Organic farming

About: Organic farming is a research topic. Over the lifetime, 7254 publications have been published within this topic receiving 138030 citations. The topic is also known as: pertanian organik & organic farming.

Desert farming benefits from microbial potential in arid soils and promotes diversity and plant health

Abstract: Background To convert deserts into arable, green landscapes is a global vision, and desert farming is a strong growing area of agriculture world-wide. However, its effect on diversity of soil microbial communities, which are responsible for important ecosystem services like plant health, is still not known. Methodology/Principal Findings We studied the impact of long-term agriculture on desert soil in one of the most prominent examples for organic desert farming in Sekem (Egypt). Using a polyphasic methodological approach to analyse microbial communities in soil as well as associated with cultivated plants, drastic effects caused by 30 years of agriculture were detected. Analysing bacterial fingerprints, we found statistically significant differences between agricultural and native desert soil of about 60%. A pyrosequencing-based analysis of the 16S rRNA gene regions showed higher diversity in agricultural than in desert soil (Shannon diversity indices: 11.21/7.90), and displayed structural differences. The proportion of Firmicutes in field soil was significantly higher (37%) than in the desert (11%). Bacillus and Paenibacillus play the key role: they represented 96% of the antagonists towards phytopathogens, and identical 16S rRNA sequences in the amplicon library and for isolates were detected. The proportion of antagonistic strains was doubled in field in comparison to desert soil (21.6%/12.4%); disease-suppressive bacteria were especially enriched in plant roots. On the opposite, several extremophilic bacterial groups, e.g., Acidimicrobium, Rubellimicrobium and Deinococcus-Thermus, disappeared from soil after agricultural use. The N-fixing Herbaspirillum group only occurred in desert soil. Soil bacterial communities were strongly driven by the a-biotic factors water supply and pH. Conclusions/Significance After long-term farming, a drastic shift in the bacterial communities in desert soil was observed. Bacterial communities in agricultural soil showed a higher diversity and a better ecosystem function for plant health but a loss of extremophilic bacteria. Interestingly, we detected that indigenous desert microorganisms promoted plant health in desert agro-ecosystems.

Comparison of organic and conventional farms: challenging ecologists to make biodiversity functional

Abstract: With the rise of organic farming in the United States and worldwide, ecologists are being presented with new opportunities to link basic and applied ecology through research on biodiversity and ecosystem services. We present evidence from our own research and a review of the literature to assess the evidence for enhanced insect pest control as a consequence of greater biodiversity on organic farms. Despite the frequency of claims in the literature that biodiversity is beneficial, we found that few studies have measured biodiversity effects on pest control and yield on organic farms compared to conventional farms. Relevant studies in agricultural or natural settings suggest that an increase in the diversity of insect predators and parasitoids can have positive or negative effects on prey consumption rates. We therefore call for a stronger scientific basis for evaluating pest suppression effects due to enhanced natural enemy diversity. We suggest several avenues of research to assess the relationship between biodiversity and effective biological control, to obtain the information needed to manage natural enemy diversity, and to estimate the value-added component of on-farm biodiversity in terms of pest control services.

Pest damage and arthropod community structure in organic vs. conventional tomato production in California

Abstract: Summary 1. To test common assumptions that the reduction in agrochemicals on organic farms allows (i) the conservation of biodiversity but (ii) has some cost in terms of increased pest damage, we compared arthropod communities and pest damage levels to fresh market tomato Lycopersicon esculentum on 18 commercial farms. These farms represented a range of management practices, with half of them operating as certified organic production systems and half as conventional operations. 2. Purported drawbacks to the adoption of organic farming include an increased incid ence of pest damage and higher risk of pest outbreaks. Although insect pest damage levels varied across the spectrum of farm management practices, they were not asso ciated with whether the farming operation was organic or conventional; organic and conventional farms did not differ significantly for any type of damage to tomato foliage or fruit. 3. Although conventional and organic farms shared a similar range of arthropod damage levels to tomato, we detected a significant difference between the actual community structures of arthropods associated with the crop. Using canonical discriminant analysis, we found that whereas herbivore abundance did not differ, higher natural enemy abundance and greater species richness of all functional groups of arthropods (herbivores, predators, parasitoids and other) distinguished organic from conventional tomato. Thus, any particular pest species would have been associated with a greater variety of herbivore species (diluted) and subject, on average, to a wider variety and greater abundance of potential parasitoids and predators, if it occurred in organically grown tomato. 4. Trophically based community parameters, specifically species richness and relative abundance of functional guilds, were clearly associated with farm management category (organic vs. conventional). However, the abundance patterns of prominent pests and natural enemies were associated with specific on-farm practices or landscape features. Fallow management, surrounding habitat and transplant date of the crop field were strongly associated with arthropod species that explained the major variability among farms. Insecticide intensity was a weaker factor. Other factors, such as distance to riparian habitats and tissue nitrogen levels, did not emerge as indicators of pest or natural enemy abundance. 5. This comparative study of active commercial farms does not support predictions of increased crop loss in California tomato when synthetic insecticides are withdrawn. It highlights the importance of large-scale on-farm comparisons for testing hypotheses about the sustainability of agro-ecosystem management schemes and their effects on crop productivity and associated biodiversity.

Composted and Noncomposted Manure Application to Conventional and No-Tillage Systems: Corn Yield and Nitrogen Uptake

Abstract: Manure application to the soil surface may not be as effective as incorporated manure for crop production, because of potential N loss. An experiment was conducted to determine the effects of composted (compost) and noncomposted manure from beef cattle (Bos taurus) feedlots on corn (Zea mays L.) yield and N uptake under two tillage systems in 4 years. Conventional and no-till systems were used as main plots, and subplots consisted of application of composted and noncomposted manure and fertilizer to provide for corn N requirements, and check treatments. Manure and compost were applied and immediately incorporated by disking in the conventional system and left on the surface in the no-till. Fertilizer was incorporated in the conventional system and surface-applied in the no-till system each spring prior to planting. Results showed that in 3 out of 4 years there was no effect of tillage on corn grain yields of plots receiving manure or compost. Manure and compost application resulted in similar grain yield as that for fertilizer treatment in all years except for no-till in 1996. First-year N availability was approximately 38% for manure and 20% for compost in both tillage systems. Apparent N use efficiency was 17% for manure, 12% for compost, and 45% for the fertilizer treatment across 4 years. Chlorophyll meter readings, indicating relative plant N concentration at different stages of growth, were closely related to N uptake and grain yield in years with adequate water supply, but not in the drier year of 1995. Stalk NO 3 - -N concentration at harvest was above the critical level of 2000 mg kg -1 for the fertilizer treatment in 1995 but was low (<200 mg kg -1 ) for manure and compost treatments. Stalk NO 3 - -N concentration did not exceed the critical level for any treatment in other years. When the correct N availability factor is used, beef cattle feedlot manure and compost can be effectively utilized in no-till corn production systems.