High-input Conventional System Research Articles

Soil quality and phosphorus status after nine years of organic and conventional farming at two input levels in the Central Highlands of Kenya

Under temperate climate conditions, organic farming systems show improved soil quality compared to non-organic systems, whereas little long-term research on the impact of organic farming on soil quality has been conducted in sub-Saharan Africa. Within the system comparison (SysCom) project, two long-term field experiments were set up in 2007 in the sub-humid Central Highlands of Kenya to compare organic and conventional farming at two input levels (high input systems with recommended rates of nitrogen (N), phosphorus (P) and pesticides and with irrigation vs. rain-fed low input systems with low N, P and pesticides), with a similar design at both sites. The two sites differ mainly in their inherent soil properties and in the amount and distribution of rainfall. At the end of each three-year crop rotation period, we analyzed a set of chemical, biological and physical soil quality parameters in 0–20 cm soil depth. After nine years, microbial parameters seemed to have reached a steady state, whereas chemical parameters were still changing. Most soil quality parameters were highest under the high input organic farming system. The high input conventional system performed well in preserving several soil quality indicators, but a trend for acidification and the lack of soil carbon build-up raise concerns about the long-term sustainability of the system. Low input organic and conventional farming systems did not improve soil quality and even showed decreasing trends in several chemical parameters. Total and available P accumulated over time, especially in both high input systems, suggesting increasing risks of losses to the environment. Pronounced site effects revealed strong interactions with pedo-climatic conditions, with soil quality under high input organic farming improving to a greater extent at the site with more favorable conditions. Besides effects on soil quality, important criteria for sustainable input levels are thus the general availability of inputs, resulting nutrient input–output budgets as well as interactions of inputs with inherent soil properties.

Understanding the Long-Term Weed Community Dynamics in Organic and Conventional Crop Rotations Using the Principal Response Curve Method

AbstractWeeds have acquired evolutionary adaptations to the diverse crop and weed management strategies used in cropping systems. Therefore, changes in crop production practices such as conventional to organic systems, tillage-based to no-till systems, and diversity in crop rotations can result in differences in weed community composition that have management implications. A study was carried out to understand the weed community dynamics in a long-term alternative cropping systems study at Scott, SK, Canada. Long-term (18-yr) weed community composition data in wheat (Triticum aestivumL.) in ORG (organic), RED (reduced-input, no-till), and HIGH (high-input, conventional tillage) systems with three levels of crop rotation diversity, LOW (low diversity), DAG (diversified annual grains), and DAP (diversified annuals and perennials), were used to study the effect of different cropping systems and the effect of environment (random temporal effects) on residual weed community composition using the principal response curve (PRC) technique. The interaction between cropping systems and year-to-year random environmental changes was found to be the predominant factor causing fluctuations in weed community composition. Furthermore, the single most predominant factor influencing the weed composition was year-to-year random changes. Organic systems clearly differed from the two conventional systems in most years and had more diverse weed communities compared with the two conventional systems. The two conventional systems exhibited similar weed composition in most years. In this study, the use of the PRC method allowed capture of the real temporal dynamics reflected in the cropping systems by time interaction. This study further concludes that moving from a tillage-based, high-input conventional system to a no-till, reduced-input system did not cause significant changes in the weed community composition throughout the time period, but diversity in organic systems was high, probably due to increased occurrence of some difficult to control species.

Insect community composition and functional roles along a tropical agricultural production gradient

High intensity agricultural production systems are problematic not only for human health and the surrounding environment, but can threaten the provision of ecosystem services on which farm productivity depends. This research investigates the effects of management practices in Costa Rica on on-farm insect diversity, using three different types of banana farm management systems: high-input conventional system, low-input conventional system, and organic system. Insect sampling was done using pitfall and yellow bowl traps, left for a 24-h period at two locations inside the banana farm, at the edge of the farm, and in adjacent forest. All 39,091 individual insects were classified to family level and then morphospecies. Insect species community composition and diversity were compared using multivariate statistics with ordination analysis and Monte Carlo permutation testing, and revealed that each of the management systems were significantly different from each other for both trap types. Insect diversity decreased as management intensity increased. Reduced insect diversity resulted in fewer functional groups and fewer insect families assuming different functions essential to ecosystem health. Organic farms had similar species composition on the farm compared to adjacent forest sites, whereas species composition increasingly differed between farm and forest sites as management intensity increased. We conclude that while organic production has minimal impact on insect biodiversity, even small reductions in management intensity can have a significantly positive impact on on-farm insect biodiversity and functional roles supported.

Physiological responses of processing tomato in organic and conventional Mediterranean cropping systems

Processing tomato is a globally important horticultural crop. It is generally grown in high-input conventional systems, and there is little knowledge regarding its physiological responses in organic cultivation. Therefore, the aim of this work was to determine the influence of organic management on the physiological behavior of cultivars of processing tomato usually cultivated in conventional management in a Mediterranean area. The study was performed by means of: (1) field testing of a set of commercial cultivars for 2 years, in two systems, in one location in Southern Italy, and (2) crop physiological investigations during the growth cycle of processing tomato. Results of the two-year trials indicate that, under the organic cropping system, processing tomato showed, as 2 years average, higher intercellular CO2 concentration (Ci) (+10.3%), transpiration (E) (+15.5%) and stomatal conductance (gs) (+16.5%). Average net assimilation (A) was similar in the two systems and differences were only observed depending on years. In contrast, average leaf area index (LAI) and water use efficiency (WUE) were lower in the organic cropping system (−42% and −17.8%), as were average fruit (FDW) and total (TDW) dry weight (−37.5% and −29%). In our conditions, LAI at the end of the cultivation was highly correlated with total and fruit dry weight. As differences in fruit and total dry weight of processing tomato cannot be explained by differences in net assimilation per leaf area unit, other reasons may be linked to the effects of the organic management on the crop as weeds and pathogens.

Effects of butter from mountain-pasture grazing cows on risk markers of the metabolic syndrome compared with conventional Danish butter: a randomized controlled study

BackgroundThere is considerable interest in dairy products from low-input systems, such as mountain-pasture grazing cows, because these products are believed to be healthier than products from high-input conventional systems. This may be due to a higher content of bioactive components, such as phytanic acid, a PPAR-agonist derived from chlorophyll. However, the effects of such products on human health have been poorly investigated.ObjectiveTo compare the effect of milk-fat from mountain-pasture grazing cows (G) and conventionally fed cows (C) on risk markers of the metabolic syndrome.DesignIn a double-blind, randomized, 12-week, parallel intervention study, 38 healthy subjects replaced part of their habitual dietary fat intake with 39 g fat from test butter made from milk from mountain-pasture grazing cows or from cows fed conventional winter fodder. Glucose-tolerance and circulating risk markers were analysed before and after the intervention.ResultsNo differences in blood lipids, lipoproteins, hsCRP, insulin, glucose or glucose-tolerance were observed. Interestingly, strong correlations between phytanic acid at baseline and total (P<0.0001) and LDL cholesterol (P=0.0001) were observed.ConclusionsLack of effects on blood lipids and inflammation indicates that dairy products from mountain-pasture grazing cows are not healthier than products from high-input conventional systems. Considering the strong correlation between LDL cholesterol and phytanic acid at baseline, it may be suggested that phytanic acid increases total and LDL cholesterol.Trial registrationClinicalTrials.gov, NCT01343589

Use of the Environmental Impact Quotient to Estimate Health and Environmental Impacts of Pesticide Usage in Peruvian and Ecuadorian Potato Production

Currently there is no effective mechanism for measuring the potential benefits of integrated pest and disease interven-tions in terms of reducing pesticide risks in potato production in developing countries. The environmental impact quotient (EIQ), a composite hazard indicator, was applied to data from potato field trials implemented in Ecuador to evaluate the practical boundaries of this metric related to potato production practices in the Andes. The EIQ was also applied to data from two independent farmer surveys, one from Peru and one from Ecuador to compare potato farming practices and the utility of the EIQ when applied to existing survey data. In the Ecuadorian field trials, the EIQ values, i.e., environmental impact (EI) per ha, varied greatly among the different potato systems tested and ranged from 40 for an integrated pest management system (resistant cultivar plus less hazardous pesticides) to 1235 for a high-input conventional system (susceptible cultivar plus frequent use of hazardous pesticides). Thus, this parameter demonstrates substantial variation under different conditions and different crop management approaches. EI per ha values from the two surveys fell within the range found in the field trial, but in the survey values were toward the lower end, ranging from 64 to 213. Methodical and biophysical factors are discussed that may account for the relatively low EI per ha found in the field survey data. Our study demonstrates the utility of the EIQ for assessing health and environmental hazards of potato production in the Andes and potentially other areas in the developing world. Nonetheless, there are limitations to the EIQ as presently used and care is needed in the interpretation of results. We see our work as an initial step in the development of an integrated metric to estimate environmental and human health hazards related to pesticide use in potato production in the diverse conditions of developing countries.