The sustainability of a farm system greatly relies on fertilizers and other inputs. Soil factors such as texture and local rainfall, along with management-related factors such as soil organic matter, aggregate stability and agronomic practices, have much greater influence on the sustainability of any given farm than do the type or amount of soil amendments. Growers use a wide variety of practices to maintain or improve soil health in organic vegetable production systems. These practices generally are part of long-term, site-specific management programs that aim at developing fertile and biologically active soils that readily capture and store water and nutrients, have good tilth, and suppress plant diseases. Field experiments were conducted in 2005 and 2006 in Mashhad, Iran, to study the effects of organic amendments, synthetic fertilizers and compost extracts on crop health, productivity and storability of tomato (Lycopersicon esculentum Mill.). Treatments included different fertilizers of cattle, sheep and poultry manures, green-waste and household composts and chemical fertilizers of urea and superphosphate; and five aqueous extracts from cattle manure, poultry manures, green-waste, and household composts plus water as control. Our results show that application of poultry manure showed lower disease incidence, as shown by 80% healthy tomato, compared with the other fertilizers. However, the organic fertilizers used did not give higher yields compared with chemical fertilizers. Sheep manure and chemical fertilizers led to the highest total tomato yield. Marketable yield was highest in poultry manures, of 16 t/ha, and lowest in chemical fertilizer, of 7 t/ha, 6 weeks after storage. The effect of aqueous extracts was not significant on either crop health or tomato yield and the results were inconsistent. The compost made of poultry manure therefore appears to be a promising ecological alternative to classical fertilizers. compost / crop health / lycopersicum esculentum / manure / marketable yield

The enemy release hypothesis (ERH) of plant invasion asserts that natural enemies limit populations of invasive plants more strongly in native ranges than in non‐native ranges. Despite considerable empirical attention, few studies have directly tested this idea, especially with respect to generalist herbivores. This knowledge gap is important because escaping the effects of generalists is a critical aspect of the ERH that may help explain successful plant invasions. Here, we used consumer exclosures and seed addition experiments to contrast the effects of granivorous rodents (an important guild of generalists) on the establishment of cheatgrass ( Bromus tectorum ) in western Asia, where cheatgrass is native, versus the Great Basin Desert, USA, where cheatgrass is exotic and highly invasive. Consistent with the ERH, rodent foraging reduced cheatgrass establishment by nearly 60% in western Asia but had no effect in the Great Basin. This main result corresponded with a region‐specific foraging pattern: rodents in the Great Basin but not western Asia generally avoided seeds from cheatgrass relative to seeds from native competitors. Our results suggest that enemy release from the effects of an important guild of generalists may contribute to the explosive success of cheatgrass in the Great Basin. These findings corroborate classic theory on enemy release and expand our understanding of how generalists can influence the trajectory of exotic plant invasions.

Purpose Four different types of composts were assessed in two methods of application for their potential to support organic tomato yield. Methods A 2-year experiment was conducted using four different soil conditioners: cow manure (CM), household compost (HC), spent mushroom compost (SMC), and vermicompost (VC). Three different application rates (10, 20, and 30 t ha −1 for all composts except VC and 3, 6, and 9 t ha −1 for VC) were included as a second factor. Two methods of fertilizer placement (as a row behind the root area and broadcast on the field) were considered as a third factor. Results The yield was influenced by different soil conditioners and placement method in the first year; in the second year, just interactions were significantly different. Treatments with CM showed significantly higher tomato yield in the first year (103 t ha −1) compared to other composts, but in the second year, SMC produced a higher yield (58 t ha −1). The experiment indicated that the treatment with CM in high level with broadcast application had higher dry matter (DM) production (3.1 t ha −1) in 2014, and treatment with CM in low rate and broadcast application had higher DM production (5.8 t ha −1) in 2015. Conclusion Compost broadcast on the plots showed a higher yield production in case of similar rates and compost type. The proper rate of compost application is dependent on the method of compost placement.

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Due to having a short half-life and novel site of action, the herbicidal potential of natural compounds are lionized. Coumarin is a secondary metabolite from Lavandula sp., family Lamiacae. The impact of eight concentrations of coumarin (0, 100, 200, 400, 800, 1600, 3200 and 6400 ppm) were separately used as a pre-plant incorporated into soil on six plant species under greenhouse conditions. Generally, coumarin had phytotoxic effect against all plant species. The phytotoxic effect was concentration-dependent. The high concentrations could inhibit the emergence of seedlings (probably by stopping germination of seeds). Based on ED50 parameter, the ranking of plant species for tolerance to coumarin was S. halepense > Z. mays > C. album > A. retroflexus > E. cruss-gali > P. oleracea. Based on selectivity index, coumarin at a concentration of 365.69 ppm can control P. oleracea without damaging Z. mays, whereas any concentration it cannot control other weeds without damaging Z. mays.

Russian Olive, Elaeagnus angustifolia was introduced into North America primarily as a wind break and shade tree. Today it is listed as a noxious weed in the U.S. and Canada. During field surveys in the native range, the eriophyid mite, Aceria angustifoliae was identified as a promising biological control agent. Results from no-choice and open-field tests suggest that this is a highly specialized herbivore and that the risk to non-target plants in North America is negligible. The impact study revealed significant reductions in fruit set, which will likely translate to a reduction in long-distance dispersal in the invaded range.

Article InformationIn order to investigate RAE and RUE in alternative intercropping of wheat-canola, an experiment was carried out in a field located in Shirvan in 2013-2014. The experiment plan was arranged in factorial-RCBD with 3 replications. Treatments included 3 different ratio of density (for wheat T =250, T =300 1 2 2 and T =350; for canola C =80, C =100 and C =120 plant/m ) and 7 planting ratios (D0=canola showed that density of planting ratio and their interactions had significant effects on absorption efficiency, seed yield and RUE. In intercropping treatments, seed yield of canola was more than monoculture, but it was less than of wheat monoculture. The more seed yield of wheat was gained from canola.