise nitrogen-use efficiency (NUE). NUE of organic and conventional crop production systems was evaluated in three regions in Germany by analysing N input, N output and N balance of 30 pairs of one OF and one CF farm each from the network of pilot farms for the period 2009–2011; indicators were calculated using the farm management system REPRO. CF had higher N input in all farm pairs. In 90% of the comparisons, N output of CF was higher than OF, in 7% it was the same and in 3% lower. NUE was higher in 60% of the OF, the same in 37% and lower in only 3%. The NUE of crop production in OF was 91% (arable farms: 83%; mixed/dairy farms: 95%) and the NUE in CF was 79% (arable farms: 77%; dairy farms: 80%). N balance was lower in 90% of the OF. The yearly average N balance was four times higher in CF (59 kg N ha−1 a−1) than in OF (15 kg N ha−1 a−1). The results show a huge individual variability within OF and CF. Organic mixed/dairy farms had the lowest N balances and the highest NUE. A further expansion of OF area can help to reduce high N balances and increase the NUE of crop production.

On-farm land management strategies and production challenges in United States organic agricultural systems

The need to reduce the negative impacts of agriculture on the environment and the consumer demands for food produced without synthetic chemical inputs have led to organic agriculture production systems. The United States (US) commands about half of the market share of organic products worldwide and is home to half of the world's organic farmers, but limited information is available on trends of on-farm land-use practices and challenges in organic crop production systems. This study utilizes the agricultural production surveys from the United States Department of Agriculture (USDA) from 2008 to 2019 to investigate state and national trends in organic farm area, number, and sales, and to evaluate national trends in on-farm land-use practices and challenges facing US organic production. From 2008 to 2019, the number of certified organic farms, land area, and sales increased by 5, 6, and 12%, respectively. The use of green and animal manures is the most common land-use practice in certified organic crop production systems. The number of farms using the on-farm organic practices remained the same or increased steadly except organic mulch/compost which declined. However, all the practices declined proportionally, except rotational grazing which recorded an increase in 2019. The most significant primary challenges faced by certified organic farmers are related to regulations of organic practices and production costs which worsen over time. United States certified organic production has the potential for expansion in terms of farm numbers, land area, markets, and increased adoption of regenerative agricultural practices. However, for this to occur, efforts involving farm-level research and policy reviews with direct farmer involvement are needed to address these primary challenges facing organic farmers.

Conventional, integrated and organic field crop production systems

Agriculture is usually developed as much and just society where there is a branch of the economy. Today, there are different directions from industry agriculture to many concepts based on ecological principles. Future of agriculture development in the XXI century will imply sustainable agriculture as the alternative to the industrial agriculture. One of the goals of the sustainable agriculture movement is to create farming systems that mitigate or eliminate environmental harms associated with industrial agriculture. That aim can be realized only in flexible cultural practices in real agroecological conditions (different regional characteristics, soil types, adapted cultivars for low-input or organic production). Based on these facts, we must have the right answers in order to mitigate if not to completely eliminate these effects. Agronomic aspect of looking into the problem requires a good knowledge of our crop needs for primary vegetative factors as well as temperature and moisture in conventional agricultural production but and in organic production also too. Agricultural intensification could help alleviate destructive pressure on habitats by meeting agricultural production needs on existing farmland. Those modifications of all cultural practices as well as adequate assortment are necessary for organic crop production. A need for healthier environment and numerous negativities caused by present conventional agriculture have led to the trends of the future development of agriculture based on the complete absence of chemistry, among which is the so-called organic agriculture. Organic production represents the holistic production management system of agricultural, food and other products, which combines a good agricultural practice, high degree of biological diversity (biodiversity), conservation of natural resources, application of high standards of animal welfare and production mode in accordance with the preferences of certain consumers for the products whose production uses natural substances. Today, technological progress in communication, along with the information revolution made possible the revival of such a concept, as well as its applicability on a larger scale. Precision agricultural technologies, such as Global Positioning Systems (GPS), Geographic Information Systems (GIS), remote sensing, yield monitors, and guidance systems for variable rate application, made it possible to manage within-field variation on large scales. The essence of this technology is based upon the availability of data and the use of this data in the decisionmaking process, as well the data integrating influence of different factors on yield and quality parameters. Organic agriculture is one of the most interesting current trends in agriculture completely based on strong ecological principles and the absence of application of agrochemicals (pesticides, fertilizers, hormones), GMO, etc. Organic agriculture is a holistic way of farming: besides production of goods of high quality (better flavour, high content dry matter, vitamins, antioxidants); conservation of the natural resources (soil, water) and richness of biodiversity. Organic farming systems have their important application in field crop production with an extraordinary nutritive and protective role. Important changes will appear in application some cultural practices: soil tillage, crop rotation, fertilization and plant protection. We can expect changes in soil tillage with significant level of reduction; dominate by conservation tillage because of positive influence on soil and saving energy.

How Effective Is Conservation Biological Control in Regulating Insect Pest Populations in Organic Crop Production Systems?

Simple SummaryOrganic crop production systems typically rely on conservation biological control to increase and sustain natural enemies including parasitoids and predators that will regulate insect pest populations below damaging levels. The use of flowering plants or floral resources to attract and retain natural enemies in organic crop production systems has not been consistent, based on the scientific literature, and most importantly, many studies do not correlate an increase in natural enemies with a reduction in plant damage. This may be associated with the effects of intraguild predation or the negative effects that can occur when multiple natural enemies are present in an ecosystem. Consequently, although incorporating flowering plants into organic crop production systems may increase the natural enemy assemblages, more robust scientific studies are warranted to determine the actual effects of natural enemies in reducing plant damage associated with insect pest populations.Organic crop production systems are designed to enhance or preserve the presence of natural enemies, including parasitoids and predators, by means of conservation biological control, which involves providing environments and habitats that sustain natural enemy assemblages. Conservation biological control can be accomplished by providing flowering plants (floral resources) that will attract and retain natural enemies. Natural enemies, in turn, will regulate existing insect pest populations to levels that minimize plant damage. However, evidence is not consistent, based on the scientific literature, that providing natural enemies with flowering plants will result in an abundance of natural enemies sufficient to regulate insect pest populations below economically damaging levels. The reason that conservation biological control has not been found to sufficiently regulate insect pest populations in organic crop production systems across the scientific literature is associated with complex interactions related to intraguild predation, the emission of plant volatiles, weed diversity, and climate and ecosystem resources across locations where studies have been conducted.

Comparison of the Effects of Different Crop Production Systems on Soil Physico-Chemical Properties and Microbial Activity under Winter Wheat

In many areas, organic crop production systems have been shown to contribute to maintaining good soil condition. The organic production system has been recommended as an alternative to conventional agriculture. However, in order to recommend this practice in new regions, it is necessary to obtain information about its effects and consequences in local environmental conditions. The research was completed during 2016–2018 in Osiny (Lublin region, Poland) on a field experiment established 26 years previously in a Haplic Luvisol soil. The research was aimed at comparing the effects of long-term use of tilled soil with organic (ORG) and conventional (CON) crop production systems with those in non-tilled soil under permanent grass (PRG) as a control. This comparison was done on the basis of changes in the values of soil properties as follows: Total porosity (TP), total organic matter (OM), particulate organic matter (POM), humic substances (HS), water-extractable carbon (WEC), microbial biomass carbon pool (MBC) and dehydrogenase activity (DH). Soil samples were collected from experimental fields (each treatment 1 ha) under winter wheat and permanent grass each year from 0–5, 5–10, 15–20 and 30–35 cm depths. Over the three year study period, it was found that permanent grass and the organic crop production system contributed to increased soil OM, POM, HS, WEC and MBC contents and DH activity compared to the CON system, especially in the top soil layer, 0–5 cm. To obtain a clearer picture of soil quality change our study examined for the first time the metabolic potential index (MPI) as a ratio of dehydrogenase activity to the soluble organic carbon content. The MPI values confirmed the increase of metabolism in ORG soil as a consequence of management practices compared with CON soil. The obtained correlations showed strong mutual relationships within properties of the heterogeneous soil complex. The results show the positive effects of the ORG management system causing soil condition improvement which is based on organic fertilization, enriching the soil with a large amount of plant residues in creating positive changes in the soil quality in contrast to the CON system.

Impact of Years in Bahiagrass and Cultivation Techniques in Organic Vegetable Production on Epigeal Arthropod Populations

Plantings of perennial grasses have been shown to be an effective means to enhance soil qualities for organic production. Similarly, tillage methods can significantly impact production in organic crop production systems. We have previously examined direct effects of these practices on crop yields, profitability, and soil quality for rotations of organic vegetables in a 4-yr study in northern Florida, but less is known about the effects of these treatments on arthropods. We report here on experiments that used large fields of Argentine bahiagrass, Paspalum notatum Flugge (Poaceae) ‘Tifton 9,’ converted to seasonal vegetable rotations of oat/rye, bush beans, soybeans, and broccoli in a nested design using 4 levels (yr) of continuous bahiagrass production prior to vegetable rotations and 2 tillage methods (conventional and strip tillage). During the fourth yr of the study, we conducted pitfall trapping on a subset of plots involving all 8 treatments (4 bahiagrass treatments and 2 tillage treatments) to examine effects on epigeal arthropods. Over 10,000 organisms and 48 species were identified with 36 arthropod species comprising greater than 97% of the collected specimens. Fields with increasing yr in bahiagrass significantly increased the number of carabid beetles, whereas there was a decline in total herbivores. Tillage treatments impacted arthropod abundance with a noted decline in total carabids collected in strip tilled plots. Pest management implications of these treatments are discussed.

In vitro compatibility of Beauveria bassiana strain ATCC 74040 with copper fungicides

AbstractCopper fungicides and mycoinsecticides based on entomopathogenic fungi Beauveria spp. are the most common pesticides used in organic crop production systems. The in vitro effects of the copper fungicides copper oxide, copper hydroxide, copper oxychloride, copper sulphate, dicopper chloride trihydroxide and tribasic copper sulphate were investigated for mycelial growth, sporulation and conidial germination of the ATCC 74040 commercial strain of Beauveria bassiana. Mycelial growth was evaluated on potato dextrose agar plates with 100%, 75%, 50%, 25%, 12.5%, 6.25% and 0% of the recommended application rates of each fungicide at 15 and 25°C. Sporulation and conidial germination were determined at the recommended field doses of each fungicide at 25°C. All copper fungicides had fungistatic or fungicidal effects on B. bassiana that varied according to the dose. Only in two cases, copper oxide at 15°C and copper hydroxide at 25°C, at the lowest concentration of 6.5%, was mycelial growth not statistically significantly inhibited. Inhibition of mycelial growth depended both on the fungicide and its concentration, and partly on temperature. Both sporulation and conidial germination of B. bassiana were significantly inhibited by all fungicides. All fungicides inhibited the sporulation in a similar way (99.8%–100%). With the exception of copper oxychloride (inhibition, 13.6%), the other fungicides showed high detrimental effects on conidial germination (inhibition, 91.7%–100%). The fungus was strongly affected by some fungicides even at the lowest doses. The biological index used for the B. bassiana with copper fungicides ranged from 0.6 (copper sulphate) to 18.1 (copper oxychloride). Therefore, the tested fungicides were classified into the upper half of the highly toxic (T) category and are considered incompatible with the entomopathogenic fungus B. bassiana strain ATCC 74040 under in vivo experimental conditions. These results need to be further verified in vitro under both greenhouse and open‐field conditions.

Occurrence of common scab and black scurf in selected potato cultivars grown under organic and conventional crop production systems

Occurrence of common scab and black scurf in selected potato cultivars grown under organic and conventional crop production systems

Exploiting Olive Mill Byproducts and Other Waste for Organic Weed Management

Weed management represents one of the most serious and costly challenges in organic crop production systems. Agricultural waste/byproducts might present phytotoxicity that can be exploited to control weeds. Two experiments were designed to study the effects of four concentrations of olive vegetation water (OVW) and a control water treatment (with no OVW) on cheeseweed (Malva parviflora L.) seed germination in petri dishes and pots. In a third experiment, two rates of four composts (crop residue mix (CR), olive pomace (OP), dairy/horse manure (DM), and an OP/DM mix) were mixed into a clay‒loam soil at 0.10 or 0.20 L L−1, to assess their effects on weed number and biomass, in addition to bell pepper (Capsicum annuum L.) growth. In the petri dish experiment, the three highest OVW concentrations completely prohibited germination during the five-week duration of the study. For the pot experiment, 25 mL application of OVW significantly delayed and reduced cheeseweed germination, with the reduction being proportional to the concentration of OVW. In the third experiment, composts reduced weed dry matter (composed mostly of purslane (Portulaca oleracea L.)), with the CR compost being the most effective, reducing total weed biomass by 67% compared to the control. CR10 and DM10 tended to increase bell pepper yields, although none of the plant parameters was significantly affected by the compost treatments.

Effects of crop production practices on soil characteristics and metabolic diversity of microbial communities under winter wheat

The aim of this research was to compare the effects of organic (ORG, no mineral fertilisers and pesticides) and conventional (CON, with mineral fertilisation and plant protection chemicals) crop production systems on some soil properties: soil organic matter (SOM) and particulate organic matter (POM) contents, dehydrogenase activity and metabolic microbial diversity (Biolog EcoPlate™). Samples of Haplic Luvisol soil were collected from 23-year-old experimental fields under winter wheat from the depth layers of 0–5, 5–10, 15–20 and 30–35cm. Soil under ORG showed higher contents of SOM, POM and POM expressed as a percentage of SOM by 16.0%, 25.6% and 23.9% respectively, in particular down to 5cm depth, compared with the CON system. Also, dehydrogenase activity was 47.5% higher under the ORG than the CON system. The Biolog EcoPlate revealed higher metabolic microbial diversity in soil under ORG crop production system compared with CON. This result was supported by the average well colour development and Shannon’s diversity index values. Significant correlations between soil quality parameters and winter wheat yield confirmed their effectiveness as indicators of soil disturbance. The results showed that the ORG system much better maintained SOM and soil fertility compared with CON.

Valuation of ecosystem services in organic cereal crop production systems with different management practices in relation to organic matter input

As the degradation of global ecosystem services (ES) continues in the last five decades, maintaining or even enhancing the ES of agro-ecosystem is one of the approaches to mitigate the global ES loss. This study provides the first estimate of an economic valuation of ES provided by organic cereal crop production systems with different management practices in relation to organic matter input (low, medium and high). Our results show that organic matter inputs significantly affect the total ES value on organic cereal crop production systems. The system with high organic matter input has the highest gross total ES value (US$ 1969ha−1yr−1), followed by the low organic matter input system (US$ 1688ha−1yr−1), and the lowest ES value are found in the medium organic matter input system (US$ 1492ha−1yr−1). Organic matter inputs have strong positive relationship with non-marketable ES values, while this relationship was not found in marketable ES values. Monetizing the ES can be used by land managers and policy makers to adjust management practices in terms of organic matter input in cereal production system with a long term goal for sustainable agriculture.

Flame weeding as an alternative tool for weed management in agronomic crops: Revisiting the old concept

Flaming as a vegetation control method is dating back to mid-1800s. This type of weeding is based on the concept of utilizing heat as a source for vegetation control. Various levels of heat can either damage plant tissue or kill a plant. The critical temperature for leaf mortal­ity ranges from 55°C to 70°C. The mechanism by which heat injury affects the plant varies from species to species and is complex. In general, plants die from the loss of membrane semi-permeability and cuticle breakdown (resulting in plant desiccation), denaturation of proteins, water boiling, and other chemical decomposition. The general principle behind flaming is to cause plant death by raising temperatures high enough to boil water inside the plant tissue, which further expends helping disintegrate the plants' cellular membranes. Flaming has a potential to be used effectively in organic crop production systems in at least 6 agronomic crops (field maize, sweet maize, popcorn, sorghum, soybean, sunflower) when conducted properly at the most tolerant growth stage. It is important to mention that propane flaming should not be the only method for non-chemical weed control; however, it could be part of an integrated weed management program. Other measures are still needed to control weeds that emerge throughout the growing season.

An Undergraduate Student Project to Improve Mechanical Control of Perennial Nutsedges with a Peanut Digger in Organic Crop Production

Yellow and purple nutsedge are common in the southeastern United States, and both perennial species are difficult to control in organic crop-production systems. Tubers are generally confined to the upper portions of the soil profile and are vulnerable to desiccation when brought to the soil surface. A peanut digger is a common implement found in the coastal plain region of the southeastern United States and has shown promise controlling perennial nutsedges in fallow sites. The peanut digger undercuts perennial nutsedges, deposits weeds on the soil surface, and exposes weeds to desiccation. However, rainfall after tillage with the peanut digger allows displaced nutsedges to survive. As part of a senior-level class project, undergraduate mechanical engineering students from Auburn University designed and constructed a cart attached to a peanut digger that collected nutsedges. Key features included a custom hitch that allowed the correct plane of movement and a hydraulic conveyor system that discarded the perennial nutsedges off-site, away from the field. The prototype was tested in a fallow location in the summer of 2014 with a yellow nutsedge infestation averaging 148 plants m−2. One week after the initial field test, tillage using the peanut digger with specialized cart reduced yellow nutsedge densities in the tilled area by > 99%.

Soil microbial substrate properties and microbial community responses under irrigated organic and reduced-tillage crop and forage production systems.

Changes in soil microbiotic properties such as microbial biomass and community structure in response to alternative management systems are driven by microbial substrate quality and substrate utilization. We evaluated irrigated crop and forage production in two separate four-year experiments for differences in microbial substrate quality, microbial biomass and community structure, and microbial substrate utilization under conventional, organic, and reduced-tillage management systems. The six different management systems were imposed on fields previously under long-term, intensively tilled maize production. Soils under crop and forage production responded to conversion from monocropping to crop rotation, as well as to the three different management systems, but in different ways. Under crop production, four years of organic management resulted in the highest soil organic C (SOC) and microbial biomass concentrations, while under forage production, reduced-tillage management most effectively increased SOC and microbial biomass. There were significant increases in relative abundance of bacteria, fungi, and protozoa, with two- to 36-fold increases in biomarker phospholipid fatty acids (PLFAs). Under crop production, dissolved organic C (DOC) content was higher under organic management than under reduced-tillage and conventional management. Perennial legume crops and organic soil amendments in the organic crop rotation system apparently favored greater soil microbial substrate availability, as well as more microbial biomass compared with other management systems that had fewer legume crops in rotation and synthetic fertilizer applications. Among the forage production management systems with equivalent crop rotations, reduced-tillage management had higher microbial substrate availability and greater microbial biomass than other management systems. Combined crop rotation, tillage management, soil amendments, and legume crops in rotations considerably influenced soil microbiotic properties. More research will expand our understanding of combined effects of these alternatives on feedbacks between soil microbiotic properties and SOC accrual.

Approaches to disease management in organic crop production systems: a case of cassava mosaic disease and black pod disease of cocoa

Organic agriculture in Africa has grown in the past years, to a point where it has become visible and measurable. However, West Africa lags behind other African regions in organic agriculture. Effective management of plant diseases is very important for profitable organic crop production. Economic losses incurred from the devastation of cocoa by the black pod disease of cocoa from different producing regions worldwide are quite enormous and crop losses estimated at 44% have been reported. Similarly, cassava mosaic disease epidemics are frequent in subsistence agriculture with crop losses throughout sub-Saharan Africa between 19 and 27 metric tonnes and an estimated economic loss of over US$1.5 billion per year. We review available options for management of black pod disease of cocoa, on an economic security crop, and cassava mosaic disease affecting cassava, a food security crop under organic production system. Additionally, we further encourage organic production of cocoa and cassava in West Africa, and recommend an integrated pest and disease management approach which will involve a systematic combination of the management methods that are feasible for smallholder farmers to practice. Future research needs are also identified.

Companion Crops for Organic Alfalfa Establishment

In organic cropping systems, companion crops are used for establishment of forage legumes, but a comparison of alternative companion crops for alfalfa (Medicago sativa L.) has not been conducted. We determined the yield of spring‐seeded companion crops and their effect on alfalfa forage yield, weed yield, and net return in five environments. Crops were managed using organic practices. Barley (Hordeum vulgare L.) was among the highest yielding small grains, while annual ryegrass (Lolium multiflorium Lam.) was among the highest yielding forage companion crops. Companion crop effects on alfalfa yields were inconsistent among environments. In the establishment year, in two environments, alfalfa yields were similar for all establishment treatments. In three environments, rapid cycling brassica (Brassica rapa L.), annual ryegrass, and winter wheat (Triticum aestivum L.) companion crop treatments often resulted in alfalfa yields that were greater than those following field pea (Pisum sativum L.), flax (Linum usitatissimum L.), barley, oat (Avena sativa L.), and wheat. In the year following seeding, alfalfa yields in three environments were similar for all treatments, while in two environments, all treatments except field pea had yields equal to a weedy control. Spring‐seeded wheat, barley, and oat companion crops provided greater net returns than the control, field pea, flax, or forage (non‐vernalized winter wheat, annual ryegrass, and rapid‐cycling brassica) companion crop treatments. Small grain companion crops provide high and consistent net returns without adversely affecting alfalfa yields, and should be used for alfalfa establishment in organic crop production systems.