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Crop rotation is one of the oldest and most effective methods of restoring soil fertility, which declines when the same plant is grown repeatedly. One of the reasons for a reduction in fertility is the accumulation of pathogenic and unfavorable microbiota. The modern crop rotation schemes (a set of plant species and their order in the crop rotation) are highly effective but are designed without considering soil microbiota dynamics. The main goal of this study was to perform a short-term experiment with multiple plant combinations to access the microbiological effects of crop rotation. It could be useful for the design of long-term crop rotation schemes that take the microbiological effects of the crop rotation into account. For the analysis, five plants (legumes: vetch, clover, and cereals: oats, wheat, and barley) were used. These five plants were separately grown in pots with soil. After the first phase of vegetation, the plants were removed from the soil and a new crop was planted. Soil samples from all 25 possible combinations of primary and secondary crops were investigated using v4-16S rDNA gene sequencing. It was shown that the short-term experiments (up to 40 days of growing) are effective enough to find microbial shifts in bulk soil from different plants. Both primary and secondary cultures are significant factors for the microbial composition of microbial soil communities. Changes are the most significant in the microbial communities of vetch soils, especially in the case of vetch monoculture. Growing clover also leads to changes in microbiota, especially according to beta-diversity. Data obtained can be used to develop new crop rotation schemes that take into account the microbiological effects of various crops. [ABSTRACT FROM AUTHOR]

Crop rotation is one of the oldest and most effective methods of restoring soil fertility, which declines when the same plant is grown repeatedly. One of the reasons for a reduction in fertility is the accumulation of pathogenic and unfavorable microbiota. The modern crop rotation schemes (a set of plant species and their order in the crop rotation) are highly effective but are designed without considering soil microbiota dynamics. The main goal of this study was to perform a short-term experiment with multiple plant combinations to access the microbiological effects of crop rotation. It could be useful for the design of long-term crop rotation schemes that take the microbiological effects of the crop rotation into account. For the analysis, five plants (legumes: vetch, clover, and cereals: oats, wheat, and barley) were used. These five plants were separately grown in pots with soil. After the first phase of vegetation, the plants were removed from the soil and a new crop was planted. Soil samples from all 25 possible combinations of primary and secondary crops were investigated using v4-16S rDNA gene sequencing. It was shown that the short-term experiments (up to 40 days of growing) are effective enough to find microbial shifts in bulk soil from different plants. Both primary and secondary cultures are significant factors for the microbial composition of microbial soil communities. Changes are the most significant in the microbial communities of vetch soils, especially in the case of vetch monoculture. Growing clover also leads to changes in microbiota, especially according to beta-diversity. Data obtained can be used to develop new crop rotation schemes that take into account the microbiological effects of various crops.

Highlights • Cropping systems and soil disturbance alter nematode trophic linkages, soil microbial community diversity and activity. • Nematode trophic linkages increased under crop rotation and zero tillage. • Plant-feeding nematodes decline in soils subjected to conventional tillage. • Crop rotation and zero tillage increase soil microbial richness and evenness. • Zero tillage increases soil microbial activity. Abstract During a four-year cropping cycle, the effects of cropping sequence (wheat-medic rotation and wheat monocropping) and contrasting degrees of soil disturbance (conventional tillage and zero tillage) on nematode functional guilds and soil microbial diversity indices and enzymatic activities were quantified. Extracted and identified nematode taxa were sorted into functional guilds and assigned to a colonizer-persister (cp) scale. Soil microbial species richness and abundance were measured using the Shannon-Weaver and Evenness diversity indices, respectively, while microbial enzymatic activities (ß-glucosidase, phosphatase, urease) were assayed to evaluate ecosystem functioning over time. Crop rotation and zero tillage practices increased nematode trophic linkages, whereas plant-feeding nematodes declined over time in soils subjected to conventional tillage practices. Zero tillage practices and crop rotation over time were found to increase soil microbial richness and evenness. Carbon, phosphorous and nitrogen mineralization rates were independently influenced based on cropping sequence, but were found to have increased (p < 0.05) over time under zero tillage practices. Quantitative analyses of integrated biological indicators under various agricultural management practices will assist in our understanding of possible practices to ensure healthier soils with the ability to support sustainable crop production. [ABSTRACT FROM AUTHOR]

Factors that determinated phytosanitarian chernozems worsening was examined in the space between Prut and Nistru in the global phenomenon of agricultural soil exhaustion. It was established anthropological and natural origin (pedofunctional) phenomenon of studied exhaustion chernozems exhaustion. The main cause of cernozems exhaustion is to reduce the dominant role of the training and accumulation of humus. Through this prism of ideas, soil exhaustion and phytosanitarian worsening is inherent to agricultural system currently practiced. The impact mitigating of this process involves the bioenergy resources sustainable management involved in anthropogenic pedogenesis.

In case of seismic design the deformability of the soil should be considered, which can be performed in several ways. Most of the methods do not take into account the finite dimensions of the soil, which results significantly different behavior than the spring-dashpot systems. For an infinite medium, which is used in many cases, there are no eigenmodes, however in practical applications the soft soil is always bounded by rocks. For these cases the soil has eigenmodes and the resonance may influence considerably the response of the system. This question was investigated numerically by FE calculations, and it was found that in certain cases the resonance, which is neglected in the common design process, may significantly enhance the earthquake loads. In this paper this phenomenon is investigated and the parameter range is defined when this effect must be taken into account. [ABSTRACT FROM AUTHOR]

Abstract: This article evaluates the proposition that farmers in dryland West Africa will be compelled by midcentury to shift household resources from crop to livestock production due to changing climate conditions. The article investigates the prospects for such a livelihood transition in the semiarid part of eastern Senegal, where downscaled statistical models indicate temperature increases of at least 2°, that will have substantially negative impacts on crop yields. Based on survey of 448 households and focus groups conducted across an eco‐climatological transect, the article presents evidence that this livelihood transition is already underway in many households but is increasingly out of reach for others. It uses statistical and qualitative analysis to argue that the most vulnerable households—crop‐dependent smallholders in the geographic area where the livelihood shift is most needed—are the least prepared for it. The article shows that land degradation is both an additional cause of the transition and an obstacle to it. Soil exhaustion, made worse by the lack of opportunities to procure chemical fertilizer, is compelling many to seek to increase their livestock holdings. This strategy is constrained by rangeland degradation, which, made worse by expanding agriculture, reduces the viability of the transition for all but the wealthiest households. Households rely on migration to compensate for shortfalls in production, but this option is becoming closed off to those households who do not already have a member abroad. This is shown to raise the vulnerability of households who rely on a degraded resource base for their livelihoods. [ABSTRACT FROM AUTHOR]

Vertical ground motion significantly affects the seismic response of engineering structures, particularly nuclear power plants and dams. However, most ground motion predictions or site response analyses focus on horizontal ground motion. As a result, knowledge of the characteristics of vertical ground motions is inadequate. In this study, a benchmark approach for equivalent linear vertical site response analyses is developed, with focus on the modeling of soil nonlinearity. The modeled soil exhibits different nonlinear behavior in the vertical direction depending on the saturation condition (i.e., above or below the groundwater table). Moreover, the vertical nonlinearity is different from that observed in the horizontal direction. The vertical ground responses predicted by the proposed approach are generally consistent with downhole measurements associated with different geological conditions, groundwater tables, and shaking intensities. [ABSTRACT FROM AUTHOR]

Background and aim: The long-term effect of elevated CO (eCO) on P biogeochemistry in farming systems is largely unknown. This study compared the effects of eCO on P fractions in three contrasting soils after growing crops for seven years. Methods: An experiment of free-air-CO-enrichment (FACE) was conducted with a rotation of wheat, field pea and canola grown in intact cores of Chromosol, Vertosol and Calcarosol under ambient CO (aCO) (390 ± 10 ppm) or eCO (550 ± 30 ppm). Crop P removal, soil P fractions and biochemical properties were determined. Results: Elevated CO resulted in extra 134, 91 and 93 mg P core removed as grains, compared to aCO, for Chromosol, Vertosol and Calcarosol, respectively. It decreased the concentration of NaHCO-extractable inorganic P (by 17-36%), and decreased NaOH-extractable inorganic P by 24% in Chromosol, and 77% in Vertosol but did not affect it in Calcarosol. Elevated CO also decreased NaOH-extractable organic P by 20, 12 and 7 mg kg in the three soils, respectively. Furthermore, eCO decreased soil organic carbon (by 8.2%) and increased microbial biomass carbon and respiration in Chromosol but not in other two soils. Conclusion: Long-term eCO favoured microbial mineralization of organic P in Chromosol and chemical mobilization of non-labile inorganic P in all three soils. [ABSTRACT FROM AUTHOR]

Soil exhaustion and nutrient depletion are major constraints to pineapple farming in Uganda. This study explored potential for using on-farm waste from pineapple farming to conserve soil fertility and enhance agricultural productivity. Data collection was done using key informant interviews, focus group discussions, and a semi structured survey questionnaire administered to 109 randomly selected pineapple farmers and processors. The data was analyzed in SPSS to generate descriptive statistics for selected variables followed by cross tabulation to explore linkages between the variables. Results indicate that farmers engaged in pineapple farming, have diverse socioeconomic backgrounds but activities engaged in are not significantly associated with socioeconomic variables examined except farming experience and gender. The major challenges faced by the farmers included soil exhaustion, lack of appropriate technologies, inappropriate pineapple waste management and decline in yield. It was noted that strategies used by farmers employing use of on-farm waste have not yielded significant contribution and as such farmers resort to use of off-farm manure which is expensive and increasingly hard to secure. It was recommended that a sustainable technology harnessing the abundant but underutilized on-farm biomass waste be developed to produce a highly nutrient-rich soil conditioner to enhance pineapple yield and as such empower the farmers. [ABSTRACT FROM AUTHOR]

This paper critically examines the soil exhaustion and societal collapse hypothesis both theoretically and empirically. The persistence of civilizations, especially in the Mediterranean, despite intensive and presumably erosive arable farming creates what is described here as the archaeology soil erosion paradox. This paper examines the data used to estimate past erosion and weathering rates before presenting case studies that engage with the theoretical arguments. Study 1 shows 5000 years of high slope erosion rates with both soil use and agriculture continuously maintained in the catchment. Study 2 shows how ancient agricultural terraces were constructed as part of an integrated agricultural system that fed the ancient city of Stymphalos-now abandoned. Study 3 presents a recent example of how after the removal of terraces high soil erosion rates result during intense rainstorms but that arable agriculture can still be maintained while external costs are borne by other parties. What these case studies have in common is the creation of soil, and increased weathering rates while productivity is maintained due to a combination of soft bedrock and/or agricultural terraces. In societal terms this may not be sustainable but it does not necessarily lead to land abandonment or societal collapse. [ABSTRACT FROM AUTHOR]

Questions What processes govern the long-term recovery of tropical secondary forests? Specifically, how are seedling species density, stem density and functional groups in older regenerating forests affected by existing trees, the regeneration environment and distance to seed sources? Location Central Catchment Nature Reserve, Singapore. Methods We investigated three primary forest plots and nine 60-yr-old secondary forest plots varying in their degree of recovery. We analysed seedling parameters as a function of the abiotic and biotic regeneration environment as well as distance to primary and mature secondary forests. Results The secondary forest plots had functional composition distinct from, and Chao-estimated species richness and stem density lower than the primary forest plots. Seedling communities were most strongly associated with the mature tree communities within each plot; associations with other intra-plot variables and distance to potential seed sources were lower but still highly significant. Overall, aside from the mature tree community, the most significant predictors of seedling species composition were fern cover, VPD, soil Al, available P and C:N ratio. Primary forest species were associated with low light environments, low macronutrients and low Al saturation. Secondary forest species were associated with high P, low soil pH and low total exchangeable bases. Long-lived pioneers differed from short-lived pioneers in their association with high soil C:N ratio, low Al saturation, low P and tolerance of a wider light range. Overall, improved seedling recruitment was associated with decreasing fern cover, thinner layer of leaf litter and higher light. At the landscape level, species density was inversely related to distance to potential seed sources. Conclusions Our findings suggest that historical soil degradation and subsequent feedback processes among the adult trees, seedling communities and the regeneration environment strongly affect forest succession. Nutrient-efficient and Al-tolerant pioneers, such as the fern Dicranopteris linearis, were probably initial colonizers. Chance dispersal and recovery of the regeneration environment subsequently affected the establishment of long-lived or short-lived pioneers. Persistence of D. linearis and long-lived pioneers slowed forest recovery, while short-lived pioneers improved nutrient recovery and ameliorated the above-ground conditions to facilitate subsequent succession, provided that seeds of primary forest species were present. [ABSTRACT FROM AUTHOR]

Long-term archaeological data gathering in the southern Netherlands may deliver an unprecedented regional comparison that could be exemplary for the Pleistocene sand areas of the Northwest European Plain. On a micro-scale level, it has become clear that Bronze Age (2000–800 BC) and Iron Age (800–12 BC) farmers intensively used the landscape, resulting in a relatively dense distribution pattern of settlements all over the ridges and planes of the cover sand landscape. However, this agricultural use of the landscape—related to the “celtic field” system—led to a process of soil degradation by increased acidification during which Umbric Podzols gradually transformed into Carbic Podzols that could no longer be used as farmland. According to established “models,” this process of “secondary podzolization” particularly affected those sections of the landscape that were dominated by dry sandy soils with a low loam content (loam = clay and silt, between c. 10% and 20%). In the Late Iron Age (250–12 BC), the changing soil conditions resulted in a dramatic shift in the habitation pattern that clearly manifests itself in the Roman period (12 BC–410 AD); on the local scale, the habitation moved from the degenerated soils to nearby areas with better soil conditions (higher loam content), which became more densely inhabited now than in the Bronze Age/Early Iron Age (2000–500 BC). The introduction of new land management (in the later Iron Age, and also by Romans) could also have been important for soil degradation. The areas where the Roman period settlements concentrated became also the areas where we can find the early medieval habitation (447–751 AD) and where the Plaggic Anthrosols started to develop in the late medieval period (1270–1500 AD). This paper is based on the analysis of soil properties. Measured loam values of soil samples ( n = 181) in Veldhoven, southern Netherlands, are in agreement with the described model that the plaggen cover is located on soils containing high combined silt and clay content (> 25%) and that Carbic Podzols with no plaggen cover have low combined silt and clay content (< 15%). Local spatial as well as vertical variations in loam content of sand layers have shown to occur, warning against single parameter research. Other potential causes for the deviation of the model are as follows: (a) impact of fluctuating groundwater levels; (b) impact of different hydrological properties in the shallow subsurface, depending on the grain size and transmissivity of the sediments; (c) organic matter content; (d) land management; and (e) climate change. [ABSTRACT FROM AUTHOR]

The article discusses a study which compared the degree of vulnerability from the alteration or loss of carbon (C) in soils at sites where the land cover was converted from forest to pasture in 4 municipalities in Sao Paolo, Brazil. Topics discussed include soil organic matter (SOM) as one of the 3 core soil attributes that underly the quality of soil ecosystems services and how land cover change may be main anthropogenic component driving local environmental fate.

This study aimed to evaluate the effect of management strategies of irrigation with saline water on growth and yield of cowpea and sunflower in a crop rotation. The experiment was conducted in randomized blocks with thirteen treatments and five replications. The treatments consisted of: T1 (control), T2, T3 and T4 using water of 0.5 (A1), 2.2 (A2), 3.6 (A3) and 5.0 (A4) dS m-1, respectively, during the entire crop cycle; T5, T6 and T7, use of A2, A3 and A4 water, respectively, only in the flowering and fructification stage of the crop cycle; using different water in a cyclic way, six irrigations with A1 followed by six irrigations with A2 (T8), A3 (T9) and A4, (T10), respectively; T11, T12 and T13, using water A2, A3 and A4, respectively, starting at 11 days after planting (DAP) and continuing until the end of the crop cycle. These treatments were employed in the first crop (cowpea), during the dry season, and the same plots were used for the cultivation of sunflower as succeeding crop during rainy season. The strategies of use of saline water in the salt tolerant growth stage (treatments T5, T6 and T7) or cyclically (treatments T8, T9 and T10) reduced the amount of good quality water used in the production of cowpea by 34 and 47%, respectively, without negative impacts on crop yield, and did not show the residual effects of salinity on sunflower as a succeeding crop. Thus, these strategies appear promising to be employed in areas with water salinity problems in the semiarid region of Brazil. [ABSTRACT FROM AUTHOR]

[Objective] The aim was to analyze effects of jujube planting years on changes of soil nutrient elements and explore the causes of orchard degradation by researching variation characteristics of soil nutrient contents in orchards with different planting years, providing theoretical support for the soil degradation of jujube orchards. [Method] Soil samples were collected in depth at 0-20 and 20-40 cm from the sites in or out of tree canopy scope in jujube orchards with 3, 5 and 7 planning-years, to analyze contents of available N, P and K, organic matter, total N, salts, and trace elements, as well as changes of nutritional elements. [Result] Available boron, copper, iron, manganese, zinc and available potassium in soils of jujube orchards with 3, 5 and 7 years planting history reduced as planting year increased, which coincided with that in the soil of 20-40 cm. [Conclusion] Because trace elements are never applied in southern Xinjiang, available B, Cu, Fe, Mn, and Zn and available K would be consumed by tree root growth. Due to root distribution differences and ploughing effects in fields, the contents of nutrients tend to be volatile in or out of tree canopy scope. Tree root in deeper soils absorbs more nutrients, and soil nutrients would decrease dramatically if additional chemical fertilizers are not provided, leading to soil degradation. [ABSTRACT FROM AUTHOR]

This paper presents the application of blurred or diffuse logic, to identify the types of soils most affected in an agro-system, by the Central Mechanism of Soil's Overuse Syndrome, taking as a case study: the presence of the syndrome symptoms and the degree in which they affect the agro-system: Finca "La Esperanza", in the province of Camagüey, where the Big6 model was used. Besides, twelve types of soils are identified, which are the most affected by the aforementioned syndrome and symptoms with far-reaching effect on these soils. The rigorous execution of the different steps of the applied blurred method admitted having selected the most affected soils by the twelve signs of the Central Mechanism of Soil's Overuse Syndrome. [ABSTRACT FROM AUTHOR]

Most organic farmers in South Korea use a synthetic plastic film mulch to control weeds, plus high amounts of organic nutrients sourced from outside the cropping area, due to a lack of information on crop rotations using legume or deep-rooting cover crops. We have evaluated the effects of cover crop rotation on soil and plant nutrition during red pepper (Capsicum annuum L.) production from 2002 to 2005. The four treatments applied were: (i) a conventional farming (CF) system without cover crop rotation, or (ii) three organic farming (OF) systems, which either rotated the annual production of red peppers with hairy vetch (OF+HV), or rye (OF+R) from 2002 to 2004, or had an alternating cultivation of rye in 2002 and in 2004 with hairy vetch in 2003 (OF+R-HV). The OF+HR system increased the below-ground biomass [39 MT ha-1, fresh weight (FW)] of the rye cover crop, but the above-ground biomass of the cover crop (22 MT ha-1 FW) was similar to those in the OF+HV and OF+R-HV systems. All OF systems, especially OF+HV, increased the soil pH, as well as P, K, Ca, and Mg concentrations to a soil depth of 0 - 20 cm in 2003, and pH, total-N, and K concentrations in 2005. Soil pH. electrical conductivity, and macro-nutrient concentrations decreased from 20 - 100 cm soil depth. All three OF systems reduced the bulk density of the soil and increased soil porosity compared to the CF system. Higher mineral nutrient concentrations in plants grown in the CF system compared to the three OF systems occurred only for Mg in 2003. The CF system increased marketable fruit yields, but did not increase the annual gross income. The highest crop value was observed in the OF+HV system. There was a net loss of N (-9 kg ha-1) in the OF+HV system in all 3 years, while the OF+R system had the highest positive balance level of N (54 kg ha-1). Therefore, the leguminous cover crop (hairy vetch) was useful as a green manure to increase annual gross incomes, increase N-use efficiency, and reduce soil N losses. [ABSTRACT FROM AUTHOR]

Highlights: [•] Farming systems had no influence on tuber K, Ca, DM and starch concentrations. [•] Farming systems affected tuber fresh yield, N, nitrate, Mg and P concentrations. [•] The yield increase had a non-significant effect on some mineral elements in tubers. [•] Negative control (N0) and Nhigh were the most soil exhausting systems. [ABSTRACT FROM AUTHOR]

The analysis of usage conflict was carried out by means of the physical attitudes of the soils for the main crops of economical importance in the UBPC "La Julia" (potato, sweet potato, beans, tomato, corn) in order to avoid over operation and also strengthen the management of the agricultural system. The evaluation of the soils was based on a FAO, scheme leaned on ALES software. It was supported on models of knowledgements created using relevant information developed by spacial data. As a result of the evaluation, it was evident that the main qualities that limit the productivity of the soils are: rooting conditions, airing, and acidity. Besides, it was discovered that the 13,6% and 86,35% of all the evaluated grounds face medium and high conflict, respectively. If mean that there is a need of making a territorial order to the analyzed scenary. [ABSTRACT FROM AUTHOR]

In this paper, we report on a field experiment being carried out in a Typic Eutrorthox. The experiment was initiated in the 1997-98 agricultural season as a randomized block design with four treatments (0, 5, 10, and 20 t ha) of sewage sludge and five replicates. Compound soil samples were obtained from 20 subsamples collected at depths of 0-0.1 and 0.1-0.2 m. Cu, Fe, Mn, and Zn concentrations were extracted with DTPA pH 7.3; 0.1 mol L HCl, Mehlich-I, Mehlich-III, and 0.01 mol L CaCl. Metal concentrations were determined via atomic absorption spectrometry. Diagnostic leaves and the whole above-ground portion of plants were collected to determine Cu, Fe, Mn, and Zn concentrations extracted by nitric-perchloric digestion and later determined via atomic absorption spectrometry. Sewage sludge application caused increases in the concentrations of soil Cu, Fe, and Mn in samples taken from the 0-0.1 m depth evaluated by the extractants Mehlich-I, Mehlich-III, 0.01 mol L HCl and DTPA pH 7.3. None of the extractants provided efficient estimates of changes in Mn concentrations. The acid extractants extracted more Cu, Fe, Mn, and Zn than the saline and chelating solutions. The highest concentrations of Cu, Fe, and Zn were obtained with Mehlich-III, while the highest concentrations of Mn were obtained with HCl. We did not observe a correlation between the extractants and the concentrations of elements in the diagnostic leaves nor in the tissues of the whole maize plant ( Zea mays L.). [ABSTRACT FROM AUTHOR]

Faba bean (Vicia faba L.) is a major food source and fodder legume, popularly known for its high content of seed-protein. Its role is critical in crop rotation, and for fixing nitrogen effectively. Polymorphic simple sequence repeat markers from transcript sequences (cDNA; simple sequence repeat [SSR]) were developed for faba bean (Vicia faba). We found that 1,729 SSR loci from 81,333 individual sequence reads and 240 primer pairs were designed and synthesized. In total, 55 primer pairs were found to be polymorphic and scorable consistently when screened in 32 accessions. The number of alleles ranged from 2 to 15, frequency of major alleles per locus varied from 0.17 to 0.91, the genotypes number ranged from 2 to 17, observed and expected heterozycosity values ranged from 0.00 to 0.44 and 0.17 to 0.89 and overall PIC values ranged from 0.16 to 0.88 respectively. These markers will be a useful tool for assessing the genetic diversity, understanding the population structure, and breeding patterns of faba bean. [ABSTRACT FROM AUTHOR]

Narrow-leaved lupin (Lupinus angustifolius) is being assessed as a potential pulse crop for western Canada. However, root rot caused byFusariumspp. is a potentially important disease of lupin in the region. The aim of this study was to identify theFusariumspp. that aggressively attack lupin in central Alberta.Fusariumisolates were recovered from diseased lupin plants in 2005 and 2006.Fusarium avenaceumwas the most frequently recovered species, followed byF.oxysporum, F.solani, andF.acuminatum. Inoculation of lupin withF. avenaceumproduced severe root rot symptoms in a greenhouse assay, although there was a wide range in aggressiveness among isolates within this species. Although lupin roots were often colonized by otherFusariumspecies in addition toF.avenaceum, these other species were shown to be non-pathogenic or only weakly pathogenic. Co-inoculation studies indicated that the otherFusariumspecies that are associated with lupin roots do not contribute to a disease complex, so we conclude thatF.avenaceumis the dominant pathogen responsible for root rot on lupin in central Alberta. The host range ofF.avenaceumisolates from lupin included a wide range of pulse and oilseed crops grown in the region, so crop rotation is unlikely to have an important impact on management of this potentially destructive pathogen. [ABSTRACT FROM AUTHOR]

The effects of a two-crop rotation and herbicide application on the reduction weed infestation of maize (Zea mays L.) were studied in this trial. The studies were carried out in the experimental field of the Maize Research Institute, Zemun Polje in the period 2009-2011. The trial encompassed two factors: the application of crop rotations with the maize continuous cropping and the two-crop rotation (maize-wheat rotation) variants, as well as the application of herbicides (isoxaflutole+acetochlor) at the three levels: recommended rate (105 g a.i. + 1536 g a.i.), half the recommended rate of herbicides (52.5 g a.i. + 768 g a.i.) and control, without herbicide use. Herbicides were applied after sowing but prior to maize emergence. During the three years of investigation the hybrid ZP 677 was sown in the continuous cropping variant and the two-crop rotation. The number of weed species, as well as, the number of weed plants per species, and their fresh biomass were determined. In the initial year of investigation (2009) the values obtained in the continuous cropping and the two-crop rotation were uniform in dependence on the level of applied herbicides. However, after the first maize-wheat rotation, changes occurred in 2011, as a result of crop rotation. The number of weed species in the two-crop rotation variant was lower, from three to five, than in variant with the continuous cropping. Furthermore, the number of weed plants per species and fresh biomass of weeds were lower in the two-crop rotation variant than in maize continuous crop especially with application of the recommended rate of herbicides. [ABSTRACT FROM AUTHOR]

The article analyzes the environmental history of the arid ecosystems of lower southern California, Mexico. Proper cultivation of the land was introduced by Jesuit missionaries and ranchers in the 18th century to the indigenous populations, sustains the author. The sustainable use of natural resources and the use of Mediterranean and Middle Eastern oases culture by the Indian population is discussed. The consequences of the perforation of wells for extension, soil exhaustion and the overuse of land and water between 1950 and 1990 are addressed by the author.

This study presents soil system budgets of N, P and K in six contrasting cropping systems during 10 years of a long-term experiment in southeast Norway. The experiment included systems with arable cash-cropping and with mixed arable-dairy cropping (cash- and fodder crops), with organic and conventional management represented in both groups. All major nutrient inputs and outputs were measured or estimated. State of the art conventional cash-cropping appeared to be balanced in terms of N, whereas conventional mixed cropping had an N surplus. By contrast, less up to date conventional arable cash-cropping and all the organic systems showed indications of soil organic N depletion (negative N budgets). All the organic systems showed that mining of the soil P and K content occurs, whereas the conventional systems all had P and K surpluses. The results corresponded well with measured differences between systems in terms of ignition loss, P-AL, K-AL and K-HNO3 measured in 2009. This study shows that a fertile soil may be exposed to substantial mining of N, P and K over many years before it is detectable by traditional analyses, and that field nutrient budgeting is a feasible, but data-demanding, approach to detect such misbalances at an early stage. [ABSTRACT FROM AUTHOR]

A long term trial comparing ecological (ECO) and integrated (INT) farming systems was carried out in western Slovakia from 1990 to 2009. The location has a continental climate, with average temperatures of 19,7 °C in July and -- 1,7 °C in January and an average annual precipitation of 561 mm, the soil type is a Haplic luvisol. The ECO and INT systems were composed of a six stage crop rotation. Subplots were fertilised and unfertilised treatments. 25 g samples of w. wheat was placed into a 250 mL glass Erlenmayer flask and then 100 mL of 84+16 acetonitrile water were added. After stired extract was filtered and clean up by immunoaffinity column MycoSepTM 226 for ZON and 227 for DON. Purified extract was evaporate to dryness using RVO 400 and redisloved in 0,5 mL mobile phase. The concentration of deoxynivalenol (DON) and Zearalenone (ZON) was detected in the w. wheat grain samples by using of HPLC WATERS BREEZE equipped with binary pump WATERS 1525, RHEODYNE injector and UV detector WATERS 2487 was used with a stainless steel reverse phase 150x3,9 mm, 4 µm spherical particle C18 Nova-Pak column. UV detector set to 218 nm for DON and 238 nm for ZON. Mobile phase were mix of of A: water, B: acetonitrile with using gradient. In ECO system, the concentration of DON was lower by 46% (average 192,4 µg.kg-1) compared with INT system (average 361,6 µg.kg-1). Fertilisation treatments enhanced the level of DON in both systems. Within INT system also pre-crop effect on DON was revealed, peas as pre-crop significantly enhance the concentration of DON. The effects of farming system and fertilisation were not significant for ZON, but level of ZON was influenced by weather conditions. Drier and warmer weather supported the production of ZON, more humid and warm weather enhanced the level of DON. [ABSTRACT FROM AUTHOR]

A better understanding of the P cycle is necessary to provide insights into management strategies that could enhance P bioavailability for crops. Our objectives were to evaluate the effects of continuous P fertilization on (i) the P budget, (ii) soil-retractable P (Pe) dynamics. and (iii) the relationship between these variables. Two crop rotations during a 6-yr period were analyzed in seven on-farm experiments: corn (Zea mays L.)-double cropped wheat ( Triticum aestivum)/soybean [Glycine max (L.) Merr.] (C-W/S), and corn-soybean-double cropped wheat/soybean (C-S-W/S). Calculations of net P input considered only P removal (output) and fertilization (input). Initial soil-test P was l3.4mg P kg-1 (average for the four sites) for the C-W/S rotation and 37.9mg p kg-1 for the C-S.W/S rotation (average for the three sites). Treatment combinations were two annual rates: unfertilized and grain P removal estimation + 10% (overage 34 kg p ha-1 yr-1). Not applying P to soils testing 45 to 68 mg kg-1 of initial Pe resultrd in a steep Pe decline (slope 0.2 mg kg-1 per unit of negative P budget). Nevertheless, soils with <25 mgkg-1 of initial Pe levels resulted in a very small and gradual decline (slope 0.02 mg kg-1). Use of current P rates applied by local farmers probably results in a small soil-test P buildup with time. The P required to increase Pe by 1 mg P kg-1 was 11 and 8 kg P ha-1 yr-1 for the C-W/S and C-S-W/S rotations, respectively. [ABSTRACT FROM AUTHOR]

Few experiments have directly compared the long-term effects of moldboard, chisel, and no-till tillage practices on N2O emissions from the predominant crop rotation systems in the midwestern United States. This study was conducted from 2004 to 2006 on a tillage and rotation experiment initiated in 1975 on a Chalmers silty clay loam (a Typic Endoaquoll) in west-central Indiana. Our objectives were to assess (i) long-term tillage (chisel [CP], moldboard plow [MP], and no-till [NT]), rotation (Continuous corn [Zea mays L.] and corn-soybean [Glycine max (L.) Merr.]), and rotation x tillage interaction effects on soil N2O emission, and (ii) how soil N2O emission is related to environmental factors during corn production under identical N fertilizer management. Seasonal N2O emissions were measured at intervals ranging from a few days to biweekly for up to 14 sampling dates in each growing season for corn. Nitrous oxide emissions during the growing season were significantly affected by tillage and rotation but not their interaction; however, 50% of total emissions occurred shortly after N application regardless of tillage or rotation practices. Seasonal cumulative emissions were significantly lower under NT but not statistically different for CP and MP. Overall, emissions under NT were about 40% lower relative to MP and 57% lower relative to CP. Rotation corn lowered N2O emissions by 20% relative to continuous corn. Higher N2O emission under MP and CP appeared to be driven by soil organic C decomposition associated with higher levels of soil-residue mixing and higher soil temperatures. [ABSTRACT FROM AUTHOR]

The Long-term Fertilisation Experiment was established in 1986 near Vienna with a three-year crop rotation (sugar beet-winter wheat-winter barley). The most distinct yield effects of organic fertilisation occurred with missing and low mineral N fertilisation. In the treatment without mineral N fertilisation, significantly higher sugar yields (+2.52 t ha-1) were obtained with the application of farmyard manure (FYM) compared to the control. Without mineral N fertilisation significant winter wheat increases through after effects of FYM and slurry application (+0.74 and 0.55 t ha-1) appeared. N surpluses in the variant with incorporating crop residues could be reduced by the omission of mineral N fertilisation with the incorporation of the straw. The highest mean P balances occurred with the application of FYM and slurry, the highest K surpluses were detected in the treatments where crop residues (especially K rich sugar beet leaves) remained on the field. The N, P and K balances correlated significantly (p < 0.05) with the Nt, PCAL and KCAL contents in the soil, respectively. On average of 21 years the utilisation of the applied FYM N amounted 42% and that of slurry N 39%. A higher N utilisation was found using mineral N (between 62% and 77%). [ABSTRACT FROM AUTHOR]

In this trial the effect of mineral and organic fertilization was investigated on the biomass production (grain and straw), N balance, N uptake of winter wheat and some indices of N utilization (N harvest index %, N use efficiency, agronomic efficiency, apparent recovery efficiency) as well as soil fertility in a long-term field experiment. The bifactorial cereal crop rotation (w. wheat, w. barley, maize) trial was set up in 1984 in Keszthely, Hungary, as a part of the international mineral and organic nitrogen fertilization trial network (IOSDV). The statistical significance of the experimental factors (increasing rates of N fertilizer and organic fertilization) was tested by analysis of regression and variance. As a result of the experimental treatments it can be concluded that the increasing rate of N fertilization as well as the additional organic fertilizers influenced the biomass production and N uptake of winter wheat or soil fertility. The Corg content of soil increased significantly with the incorporation of both farmyard manure and straw. Thus, straw as a byproduct should be recycled into the soil mainly if there is no animal husbandry in the farm to preserve the C balance. [ABSTRACT FROM AUTHOR]

The relationship between vegetation and precipitation has been studied extensively, but little is known about its mechanistic linkage to agro-ecosystem sustainability. In this study, we used 250 m MODIS NDVI 16-day composite data and precipitation data for the period 2001-2005 to evaluate the connection between vegetation and precipitation in the Jinghe River watershed of the central Loess Plateau, China. A principal component analysis (PCA) was employed to determine the primary feature of vegetation cover. The results indicated that the first two principal components (PC1 and PC2) explained around 89% of total NDVI variances. The spatial distribution of PC1 followed an increasing trend from northwest to southeast, a similar dynamics to the spatial pattern of NDVI, which was determined by the variation of mean annual precipitation in the Jinghe River watershed. Furthermore, PC2 was associated with the spring/summer modes of the annual cycle while their intra-annual variations were largely modified by the regular phonological cycle of the winter wheat-summer fallow cropping practices, a dominant farming practice in severely degraded regions of the Loess Plateau. Winter wheat-summer fallow practice was a dominant factor affecting the precipitation-vegetation relationship. A sharp decrease in vegetation cover after wheat harvesting during the rainy seasons from July to September may be a major cause of extensive soil erosion in this region. Our findings provide new insight into the relationship between vegetation and precipitation which is critical in the restoration of degraded ecosystems and developing appropriate crop rotation systems to achieve a certain amount of agricultural sustainability. [ABSTRACT FROM AUTHOR]

Soil tillage has been shown to affect long-term changes in soil organic carbon (SOC) content in a number of field experiments. This paper presents a simplified approach for including effects of tillage in models of soil C turnover in the tilled-soil layer. We used an existing soil organic matter (SOM) model (CN-SIM) with standard SOC data for a homogeneous tilled layer from four long-term field experiments with conventionally tilled (CT) and no-till (NT) treatments. The SOM model was tested on data from long-term (>10 years) field trials differing in climatic conditions, soil properties, residue management and crop rotations in Australia, Brazil, the USA and Switzerland. The C input for the treatments was estimated using data on crop rotation and residue management. The SOM model was applied for both CT and NT trials without recalibration, but incorporated a ‘tillage factor’ ( TF) to scale all decomposition and maintenance parameters in the model. An initial value of TF = 0.57 (parameter uncertainty, PU = 0.15) for NT (with TF set to 1.0 for CT) was used on the basis of a previous study with observations of soil CO2 respiration. The simulated and observed changes in SOC were then compared using slopes of linear regressions of SOC changes over time. Results showed that the SOM model captured observed changes in SOC content from differences in rotations, N application and crop residue management for conventional tillage. On the basis of SOC change data a mean TF of 0.48 (standard deviation, SD = 0.12) was estimated for NT. The results indicate that (i) the estimated uncertainty of tillage effects on SOC turnover may be smaller than previously thought and (ii) simple scaling of SOM model parameters may be sufficient to capture the effects of soil tillage on SOM turnover in the tilled layer. Scenario analyses showed that the average extra C input needed to compensate for soil tillage was 762 (SD = 351) kg C ha−1 year−1. Climatic conditions (temperature and precipitation) also affected how much extra C was needed, with substantially larger inputs being required for wetter and warmer climates. [ABSTRACT FROM AUTHOR]

Soil exhaustion is a major concern particularly in ferruginous soils of the tropics and restoration of soil quality through management of soil organic carbon (SOC) is one of the options to combat the situation. To understand the scope of different systems to sequester organic carbon in ferruginous soils (Typic Rhodustalfs), three representative systems, viz. agriculture (40 years), horticulture (20 years) and forestry (several centuries) were selected in a contiguous area under semi-arid tropical climate. The study indicated that the quasi-equilibrium value (QEV) of SOC decreased from 1.78 to 0.68% in the first 30 cm, when the soils are used for agriculture instead of retaining them as forest. A shift from agricultural to horticultural system over 20 years increased the QEV to 0.81% indicating accumulation of SOC. The highest threshold value of SOC is observed in forest system, followed by horticultural and the lowest in agricultural system. The present study indicates that horticultural system is a better option to enhance the SOC if forestry is not feasible in these ferruginous soils. [ABSTRACT FROM AUTHOR]

Weed species diversity may benefit from organic farming due to enhanced temporal diversification of crop species in a rotation and omission of herbicide applications. However, in intensively managed conventional systems, little evidence exists as to what extent diversified crop rotations contribute to higher weed species richness. Using an on-farm approach, the effect of crop rotation (organic, conventional diverse (CD) and conventional simple (CS) crop rotations) and weed control (with vs. without) on weed species richness, cover, community composition and crop biomass, was analysed in 24 winter wheat fields. Weed species with beneficial functions for invertebrates and birds were analysed separately. Weed species richness was higher in the organic crop rotation, but did not differ between CD and CS crop rotations. Weed control treatment reduced species richness in both conventional rotations, but not in the organic one. Redundancy analyses revealed that crop rotation intensity accounted for the largest part of the explained variation in weed species composition. Results from the study indicate that the maintenance of weed species richness and conservation of species with important ecological functions requires not only temporal diversification of crop species in the rotation, but also an adjustment of weed control strategies. [ABSTRACT FROM AUTHOR]

Abstract: Management of N is the key for sustainable and profitable wheat production in a low N soil. We report results of irrigated crop rotation experiment, conducted in the North West Frontier Province (NWFP), Pakistan, during 1999–2002 to evaluate effects of residue retention, fertilizer N application and mung bean (Vigna radiata) on crop and N yields of wheat and soil organic fertility in a mung bean–wheat sequence. Treatments were (a) crop residue retained (+residue) or (b) removed (−residue), (c) 120kgNha−1 applied to wheat, (d) 160kgNha−1 to maize or (e) no nitrogen applied. The cropping system was rotation of wheat with maize or wheat with mung bean. The experiment was laid out in a spit plot design. Postharvest incorporation of crop residues significantly (p <0.05) increased the grain and straw yields of wheat during both years. On average, crop residues incorporation increased the wheat grain yield by 1.31 times and straw yield by 1.39 times. The wheat crop also responded strongly to the previous legume (mung bean) in terms of enhanced grain yield by 2.09 times and straw yield by 2.16 times over the previous cereal (maize) treatment. Application of fertilizer N to previous maize exerted strong carry over effect on grain (1.32 times) and straw yield (1.38 times) of the following wheat. Application of N fertilizer to current wheat produced on average 1.59 times more grain and 1.77 times more straw yield over the 0Nkgha−1 treatment. The N uptake in wheat grain and straw was increased 1.31 and 1.64 times by residues treatment, 2.08 and 2.49 times by mung bean and 1.71 and 1.86 times by fertilizer N applied to wheat, respectively. The soil mineral N was increased 1.23 times by residues, 1.34 times by mung bean and 2.49 times by the application of fertilizer N to wheat. Similarly, the soil organic C was increased 1.04-fold by residues, 1.08 times by mung bean and 1.00 times by the application of fertilizer N. We concluded that retention of residues, application of fertilizer N and involvement of legumes in crop rotation greatly improves the N economy of the cropping system and enhances crop productivity in low N soils. [Copyright &y& Elsevier]

Soil organic matter (OM) content is a quality indicator, but is an inadequate indicator in the short-term because these changes take place slowly, so dissolved organic components have emerged as an alternative. In volcanic soil subjected to different crop rotations with distinct land use intensity, dissolved organic C and N (DOC and DON) were determined as well as their relationship with total C and N contents in the soil, considering the effects of crop rotation, fertilization level, and soil depth. In humid samples of Humic Haploxerands collected at four depths up to 40 cm, DOC and DON contents were determined by extraction with K2SO4 and filtered. Results indicated interaction between the studied factors, DOC fluctuated between 67.8 and 151.7 mg kg-1 with the highest value with intensive management in rotations that included corn (Zea mays L.) associated with a higher fertilization. DON fluctuated between 4.62 and 37.4 mg kg-1 with the highest value in non-intensive rotations that included prairie. With respect to total C, DOC reached 0.40% with intensive management and the lowest value in non-intensive management. DON showed values between 0.13 and 0.68% with respect to total N with intensive and non-intensive management, respectively. Tillage management affected DOC and DON contents depending on the fertilization level and the depth at which it was determined, and were also affected by the crop included in the rotation, thus making these parameters good indicators to evaluate the effects of agronomic management in the short-term. [ABSTRACT FROM AUTHOR]

The present study was aimed at characterizing the soil–water resource degradation in the rural areas of Gurgaon and Mewat districts, the two economically contrasting areas in policy zones-II and III of the National Capital Region (NCR), and assessing the impact of the study area’s local conditions on the type and extent of resource degradation. This involved generation of detailed spatial information on the land use, cropping pattern, farming practices, soils and surface/ground waters of Gurgaon and Mewat districts through actual resource surveys, standard laboratory methods and GIS/remote sensing techniques... [ABSTRACT FROM AUTHOR]

Abstract: Two management systems (conventional vs. organic) in a 3-years crop rotation (pea–durum wheat–tomato) were compared after 4 years in order to assess soil carbon (C) changes in a short-term period. Biochemical properties of soil, such as microbial biomass C and N (MBC and MBN), microbial respiration, N mineralization, dehydrogenase, chitinase, acid–phosphatase, arylsulfatase and β-glucosidase activities, were chosen as indicators of soil organic matter biochemical alteration. The main questions addressed in this study were (1) do soil biochemical properties discriminate between organic and conventional management systems in a short-term period? (2) Which biochemical indicator is more effective in predicting soil organic C accumulation in organically managed agricultural soils? A general increase of hydrolytic enzymes activities has been observed in soil under organic management. MBC, MBN and the MBC/TOC ratio (q mic) increased in organic soil under pea (100%, 50% and 100%, respectively) and durum wheat (55%, 28% and 42%, respectively), while the basal respiration per unit of microbial biomass () decreased (48% and 40% under pea and durum wheat, respectively). Moreover, the specific activity of β-glucosidase was significantly lower under organic management of pea and durum wheat and was positively correlated with , suggesting a lower maintenance energy requirement of the microbial community. Soil microbial biomass and enzymatic activities were successfully used to detect short-term changes in soil and, taking into account its role in soil functioning, β-glucosidase resulted the most suitable indicator to predict organic C accumulation in soil under organic management in a Mediterranean environment. [Copyright &y& Elsevier]

Abstract: Maintaining or increasing soil organic carbon (SOC) in agricultural lands is important for soil productivity, restoration and could potentially be a factor in reducing carbon emissions. In order to implement best practices for maintaining productivity and increasing SOC, there is a need for understanding how management changes may alter SOC levels. This applied study presents a methodology to assess and predict SOC levels to better understand effects modification to land management can have in semiarid central Spain. Results show extensification using longer-term pasture rotations (e.g. 5-year) could increase SOC levels and have an impact on soil restoration important in maintaining productivity. SOC increases brought about by new management may also have a role in contribution to national carbon emission reduction plans. [Copyright &y& Elsevier]