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Vegetation in natural desert and agro-ecosystems was investigated in the middle sector of Egypt. The vegetation was classified by the Two Way Indicator Species Analysis technique (TWINSPAN) into nine vegetational groups representing seven habitat types: desert, fallow land, winter crops of old cultivated land, summer crops of old cultivated land, Citrus orchards, winter crops of reclaimed land, and summer crops of reclaimed land. Detrended Canonical Correspondence Analysis (DCCA) demonstrates that soil factors especially soil texture, CaCO3, organic carbon and electric conductivity contribute significantly to the distribution of species. In all habitat types, species diversity is higher in winter than in summer season. The weed species diversity is greater in the reclaimed areas compared to the old cultivated land and in winter crops than in summer ones.
Most Hungarian ecosystems are agro-ecosystems dominated by crops. In these agroecosystems small game has a secondary, but nevertheless very important role. On the one hand, the wild fauna figures are an indicator of the sustainability of a system. On the other hand, game management and hunting are traditional activities. Hunting can be regarded as a special kind of agriculture and small game management takes place on agricultural land, so more should be known about the connection between ecosystem components, such as climatic factors, crops and small game populations, for example that of hare. Data on the land use in Hungary were collected between 1960 and 2006. The area and yield of 30 field crops and various meteorological parameters were examined, as well as hare populations. The results suggest that in general the magnitude of crop areas had a stronger effect than the yield, while weather parameters had the weakest impact on the hare population.
The four methods of rice crop establishment viz., conventional transplanting, bed transplanting, furrow transplanting and puddled direct seeding were evaluated during two wet seasons to determine their effect on the abundance and the diversity of natural enemy populations in rice agro-ecosystem. Population counts of natural enemy fauna (insect predators/parasitoids and spiders) were recorded from randomly selected two quadrates of 1 m2 per replication at 10 days intervals starting from 40 days up to 110 days after crop establishment. Over the years in all the crop establishment methods insect predator/parasitoid population of (Braconidae, Ichneumonidae, Coenagrionidae, Coccinellidae and Carabidae) were significantly more in puddled direct seeding followed by transplanted crop than other methods. Spider predator population (Tetragnathidae, Araneidae, Oxyopidae, Salticidae, Lycosidae, Metidae and Tomisidae) were significantly more in bed transplanting than in other crop establishment methods. Overall natural enemy fauna (insect predators/parasitoids and spider predators) were significantly more in bed transplanting and puddled direct seeding. The diversity index across years and observation days was high in case of bed transplanting, which was due to high evenness index in the crop establishment method.
About 2500 arthropod species immigrate, or carried by wind, or introduced by man in the orchards, under Hungarian climatic conditions. However, the number of the apple pest species is approximately 30. Owing to the effect of the relationships among the plant-phytophagous-zoophagous species those could colonize the orchard for which the apple provides suitable food sources and whose populations are not regulated or are regulated by a weak efficiency by parasitoids and predators. These populations create the primary pest communities. When the individual number of the parasitoid and predator species is reduced by the broad-spectrum insecticides, the population density of those phytophagous species could increase whose populations was restricted up to that time. In this case the secondary pest communities could develop. The integrated pest management provides the possibilities to solve the problems caused by the regular use of broad-spectrum insecticides. The real requirement is to find and to harmonize those methods which regulate the population dynamics of the species of the primary pest communities.
Different long-term experiments were carried on chernozem (Debrecen) and loamy (Hajdúböszörmény) soils. They included the most important agrotechnical, biological (hybrid) and agroecological (crop year, soil) factors in maize production. This paper evaluated the results of polyfactorial long-term experiments. For the maize the most favourable crop rotation was winter wheat (in a tri-culture) with an N 60–120, P2O5 60–70, K2O and 90–110 kg ha−1, and a density of 75–90,000 plants ha−1. The different input levels of maize crop management systems can modify an adaptive capacity to ecological conditions and the resilience of agro-ecosystems. The optimalization of agrotechnical elements reduces the harmful climatic effects. The yields of maize varied between 2–11 t ha−1 in extensive and 10–15 t ha−1 in intensive crop management systems, respectively.
Most agronomic soils contain large reserves of total phosphorus [P], but the fixation and precipitation of P cause P deficiency, and in turn, restrict the growth of crops severely. Phosphorus replenishment, especially in sustainable production systems, remains a major challenge as it is mainly fertilizer-dependent. Though the use of chemical P fertilizers is obviously the best means to circumvent P deficiency in different agro-ecosystems, their use is always limited due to its spiralling cost. A greater interest has, therefore, been generated to find an alternative yet inexpensive technology that could provide sufficient P to plants while reducing the dependence on expensive chemical P fertilizers. Among the heterogeneous and naturally abundant microbes inhabiting the rhizosphere, the phosphate solubilizing microorganisms (PSM) including bacteria have provided an alternative biotechnological solution in sustainable agriculture to meet the P demands of plants. These organisms in addition to providing P to plants also facilitate plant growth by other mechanisms. Despite their different ecological niches and multiple functional properties, P-solubilizing bacteria have yet to fulfil their promise as commercial bio-inoculants. Current developments in our understanding of the functional diversity, rhizosphere colonizing ability, mode of actions and judicious application are likely to facilitate their use as reliable components in the management of sustainable agricultural systems.
The interactions of ecological conditions, genotypes and agrotechnical elements determine the yield quantity, quality and stability in cereal (wheat, maize) production. The applied input- level can modify the adaptive capacity of crop models to ecological conditions. The effects of agrotechnical elements (crop rotation, fertilization, irrigation, crop protection, plant density) were studied in the long-term experiment on chernozem soil. Our scientific results proved that the high yields and good yield-stability were obtained in the input-intensive crop models, so these models had better adaptive capacity, high yield and resilience. Maize had lower ecological adaptive ability than winter wheat. The optimalization of agrotechnical elements reduces the harmful climatic effects so we can increase the yield and yield stability of cereals agro-ecosystems. The yields of wheat varied between 2 and 7 t ha−1 in extensive and 8 and 10 t ha-1 in intensive crop models and the yields of maize ranged between 2 and 11 t ha−1 and 10 and 15 t ha−1, respectively.
The present paper evaluates the results of field experiments conducted during two consecutive growth seasons (2008–2009) to assess the environmental impact of cement dust pollution on foliar physiology (pigments), growth performance and yield of three commonly cultivated vegetable crops, tomato (Lycopersicon esculentum), radish (Raphanus sativus) and knol-khol (Brassica oleracea var. gongyloides) in Kashmir Himalayan valley, India. Two experimental sites (S1, S2) were selected in the vicinity of the cement factory at Khrew, Pulwama (Kashmir) at a distance of 0.5 km (S1) and 2 km (S2) and compared with a dust free control site (S3) located at about 6 km from the factory in a crosswind direction. The data revealed that cement dust had an adverse effect on morphological and biochemical characteristics of the crops. Differential level of crop sensitivity to cement dust was markedly evident. Knol-khol (Brassica oleracea var. gongyloides) reflected a higher degree of tolerance to particulate emissions as compared to tomato (Lycopersicon esculentum) and radish (Raphanus sativus). Photosynthetic pigment analysis showed adverse impact on chlorophyll-a, while chlorophyll-b marginally decreased in the leaves of tomato plants at S1; the effect being non-significant for the other test crops. Carotenoids also exhibited a remarkable reduction due to cement dust impact. The yield of tomato recorded severe losses (12.28–23.95%) as compared to radish (7.46–21.4%), while the effect was non-significant in knol-khol. Other growth and yield related attributes also followed a similar trend; tomato and radish showing remarkable effects in response to cement dust and knol-khol showed the least effect. The soil characteristics indicated significant reduction in available P. Except available N, other variables (pH, conductivity, available K, exchangeable Ca and Mg) recorded higher values in the polluted soils as compared to control. The need for installation of appropriate devices in cement manufacturing factories to combat the emission of dust in ambient environment together with environmental monitoring of agro-ecosystems is stressed.
simulated nitrate leaching in vegetable culture. In: Horst W. J. et al. (eds) Plant nutrition. Food security and sustainability of agro-ecosystems through basic and applied research. Developments in plant and soil sciences. Kluwer, 936–937 pp
