Legumes have been shown to enhance bioavailability of phosphorus (P) from sparingly soluble pools, yet this functional trait remains underutilized in agriculture, and is untested at decadal scales. Management and legume presence effects on temporal soil properties were evaluated in a 17-year field crop experiment using soil samples collected in 1992, 2000 and 2006. Management systems compared included: (1) conventional corn–soybean–wheat rotation (C–S–W), (2) organic (C–S–W+red clover), (3) alfalfa and (4) early successional field. To evaluate the effects of long-term management versus recent management (residues and P fertilizer) on P and bio-availability to soybean, subplots of soybean were established with and without P-fertilizer (30 kg P ha−1), and compared to subplots and main plot with the long-term system. We evaluated soil properties (C, total P, Bray extractable inorganic P, particulate organic matter phosphorus) and soybean P uptake, biomass and yield. Recent fertilizer P inputs had no detectable influence on soil P, and total soil P stayed stable at ~350 mg P kg−1, whereas inorganic P (Pi) declined from an initial value of 54 to an average of 35 mg P kg−1. A P balance was constructed and showed a net loss of −96.7 kg P ha−1 yr−1 for the organic system, yet Bray-Pi and soybean P uptake were maintained under organic production at similar levels to the conventional, fertilized system. Particulate organic matter P was 57, 82 and 128% higher in organic, alfalfa and successional treatments, respectively, compared to conventional. A similar pattern was observed for soil C, soybean yield and bioavailable P, which were 20–50% higher in the organic, alfalfa and successional systems relative to conventional. This study provides evidence that long-term management history influences bioavailability of P.

Open-air crops are important in Spanish horticulture. The limited number of herbicide active ingredients in minor crops, the waste problem of polyethylene (PE) plastic mulch and the high prices of biodegradable plastics leave hand-weeding and mechanical weed control as the most viable weed control methods. Different tools have been tested in northern European countries but their performance remains unknown in the edaphoclimatic situation of southern Europe. The objective of this work was to test novel physical weed control methods on processing tomato in northeastern Spain compared with other effective control methods, i.e., plastic and paper mulches. A first sequence of field trials was established from 2005 to 2008 at Zaragoza (Spain) to select the best physical control methods out of flamer, torsion weeder, finger weeder, flex-tine harrow and brush hoe used alone or in combination. The best method was the brush hoe which was then compared from 2009 to 2011 with PE mulch, biodegradable plastic mulch and paper mulch. Flamer, flex-tine harrow, torsion weeder and finger weeder performed quite irregularly due to crusty soil conditions and needed additional tools or repeated treatments to increase weed control efficacy. The brush hoe performed best in this soil situation working at about 5 cm depth. Weed biomass reduction was higher than 80% in 6 out of 7 years and similar yield was obtained in the brushed plots compared to the yield obtained with PE, biodegradable plastic and paper mulch. The brush hoe is thus a suitable option for weed control in processing tomato while the other tools were too weak to control aggressive summer weeds in the tested conditions.

In Sehoul, Morocco, the use of marginal land for agriculture became a necessity for the local population due to increased poverty and the occupation of the best land by new owners. Desertification poses an additional threat to agricultural production on marginal slopes, which are often stony and degraded. In a participatory process embedded in the EU DESIRE research project, potential sustainable land management measures were selected to address land degradation and desertification. Promising experiences with no-tillage practices elsewhere in Morocco had motivated the Moroccan government to promote conservation agriculture throughout the country. This combination of crop rotation, minimal soil disturbance and soil cover maintenance, however, had not yet been tested on sloping degraded land. Field trials of grazing enclosure combined with no or minimum tillage were conducted on the plots of two farmers, and trial results were analyzed based on stakeholders’ criteria. Results suggest that increased soil cover with barley residues improved rainwater use efficiency and yields only slightly, although soil water was generally enhanced. Soil moisture measurements revealed that no-tillage was favorable mainly at soil depths of 5 cm and in connection with low-rainfall events (<20 mm); under these circumstances, moisture content was generally higher under no-tillage than under conventional tillage. Moreover, stakeholder discussion confirmed that farmers in Sehoul remain primarily interested in animal husbandry and are reluctant to change the current grazing system. Implementation of conservation agriculture is thus challenged both by the degraded, sloping and stony nature of the land, and by the socio-economic circumstances in Sehoul.

The millions of food insecure people in India are not solely due to inadequate food production, but also because some people are simply too poor to buy food. This study assessed how a large-scale conversion from conventional to organic production would impact on the economics of marginal and small farmers in Tamil Nadu and Madhya Pradesh, and on the total food production in these states. This study also considered a situation where fertilizer subsidies would be discontinued, with farmers having to carry the full cost of fertilizer. Results show that conversion to organic improved the economic situation of farmers although food production was reduced by 3–5% in the organic situation. Thus, the estimated economic values were higher in the organic system (5–40% in fertilizer subsidy scenario and 22–132% in no fertilizer subsidy scenario) than in the conventional system, whereas the total state-level food productions were lowered by 3–5% in the organic compared to the conventional system. Food production was higher when rainfed, and lower in the irrigated situation in the large-scale organic scenario. Although the study addresses short-term perspectives of large-scale conversion to organic farming, more research is needed to understand the long-term impact of organic conversion on food production, nutrient supply, food security and poverty reduction.

Among infusions of green teabags and leafy green teas from organic and non-organic production systems we measured and compared the content of phenolic acids, flavonols and total polyphenols by spectrophotometry, the content of tannins by titration and the content of caffeine by high-performance liquid chromatography (HPLC). In addition, the antioxidant activity of the infusions was determined by spectrophotometry. The results obtained have shown that organic teas contained significantly more flavonols and tannins. However, the content of phenolic acids was higher in non-organic teas. The teas from organic and non-organic production did not differ in terms of total polyphenol content and antioxidant activity. There were no differences in leaf teas in relation to the teabags in contents of phenolic acids, tannins and total polyphenols. Organic teas had higher content of catechin C than the non-organic ones, but at the same time non-organic teas had more epigallocatechin 3-gallate (EGCG) in comparison to organic teas. Epigallocatechin (EGC) and epicatechin (EC) were not found to be different between the two groups of tea. Catechin was found to be significantly higher in teabags, while the EGCG was higher in leaf teas. The reason for this may be the oxidation of teabags, which have a greater exposed surface area. There was no appreciable effect of the form of tea on the content of tannins, caffeine, flavonols, phenolic acids, total polyphenols, EGC and EC as well as the antioxidant activity of the tea infusions examined.

In temperate regions, reduced tillage is still not broadly accepted in organic farming although the guidelines often recommend the reduction of tillage intensity. During the years 5–7 of a long-term experiment, we studied the effects of the three tillage systems moldboard plowing (MP, soil inversion to 30 cm depth), two-layer plowing (TP, inversion to 15 cm, loosening to 30 cm) and layer cultivation (LC, loosening to 30 cm) on soil nutrients, nutrient content of barley, rye and associated weeds, and yield on a clay loam soil. Crops were cultivated within a five-course crop rotation consisting of green fallow, winter wheat, field peas, winter rye and spring barley; no additional fertilizers were applied. Tillage affected only soil nitrate under barley, which decreased with decreasing tillage intensity. Soil humus, phosphorus (P) and potassium (K) were unaffected by tillage under both crops. Barley shoot nitrogen content was significantly influenced by tillage, with, across years, 38 and 83% higher values under MP than under TP or LC, respectively. Weeds in barley had a higher P and K content at LC than at MP or TP. This resulted, across years, in 73% higher barley yields in MP than in LC. The TP showed a 29% higher barley yield than the LC. Tillage methods had no effect on rye nutrient contents, rye yields or on weeds associated with rye. The significant interaction between tillage and year for rye yield suggests that weather conditions in a given year (e.g., amount of rainfall) can considerably alter the effect of reduced tillage.

Growing populations and a constrained fossil-manufactured energy supply present a major challenge for society and there is a real need to develop forms of agriculture that are less dependent on finite energy sources. It has been suggested that organic agriculture can provide a more energy efficient approach due to its focus on sustainable production methods. This review has investigated the extent to which this is true for a range of farming systems. Data from about 50 studies were reviewed with results suggesting that organic farming performs better than conventional for nearly all crop types when energy use is expressed on a unit of area basis. Results are more variable per unit of product due to the lower yield for most organic crops. For livestock, ruminant production systems tend to be more energy efficient under organic management due to the production of forage in grass–clover leys. Conversely, organic poultry tend to perform worse in terms of energy use as a result of higher feed conversion ratios and mortality rates compared to conventional fully housed or free-range systems. With regard to energy sources, there is some evidence that organic farms use more renewable energy and have less of an impact on natural ecosystems. Human energy requirements on organic farms are also higher as a result of greater system diversity and manual weed control. Overall this review has found that most organic farming systems are more energy efficient than their conventional counterparts, although there are some notable exceptions.