Greenhouse gas emissions from conventional and organic cropping systems in Spain. II. Fruit tree orchards

Endophytic fungi dwell in the tissues of plants without causing disease symptoms. Coffee production can be performed using conventional or organic crop systems. Studies have been carried out to assess the endophytic fungal community in a conventional coffee crop system. However, little is known about them in organic conditions. Comparisons were made between an endophytic fungal community from leaves of Coffea arabica in organic and conventional crop systems. Mature and healthy leaves of C. arabica were collected from two crop systems during the wet and dry seasons, in the Northeast Brazil. A total of 432 fragments were analyzed and 336 specimens of endophytic fungi were isolated and distributed among 16 genera and 17 species. Colletotrichum gloeosporioides complex and Phyllosticta capitalensis were the most common fungi in conventional and organic crop systems, respectively. The largest number of fungal endophytes was observed during the wet season, although the diversity index and species richness were higher in the dry season. The endophytic fungal communities in conventional and organic crop systems exhibited 50.61% similarity, with six species occurring uniquely in organic and five in conventional coffee. Therefore, more research is needed to confirm that the species could be used as indicators of these management systems.

How the productivity of crops in organic arable farming may be sustainably increased remains a key issue. We combined measurements of crop yield, total aboveground biomass (AGB) and light interception over a 4-year crop rotation cycle from 2015 to 2018 in a long-term experiment in Denmark with arable organic and conventional cropping systems. These cropping systems comprise one conventional (CGL) and two organic (OGL and OGC) crop rotations, where CGL and OGL had three spring cereal and one grain legume crop (faba bean) in the rotation, and the faba bean was in OGC replaced with grass-clover. All crop rotations were grown with and without the use of cover crops, and the organic systems were grown with and without the manure application. The light interception was calculated from measurements of spectral reflectance, and this allowed the AGB to be decomposed into accumulated intercepted PAR (AIPAR) and radiation use efficiency (RUE).The conventional cropping system (CGL) had significantly greater AGB, AIPAR and RUE compared with the corresponding organic, grain legume-based system (OGL). AIPAR of the organic grass-clover-based cropping system (OGC) was greater than CGL, although the contrary conclusion was found in AGB and RUE. Across crops, RUE was greatest for cereals and smallest for faba bean and grass-clover. AIPAR was consistently greatest for grass-clover, and both grass-clover and faba bean had smaller variability in AIPAR between years and treatments than the cereal crops. Cover crops significantly increased AGB and AIPAR in the organic cropping systems but not in CGL. RUE was not significantly affected by the inclusion of cover crops. The use of manure in the organic systems increased AGB, AIPAR and RUE. The results show that AIPAR can be higher in organic cropping systems compared with conventional cropping systems, but this is not translated into a greater yield of cereal crops. There is, therefore, a need for novel approaches to management and the use of biomass in organic cropping systems for increasing yields for feed and food, and which sustains soil fertility.

Agriculture is a major driver of climate change, particularly when all indirect emission sources are accounted for. Mitigation options targeted on one process are often proposed, ignoring their secondary effects on the overall greenhouse gas balance. Integrative methodologies such as life cycle assessment (LCA) are often applied without adjusting emission factors to specific site characteristics. Here, we used LCA to calculate the global warming potential of 38 pairs of organic and conventional herbaceous cropping systems and products in Spain. Crop products included rainfed cereals and pulses, rice, open-air vegetables, and greenhouse vegetables. We used data from farmer interviews and published conversion factors. Our results show that the emission balances were dominated by fossil fuel use rather than by direct field emissions. Organic management reduced crop emissions by 36–65 %, with the exception of rice showing an increase of 8 % due to methane generation. Product-based emissions of organic crops were also lower by 30 % on average, except for rice.

This work shows the results of trials carried out over three years (2006-2008) within the national networks of durum wheat grown under conventional and organic cropping systems in six representative locations of the main cultivation areas of Italy. The main aspects of grain yield and grain quality were analyzed, particularly assessing the hygienic health status of the grain in relation to the possible presence of deoxynivalenol (DON) contamination. DON is considered the most common trichothecene mycotoxin found in the wheat grain, causing significant reductions in grain yield and adverse effects for human or animal consumption. In the studied period the average grain yields were quite interesting both in conventional samples (5.85 t ha-1) and in organic ones (4.91 t ha-1). As expected, the organic yields were significantly different(-16%). However, in the southern locations the same differences were lower (-5%), thus emphasizing the limited impact of the higher inputs of the conventional cropping in these environments. The reduced nitrogen input is notoriously the most critical point of organic wheat, because the protein content is the most sensitive parameter of grain quality. The protein content was significantly different among year, fields location and cropping system, but not among their interactions. Grain protein content in organic wheat was lower than in conventional one all over the three years; anyway, differences were somewhat limited (only about 1% in the southern locations and 0.5% in central Italy). Among cultivars no significant differences in the protein content were recorded. Mean levels of DON contamination during the study period were generally lower, with only a sample exceeding the legal limit of 1750 ppb. Among the main factors, year and location (and their interaction) had a strong influence on DON contamination, accounting for 75% of the observed variability. DON levels in 2008 at Papiano-PG were dramatically high; the strong influence of the year-location interaction may be due to this fact. Cropping system and cultivar, although significant, had a low influence; however, their interaction accounted for 13% of total variance. Cropping system – location interaction accounted for 5% of the total variability. Very low levels of DON were detected in the southern locations with both cropping systems; the lower levels were recorded in organic wheat samples. In the central Italy areas DON could represent a potential hazard, but even in these organically cropped environments wheat gave the best results. Lower concentrations of DON were detected in organic wheat samples, either in less favourable years for the occurrence of Fusarium (2006 and 2007) and in the more favourable one (2008). Regarding the role of the varietal choice, Creso revealed to be the less susceptible to DON contamination, probably as it is the best adapted to the areas of the Central Italy, where Fusarium is more widespread.

Introduction: Two recent papers, Delbridge et al. (2011) and Delbridge et al. (2013), have used agricultural trial data from Southwestern Minnesota to compare the profitability of organic and conventional cropping systems. These analyses found that organic cropping systems can earn more on a per-hectare basis (Delbridge et al., 2011) and a whole-farm basis (Delbridge et al., 2013) than a conventional cropping system, given the same machinery and labor endowments. However, in the years since the collection of the agricultural trial data on which these analyses are based, conventional grain prices have reached record levels and some organic crop producers have begun to abandon their organic certification and return to conventional production. The strong performance of conventional crop producers in 2011-2012 raises the question: would the results of these analyses hold if they included more recent data? This paper answers this question by updating the analyses performed by Delbridge et al. (2011) and Delbridge et al. (2013) with 2011 and 2012 yield and management data from the Variable Input Crop Management Systems (VICMS) trial and more recent input and output price information.

Edaphic cyanobacteria and algae have been extensively studied in dryland soils because they play key roles in the formation of biological soil crusts and the stabilization of soil surfaces. Yet, in temperate agricultural crop soils, little is understood about the functional significance of indigenous photosynthetic microbial communities for various soil processes. This study investigated how indigenous soil algae and cyanobacteria affected topsoil aggregate stability in cereal cropping systems. Topsoil aggregates from conventional and organic cropping systems were incubated in microcosms under dark or photoperiodic conditions with or without a treatment with an herbicide (isoproturon). Physicochemical parameters (bound exopolysaccharides, organic carbon) and microbial parameters (esterase activity, chlorophyll a biomass, and pigment profiles) were measured for incubated aggregates. Aggregate stability were analyzed on the basis of aggregate size distribution and the mean weight diameter (MWD) index, resulting from disaggregation tests. Soil photosynthetic microbial biomass (chl a) was strongly and positively correlated with aggregate stability indicators. The development of microalgae crusts in photoperiodic conditions induced a strong increase of the largest aggregates (>2 mm), as compared to dark conditions (up to 10.6 fold and 27.1 fold, in soil from organic and conventional cropping systems, respectively). Concomitantly, the MWD significantly increased by 2.4 fold and 4.2 fold, for soil from organic and conventional cropping systems. Soil microalgae may have operated directly via biochemical mechanisms, by producing exopolymeric matrices surrounding soil aggregates (bound exopolysaccharides: 0.39–0.45 μg C g−1 soil), and via biophysical mechanisms, where filamentous living microbiota enmeshed soil aggregates. In addition, they may have acted indirectly by stimulating heterotrophic microbial communities, as revealed by the positive effect of microalgal growth on total microbial activity. The herbicide treatment negatively impacted soil microalgal community, resulting in significant decreases of the MWD of the conventional soil aggregates (up to −42% of the value in light treatment). This study underscores that indigenous edaphic algae and cyanobacteria can promote aggregate formation, by forming photosynthetic microbiotic crusts, thus improving the structural stability of topsoil, in temperate croplands. However, the herbicide uses can impair the functional abilities of algal and cyanobacterial communities in agricultural soils.Originality/SignificanceEdaphic algal and cyanobacterial communities are known to form photosynthetic microbial crusts in arid soils, where they drive key ecosystem functions. Although less well characterized, such communities are also transiently abundant in temperate and mesic cropped soils. This microcosm study investigated the communities’ functional significance in topsoil aggregate formation and stabilization in two temperate cropping systems. Overall, our results showed that the development of indigenous microalgal communities under our experimental conditions drove higher structural stability in topsoil aggregates in temperate cropland soils. Also, herbicide use affected photosynthetic microbial communities and consequently impaired soil aggregation.

Modern agriculture should increase crop sustainability while feeding the growing population. The organic cropping system has emerged as an interesting alternative and more sustainable crop management than conventional one. Unfortunately, the current yield gap between organic and conventional systems is significant for most crops, and this limits the organic system’s value. Hence, the objective of this study was to investigate biomass production and partitioning of processing tomato genotypes cultivated in organic vs conventional cropping systems in a processing tomato growing area in the Mediterranean. From 2010–2012, field trials were carried out in two farms in Southern Italy. At the end of the crop cycle and in average among years, processing tomato cultivated in organic cropping system showed reductions of: total biomass dry weight (−25%), leaf area (−36%) and radiation use efficiency (−24%). The biomass distribution to fruits and leaves was highly similar under both managements, while a higher fraction of total biomass was allocated to stems (+34%) and to roots (+41%) in the organic cropping system. In the studied environment, a major cause of different fruit dry weight and, consequently, of yield gap between organic and conventional cropping systems was the reduction of the source, i.e. the lower leaf area, that led to a reduction of total biomass dry weight.

Rye is a cereal which is very much demanded at the market, for making a special kind of bread, but it is little grown in Serbia. The aim of this paper is to investigate possibilities of organic growing of winter rye, comparing with the conventional one, in agroecological conditions of Valjevo hilly region during 2008/2009 and 2009/2010 cropping seasons. The trial was set up in a village of Kotesica, on soil which had not been used for agriculture for 7 years. In organic cropping system three combinations of microbiological fertiliser baktofil with zeolite and hydrogel were used prior to sowing. Half of each plot was treated with foliar microbiological fertiliser Slavol during crop growing period. In conventional cropping system three variants with mineral fertilisers were included: NPK, NPK+zeolite, NPK+hydrogel. Results of the yield obtained in the experiment showed a significant difference between two seasons, 2008/2009 and 2009/2010. In comparison with the control, the treatments in an organic cropping system resulted with statistically insignificant differences for mean values in both years, while the mean in conventional cropping system has significantly higher yield of winter rye. Organic cropping system under conditions of Valjevo hilly region did not give significantly lower rye yield compared with the conventional one in a moderate growing season such was 2008/2009. The combination of soil microbiological fertiliser (Baktofil) with foliar fertiliser (Slavol) and zeolite gave the highest winter rye grain yield in all other treatments in the second year of investigation. In a very wet season (2009/2010) mineral fertiliser NPK showed an advantage, especially in combinations with zeolite, and this treatment can be recommended.

The effects of four conventional and four organic cropping systems on the crop yield and yield quality, on the microbial activity of soil, on weeds, plant diseases, insect pests and earthworms were compared in a field experiment on the Suitia Experimental Farm in Southern Finland in 1982—1988. In the conventional cropping systems, industrial fertilisers and chemical pesticides were used according to practices adopted on actual farms in Southern Finland. In the organic cropping systems, plant nutrition was based on biological N fixation by legumes and organic manures. No chemical pesticides were used. The average yield of barley in organic cropping varied between one quarter and half of that in conventional cropping. The yields of winter wheat, oats and potato were about 40 % of those obtained conventionally. The yields of clover-grass leys in organic farming were similar to those of grass-leys in the conventional system. Unfortunately, the clover-grass leys outwintered after the first year. The primary reason for the poor crop growth in the organic cropping systems was apparently the acute N deficiency caused by poor performance of legumes, low N content of organic manures and N losses in anaerobic conditions often occurring during winter and early spring. Pronounced soil compaction and anaerobic conditions in organic cropping systems had a harmful effect on the microbiological activity of soil as well as on earthworms. Weeds, plant diseases and insects were not a remarkable problem in any of the cropping systems.

The effects of organic versus conventional farming practices on wheat functional and nutritional characteristics were compared. Soft white winter wheat and hard red spring wheat were obtained from multiyear replicated field plots near Pullman, Washington, and Bozeman, Montana. Test weight, kernel weight, and kernel diameter tended to be greater in both soft and hard organic wheat than in conventional wheat in the Pullman studies. Phenolic content and total antioxidant capacity tended to be lower in organic than in conventional wheat. Flour ash, P, and Mg contents in whole wheat flour varied in parallel among cropping systems, but levels were not consistently associated with either organic or conventional cropping systems. Protein contents of whole wheat and refined flours were similar in organic and conventional wheat from Pullman when fertility levels were similar. Higher fertility was associated with higher protein content in both organic and conventional cropping systems. Soft wheat flour from a low-fertility organic cropping system had lower sodium carbonate, lactic acid, and sucrose solvent retention capacities, lower protein content, and greater cookie diameter and cake volume than soft wheat flour from the higher fertility organic and conventional cropping systems; the change in end-product quality was significant in one out of two crop years. In the Bozeman hard wheat studies, higher fertility in both organic and conventional cropping systems tended to increase protein content and bread loaf volume. Results indicated that neither organic nor conventional cropping systems were associated with substantially improved mineral and antioxidant nutritional properties, and end-use quality of wheat was more strongly associated with fertility level than with organic versus conventional cropping systems.

بیماری پوسیدگی ریزوپوسی و نقطه سیاه از مهم ترین بیماری های انباری در گوجه فرنگی می باشند. به منظور بررسی توانایی چند گیاه دارویی بر ماندگاری و کنترل قارچ های عامل پوسیدگی انباری Rhizopus nigricans) و Alternaria alternate) در گوجه فرنگی های تولید شده در سامانه های کشاورزی رایج و زیستی، آزمایشی به صورت فاکتوریل در قالب طرح کاملاً تصادفی با 14 تیمار و سه تکرار در دانشگاه فردوسی مشهد در سال 1389 اجرا شد. دو سامانه تولید شامل گوجه فرنگی رایج و زیستی (ارگانیک) و شش گونه گیاهی (آویشن (Thymus vulgaris L.)، پونه (Mentha pulegium L.)، نعناع فلفلی (Mentha piperita L.)، اکالیپتوس (Eucalyptus globules L.)، کرچک (Ricinus communis L.) و گوجه فرنگی (Lycopersicom esculentum Mill.)) به همراه تیمار شاهد به ترتیب عامل اول و دوم در این آزمایش بودند. بر اساس نتایج آزمون غیر پارامتری کروسکال– والیس، تفاوت معنی داری بین سامانه های تولید گوجه فرنگی های ارگانیک با نوع غیرارگانیک آن از نظر سرعت پوسیدگی انباری ناشی از رشد قارچ های بیماری زا مشاهده شد. به طوری که در گوجه فرنگی های ارگانیک، سرعت پوسیدگی (47/1 عدد میوه در هفته) تا حدود 20 درصد کمتر از نوع غیرارگانیک آن بود. نتایج حاصل از آنالیز غیرپارامتری گونه های گیاهی نیز حاکی از وجود تفاوت بین این گونه ها از نظر تأثیر بر سرعت پوسیدگی انباری در گوجه فرنگی بود؛ به طوری که به جز کرچک و گوجه فرنگی، سایر گیاهان دارویی منجر به کاهش معنی دار سرعت رشد و توسعه قارچ های بیماری زا در انبار شدند.

Nine cultivars of winter wheat were compared in organic and conventional crop rotation systems. Bread-making quality was evaluated using three parameters [thousand-kernel weight (TKW) in g, volume weight in g/l, protein content in %]. Grain yield, TKW and protein content of winter wheat in organic cropping system were significantly lower as compared to any intensity in conventional cropping system. However, clover as a preceding crop to winter wheat in organic crop rotation ensured a sufficient amount of nitrogen for grain yield, which was 6.72 t/ha on average of the three years. The requirement of the Czech national standard for bread wheat minimum value of protein content (11.5%) was met in conventional crop rotation in all cases. Average value of protein content in organic crop rotation met this limit too, but it was below the required value in two cases. The required value (760 g/l) of volume weight was met in majority of cases in organic crop rotation. The following species of the genus <I>Fusarium were</I> found: <I>F. culmorum, F. graminearum, F. poae</I> and <I>F. avenaceum</I>. All samples were screened for the content of deoxynivalenol (DON). There was no significant difference in the DON content between winter wheat grain from organic crop rotation and conventional crop rotation at high intensity.

Producing safe and nutritious food for consumers and ensuring profitability and sustainability of farming enterprises through environmentally friendly agronomic practices are some of the major challenges facing agriculture today. Field studies were conducted in 2001 and 2002 to evaluate the effect of conventional (chemical-intensive) monocropping, transitional (reduced-synthetic input), and an organic (non-synthetic input) multiple cropping systems on sweet potato (Ipomoea batatas (L.) Lam) yield and quality, as well as soil properties. The studies were conducted on a Dexter silt loam soil in northern Mississippi. In both years No. I sweetpotato yield was greatest for the transitional and organic cropping systems and lowest for the conventional cropping system. In 2001, cropping system did not affect plant survival. In 2002, plant survival was greatest for the conventional cropping system and lowest for the organic cropping system. Soil extractable nutrient levels prior to planting (preplant soil fertility) were very high for Mg, high for P and Ca, medium for S, and low for K. Final post-harvest soil levels after the 2nd year: the content of Mg was very high for the three cropping systems, and high for P, K and Ca. Sulfur was high for the organic cropping system, and medium for the conventional and transitional cropping systems. In 2001, sweetpotato P content was greatest for the conventional cropping system and lowest for the transitional cropping system. Both Ca and Mg were greatest for the conventional cropping system but were not different from the transitional cropping system. Potassium was greatest for the organic cropping system and lowest for the transitional cropping system. Both N and S were not affected by cropping systems. In 2002, N content in roots was greatest for the conventional and organic cropping systems and lowest for the transitional cropping system. The other nutrients were not affected by cropping system. Sweetpotato roots under the conventional cropping system had the greatest protein, fat and ash contents, whereas crude fiber was the greatest for roots under the transitional cropping system. Root dry matter was greatest for the organic cropping system and lowest for the conventional cropping system. Data suggest that Beauregard sweetpotato cultivar can be successfully grown on a Delta silt loam soil in northern Mississippi. Where the production of No. 1 marketable sweetpotato roots are desired, both the transitional and organic cropping systems are recommended over the conventional cropping system. While the conventional cropping system will enhance root protein, fat and ash contents more than the transitional and organic cropping systems, both cropping systems will, respectively, enhance crude fiber and dry matter more than the conventional cropping system.

Conventional cropping systems (CCSs) rely heavily on large-scale and intensive crop production, using mechanical tillage and synthetic inputs such as chemical fertilizers and pesticides. While these methods can be economically beneficial, they can also be environmentally destructive. Organic cropping systems (OCSs), on the other hand, offer a more sustainable approach with less harmful effects on the environment. CCSs exhibit higher prevalence rates compared to OCSs. This means that there is less research on soil processes in organic fields and the impact of these processes on soil quality. In this study, we aim to assess the functional potential of soils by analyzing their ability to transform carbon, nitrogen, phosphorus, and sulfur. We use shotgun sequencing data to predict the activities of enzymes involved in these cycles. These predictions are then compared to the actual enzyme activity measured in the soil. The objects of study are samples of Chernozem soil from fields cultivated for 11 years using the OCS method and 20 years using the CCS method. It was found that the chemical properties of the studied soils differed significantly in terms of total carbon and total and available nitrogen and phosphorus. Except for phosphorus, the concentration of these elements was significantly higher in the CCS than in the OCS. We assessed the quality of the soils by measuring their enzymatic activities. A comparison of the two cropping systems showed that the activities of the enzymes involved in the C, N, P, and S cycles were, on average, 2.91, 1.89, 1.74, and 1.86 times higher in the CCS than in the OCS, respectively. A two-way PERMANOVA showed that the cropping system was the main variable (F = 14.978, p < 0.01) determining the enzymatic activity of soils, followed by soil depth (F = 9.6079, p < 0.01). We used shotgun sequencing to identify functional genes involved in C, N, P, and S metabolism, as well as genes encoding the measured soil enzymes. Compared to the OCS, the CCS soils had a higher relative abundance of genes involved in N-conversion (log2(FC) +0.22), C-conversion (log2(FC) +0.14), P-conversion (log2(FC) +0.47), and S-conversion (log2(FC) +0.24). At the same time, we found no significant differences between the systems in the relative abundance of genes encoding the measured soil enzymes. Thus, the comparison of the two cropping systems studied showed that the soil microbiome in the CCS has a greater functional potential to support biogeochemical cycles of the key biogenic elements than in the OCS. In addition, this study links the data on the representation of functional genes with the actual activity of enzymes. Based on the results, it would be helpful to focus more specifically on actual enzyme activity or to combine several indicators to obtain a more accurate understanding of soil quality.

At Suitia, Southern Finland, weed populations in different crop rotations at conventional and organic cropping systems were investigated in 1982—1988. The number of weeds and the dry matter yields of weeds were greater in organic cropping (on average 324 weeds/m2 and 425 kg DM/ha) compared to conventional cropping (94 weeds/m2 and 61 kg DM/ha). There were least weeds in the conventionally cultivated ley. The first year, clover ley in organic cropping prevented the growth of weeds as well as the grass ley in conventional cropping. Overwintering damages in organically cultivated leys increased the amounts of weeds in the following ley years. Organically cultivated winter wheat reduced the amount and weight of weeds almost as well as conventionally cultivated winter wheat although its biomass was three-fourths of the conventionally cultivated winter wheat. The biomass of organically cultivated barley later on in the rotations was only one-fifth of the conventionally cultivated barley and had five times more weeds. In conventional cropping, the number of weeds in almost all weed species was decreased or stayed at the same level during the experiment. In organic cropping, the number of most weeds in weed species increased from the level for 1982. Most increased Stellaria media, Fallopio convolvulus, Lamium sp and Chenopodium album.