Effects Of Agricultural Practices Research Articles

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Effects of agricultural practices and fine-scale landscape factors on spiders and a pest insect in Japanese rice paddy ecosystems

We examined the effects of environmentally friendly (EF) farming and landscape factors on the abundances of major spider guilds and a rice pest, the small brown planthopper (SBPH), Laodelphax striatellus (Fallen), in a Japanese rice paddy ecosystem. The abundances of all spider guilds increased by EF farming, whereas different spider guilds showed contrasting responses to the size of the forest within 200 m of the fields. The abundances of ground spiders and horizontal web weavers increased with increasing forest area, unlike small ground spiders, whose abundance decreased. The abundances of SBPH nymphs and adults decreased by EF farming but responded differently to landscape: nymphs decreased with increasing forest area, but adults did not. Further analysis indicated a potential negative relationship between web-weaving spiders and SBPH nymphs. Our findings suggest that the size of the forest adjacent to fields is an important determinant of spider guild composition and pest abundance.

Structural Equation Model of Total Phosphorus Loads in the Red River of the North Basin, USA and Canada.

Attribution of the causes of trends in nutrient loading is often limited to correlation, qualitative reasoning, or references to the work of others. This paper represents efforts to improve causal attribution of water-quality changes. The Red River of the North basin provides a regional test case because of international interest in the reduction of total phosphorus loads and the availability of long-term total phosphorus data and ancillary geospatial data with the potential to explain changes in water quality over time. The objectives of the study are to investigate structural equation modeling methods for application to water-quality problems and to test causal hypotheses related to the drivers of total phosphorus loads over the period 1970 to 2012. Multiple working hypotheses that explain total phosphorus loads and methods for estimating missing ancillary data were developed, and water-quality related challenges to structural equation modeling (including skewed data and scaling issues) were addressed. The model indicates that increased precipitation in season 1 (November-February) or season 2 (March-June) would increase total phosphorus loads in the basin. The effect of agricultural practices on total phosphorus loads was significant, although the effect is about one-third of the effect of season 1 precipitation. The structural equation model representing loads at six sites in the basin shows that climate and agricultural practices explain almost 60% of the annual total phosphorus load in the Red River of the North basin. The modeling process and the unexplained variance highlight the need for better ancillary long-term data for causal assessments.

A Review Article : The Effect of Agricultural Practices on The Abundance and Biodiversity of Soil Fauna

A Review Article : The Effect of Agricultural Practices on The Abundance and Biodiversity of Soil Fauna

Crop residues exacerbate the negative effects of extreme flooding on soil quality

Extreme flood events are predicted to have a negative impact on soil quality. Currently, there is a lack of information about the effect of agricultural practices on soil functioning and microbial processes under these events. We hypothesized that the impact of flooding on soil quality will be exacerbated when crop residues are present in the soil as they will induce more extreme anaerobicity. A spring extreme flood event (10 °C, 9 weeks) was simulated in mesocosms containing an arable sandy-loam soil low in nutrients. The main treatments were (1) with and without flooding and (2) with and without maize residue addition (8 Mg ha−1). We monitored changes in soil chemical quality indicators (e.g. pH, salinity, Fe3+, P, C, NH4+, NO3− and organic N), greenhouse gas (GHG) emissions (CO2, CH4, N2O) and soil microbial community composition (PLFAs) during a prolonged flood period (9 weeks) and an 8-week “recovery” period after flooding. In comparison to the other treatments, flooding in the presence of crop residues resulted in a dramatic drop in soil redox potential. This was associated with the enhanced release of Fe and C into solution and an increase in CH4 emissions. In contrast, maize residues reduced potential nitrate losses and N2O emissions, possibly due to complete denitrification and microbial N immobilization. Both flooding and maize residues stimulated microbial growth and promoted a shift in microbial community composition. Following floodwater removal, most of the soil quality indicators returned to the levels of the control treatment within 5 weeks. After this short recovery phase, no major impact of flooding could be observed on plant growth (maize pot-grown). Overall, we conclude that both extreme flooding and management regime negatively impact upon a range of soil quality indicators (e.g. redox, GHG emissions); however, the soil showed high resilience and recovered quickly after floodwater removal. Further work is required to investigate the impact of repeated extreme flood events on soil quality and function over longer timescales.

Land use alters arbuscular mycorrhizal fungal communities and their potential role in carbon sequestration on the Tibetan Plateau

Loss of belowground biodiversity by land-use change can have a great impact on ecosystem functions, yet appropriate investigations remain rare in high-elevation Tibetan ecosystems. We compared arbuscular mycorrhizal (AM) fungal communities in arable soils with those in native forest and grassland in southeast Tibet and investigated their potential contribution to carbon sequestration. The AM fungi were abundant and diverse. AM fungal diversity was significantly higher in grassland than in forest or arable land. Significant differences in AM fungal community composition were found among different land use types. The relative abundance of operational taxonomic units (OTUs) in forest and grassland were positively related to glomalin-related soil protein (GRSP), soil organic carbon, macroaggregates, and the unprotected and physically protected carbon, while the AM fungal community in arable soils was dominated by a few OTUs which were positively linked to soil pH. Changes in GRSP content were closely related to water-stable macroaggregates and carbon storage in grassland and forest soils but not in arable soil. Given the inevitable trend toward agricultural management this study emphasizes the need to implement effective agricultural practices that can enhance AM fungal activity to maintain soil quality and carbon sequestration for the sustainable development of this fragile ecosystem.

Improvement of yield, pest control and Si nutrition of rice by rice-water spinach intercropping

Intercropping is an effective agricultural practice for crop production, resource utilization, and pest control. However, aquatic crops (e.g., rice) intercropping is relatively rare. Field experiments of two years/four seasons (early and late seasons in 2012, 2013) was carried out to test the effects of rice-water spinach intercropping on yield, disease and pest control, and Si, N nutrition of rice plant in the present study. The experiment contained three treatments including rice monoculture, water spinach monoculture and rice-water spinach intercropping with three replicates by randomized block design. Results showed that rice-water spinach intercropping significantly reduced the incidence of disease and pest of rice, with a reduction of rice sheath blight by 17.3%–50.6% and rice leaf folders by 5.1%–58.2%. For yield, intercropping resulted in an increase of rice yield by 45.1%–71.7% in early season and 20.9%–34.3% in late season, but a decrease of water spinach yield by 14.1%–37.1% in early season and 3.8%–18.3% in late season. However, rice-water spinach intercropping gave a higher land equivalent ratio (1.02–1.17) therefore improved land utilization efficiency. Furthermore, intercropping significantly increased Si concentration, Si and N absorption in rice leaves in ripening stage compared with rice monoculture. Our findings suggest that rice-water spinach intercropping exhibits yield advantage for rice or total yield, improves Si nutrition of rice and provides an environmentally sound approach in controlling disease and pest.

Increasing soil carbon storage: mechanisms, effects of agricultural practices and proxies. A review

The international 4 per 1000 initiative aims at supporting states and non-governmental stakeholders in their efforts towards a better management of soil carbon (C) stocks. These stocks depend on soil C inputs and outputs. They are the result of fine spatial scale interconnected mechanisms, which stabilise/destabilise organic matter-borne C. Since 2016, the CarboSMS consortium federates French researchers working on these mechanisms and their effects on C stocks in a local and global change setting (land use, agricultural practices, climatic and soil conditions, etc.). This article is a synthesis of this consortium’s first seminar. In the first part, we present recent advances in the understanding of soil C stabilisation mechanisms comprising biotic and abiotic processes, which occur concomitantly and interact. Soil organic C stocks are altered by biotic activities of plants (the main source of C through litter and root systems), microorganisms (fungi and bacteria) and ‘ecosystem engineers’ (earthworms, termites, ants). In the meantime, abiotic processes related to the soil-physical structure, porosity and mineral fraction also modify these stocks. In the second part, we show how agricultural practices affect soil C stocks. By acting on both biotic and abiotic mechanisms, land use and management practices (choice of plant species and density, plant residue exports, amendments, fertilisation, tillage, etc.) drive soil spatiotemporal organic inputs and organic matter sensitivity to mineralisation. Interaction between the different mechanisms and their effects on C stocks are revealed by meta-analyses and long-term field studies. The third part addresses upscaling issues. This is a cause for major concern since soil organic C stabilisation mechanisms are most often studied at fine spatial scales (mm–μm) under controlled conditions, while agricultural practices are implemented at the plot scale. We discuss some proxies and models describing specific mechanisms and their action in different soil and climatic contexts and show how they should be taken into account in large scale models, to improve change predictions in soil C stocks. Finally, this literature review highlights some future research prospects geared towards preserving or even increasing C stocks, our focus being put on the mechanisms, the effects of agricultural practices on them and C stock prediction models.

The effects of agricultural practices and cultivation abandonment on plant communities in rice fields and the significance of rice fields as habitat for wetland species on Sado Island, Niigata Prefecture, Japan

The effects of agricultural practices and cultivation abandonment on plant communities in rice fields and the significance of rice fields as habitat for wetland species on Sado Island, Niigata Prefecture, Japan

Do Varying Aquatic Plant Species Affect Phytoplankton and Crustacean Responses to a Nitrogen-Permethrin Mixture?

Hydraulically connected wetland microcosms vegetated with either Typha latifolia or Myriophyllum aquaticum were amended with an NH4NO3 and permethrin mixture to assess the effectiveness of both plant species in mitigating effects of the pollutant mixture on phytoplankton (as chlorophyll a) and Hyalella azteca. Phytoplankton grew in response to increased NH4NO3 in the presence of all plant species, but was unaffected by exposure to permethrin. H. azteca responses occurred rapidly (0.17days), was mitigated within 1-2days, and aqueous toxicity was unaffected by plant species type. A toxic unit model approach ascertained primary toxicity was permethrin with minimal additional toxicity from NH4NO3. Varying aquatic plant species had only modest influences on phytoplankton responses and no observable influence on animal responses during nitrogen-permethrin mixture exposures. As a result, both T. latifolia and M. aquaticum can be used as part of an effective agricultural best-management practice system for mitigating pollutant impacts of agricultural run-off.

Enzymatic biofilm digestion in soil aggregates facilitates the release of particulate organic matter by sonication

Abstract. The stability of soil aggregates against shearing and compressive forces as well as water-caused dispersion is an integral marker of soil quality. High stability results in less compaction and erosion and has been linked to enhanced water retention, dynamic water transport and aeration regimes, increased rooting depth, and protection of soil organic matter (SOM) against microbial degradation. In turn, particulate organic matter is supposed to support soil aggregate stabilization. For decades the importance of biofilm extracellular polymeric substances (EPSs) regarding particulate organic matter (POM) occlusion and aggregate stability has been canonical because of its distribution, geometric structure and ability to link primary particles. However, experimental proof is still missing. This lack is mainly due to methodological reasons. Thus, the objective of this work is to develop a method of enzymatic biofilm detachment for studying the effects of EPSs on POM occlusion. The method combines an enzymatic pre-treatment with different activities of α-glucosidase, β-galactosidase, DNAse and lipase with a subsequent sequential ultrasonic treatment for disaggregation and density fractionation of soils. POM releases of treated samples were compared to an enzyme-free control. To test the efficacy of biofilm detachment the ratio of bacterial DNA from suspended cells and the remaining biofilm after enzymatic treatment were measured by quantitative real-time PCR. Although the enzyme treatment was not sufficient for total biofilm removal, our results indicate that EPSs may attach POM within soil aggregates. The tendency to additional POM release with increased application of enzymes was attributed to a slight loss in aggregate stability. This suggests that an effect of agricultural practices on soil microbial populations could influence POM occlusion/aggregate stability and thereby carbon cycle/soil quality.

New insight into the Delia platura Meigen caused alteration in nutrient content of soybean (Glycine max L. Merill).

Climate change has brought about an increasing level of seedcorn maggot (Delia platura Meigen, 1826) (Diptera: Anthomyiidae) damage in Hungary. In order to have a more accurate understanding of the effects of these plant injuries induced by the larvae of D. platura, the nutrient content of soybean (Glycine max L. Merill.) was studied. Our results show that the moisture, raw fat, raw fibre, and raw ash content of the batches damaged by D. platura were significantly less in comparison with that of the control samples. In response to the deleterious effect of the insect, the infected soybean plants showed forced ripening (P = 0.004) (P > 0.05). The difference of moisture content between damaged and control samples was 2.30% on average. The fact of nutritional value loss was also reflected by the alteration of sugar mobilisation. As the result of this experiment the sucrose breakdown to glucose and fructose during the germination was significantly slower in the damaged seeds than that of the control ones. Overall, this late and surprising damage caused by D. platura led to the forced ripening of the affected soybean plants and a significant change in their nutritional values. Based on the herein reported results, it is presumable that in cases when the current climatic extremities, which are envisaged to occur more frequently in the future, and effects of agricultural practices will be coincided in the future a qualitative change of the produced soybean batches can be expected through the damage caused by this fly species.

Gall-ID: tools for genotyping gall-causing phytopathogenic bacteria.

Understanding the population structure and genetic diversity of plant pathogens, as well as the effect of agricultural practices on pathogen evolution, is important for disease management. Developments in molecular methods have contributed to increase the resolution for accurate pathogen identification, but those based on analysis of DNA sequences can be less straightforward to use. To address this, we developed Gall-ID, a web-based platform that uses DNA sequence information from 16S rDNA, multilocus sequence analysis and whole genome sequences to group disease-associated bacteria to their taxonomic units. Gall-ID was developed with a particular focus on gall-forming bacteria belonging to Agrobacterium, Pseudomonas savastanoi, Pantoea agglomerans, and Rhodococcus. Members of these groups of bacteria cause growth deformation of plants, and some are capable of infecting many species of field, orchard, and nursery crops. Gall-ID also enables the use of high-throughput sequencing reads to search for evidence for homologs of characterized virulence genes, and provides downloadable software pipelines for automating multilocus sequence analysis, analyzing genome sequences for average nucleotide identity, and constructing core genome phylogenies. Lastly, additional databases were included in Gall-ID to help determine the identity of other plant pathogenic bacteria that may be in microbial communities associated with galls or causative agents in other diseased tissues of plants. The URL for Gall-ID is http://gall-id.cgrb.oregonstate.edu/.

Variation Characteristics of Inorganic Phosphorus in Purple Soil Profile Under Different Conservation Tillage Treatments

In this study the effects of tillage methods (rice-winter paddy field conventional farming, CF; rice-winter paddy field combing ridge with no-tillage, RNT1; rice-wheat or rape combing ridge with no-tillage, RNT2; rice-wheat or rape conventional paddy-upland rotation tillage, CR) on purple soil profile of different forms of inorganic phosphorus distribution characteristics were investigated in a long-term experimental site established in 1990, Chongqing City, China. The results showed that compared to the status before the experiment, the total phosphorus, available phosphorus and various morphologies of inorganic phosphorus all increased to a certain degree in the soils with different long-term tillage treatments,and the contents of different forms of inorganic phosphorus in soil size ranked as RNT2> CF> CR> RNT1. Except that the contents of Fe-P in the lower layer were higher than those in the upper layer, contents of Ca2-P, Ca8-P, Al-P, Ca10-P and O-P in the arable layers were all higher than those in the lower layers. The effects of farming practices on the availability of various phosphorus forms were significant. They were in the order of CR> RNT> CF. Long-term conventional paddy-upland rotation tillage was more advantageous to crops in the absorption of phosphorus. It was shown by relevant analysis that the contribution of various groups of inorganic phosphorus to purple soil was in the order of Ca2-P(0.9369)> Al-P(0.9158)> Ca8-P(0.9012)> Fe-P(0.8287)> Ca10-P(0.8059)> O-P(0.7472).

Effect of agricultural practices and coastal constraints on soil microbial functional properties in Mediterranean olive orchards

SummaryThis research examines how agricultural practices commonly used in Lebanese olive tree orchards (no‐tillage, co‐culture with Vicia sativa L. var. sativa and conventional tillage) affect soil microbial and chemical characteristics, and whether this depends on geographical context (coastal or inland areas). Four coastal and four inland sampling sites were selected, and at each site three practices were considered (one practice per plot). For each plot (200 m2), 20 soil samples were taken and homogenized to obtain a composite sample from which soil was characterized chemically and microbiologically. Differences in chemical properties (smaller N content and alkyl C fraction in the coastal area) depended on geographical location rather than on agricultural practices. For microbial properties, catabolic structure varied with geographical location; the index of catabolic diversity was larger in the coastal area. Importantly, the basal respiration was similar in both areas although the soil contained less nitrogen (N) in the coastal area. The negative effect of conventional tillage on microbial functioning of the soil was observed only in relation to geographical location. We found that this effect was reduced by co‐culture, for example with Vicia sativa L. var. sativa. Our study reveals that geographical location affects how agricultural practices affect soil properties (in the coastal area, enhanced mineralization of labile C and change in microbial catabolic profile). This suggests that soil management should take into account the environmental conditions specific to coastal areas, which enhance the adverse effects of conventional tillage. Consequently, this type of management should not be implemented in coastal areas of the Mediterranean.HighlightsWhat are the appropriate practices for olive trees under coastal constraints? Coastal‐specific constraints were the main factors controlling microbial communities. Agricultural practices affected enzyme activities depending on distance from the sea. Tillage should not be implemented in coastal areas of the Mediterranean.

Effect of farming practices and farm history on incidence of coconut lethal yellowing in Mozambique

Management of coconut (Cocos nucifera) lethal yellowing disease (CLYD), which has killed about eight million coconut trees in Mozambique, has proved challenging. The objective of this study was to investigate the impact of farming practices and related history, on the CLYD incidence in Mozambique. The methodology included a socioeconomic questionnaire to the households and direct observations on the palm farms. The collected data were analysed using logistic regression. Five out of 11 explanatory variables tested, namely farm age, availability of other palm species on the coconut farm, type of coconut varieties grown, root cut practices, and intercropping had a significant (P< 0.05) effect on CLYD incidence. Coconut farms <10 years had higher odds of higher disease incidence compared to the farms between 10 to 40 years old. The presence of other palm species in the coconut farms had two times higher odds of having higher disease incidence levels compared to farms without other palm species. Tall coconut varieties were likely to be more tolerant to CLYD compared to dwarf varieties. Coconut farms with some kind of intercropping had two times higher odds of having higher disease incidence levels compared to pure stands. The practice of cutting coconut roots had three times higher odds of having high disease incidence levels compared to non-practicing farms. Farm age, availability of other palm species on the coconut farm, type of coconut varieties grown, root cut practices and intercropping need to be considered for integrated CLYD management.Key Words: Cocos nucifera, inter cropping, logistic regression

An ecological footprint approach to environmental–economic evaluation of farm results

Farmers' cultivation choices affect the natural cycles of crops and impact their production. By assessing the farming activities, as influenced by crop types, land suitability and cultivation choices, the effectiveness of agricultural practices in terms of environmental impact can be evaluated. The study of the relationships between agriculture, environment and economic performance should be deepened, by considering the connection between agricultural activities and the use of natural resources beyond the economic issues, which are often taken as the unique or, at least, the main goal of human activities.The aim of this paper is to assess and to analyse in a comparative way the environmental and economic results of a crop production system at farm level.The methodology for the evaluation of environmental performance is based on a modified version of the Ecological Footprint account, used to measure the demand for natural resources linked to the farm's operations, which is compared with the Biocapacity of the crop system itself. The economic performances are assessed by means of crops' analytical budgets.The results provided by the case study analysis show that the considered farm cropping system reports an overall positive ecological balance (+2.4gha) together with an acceptable gross margin (16,200€). It emerges that crops with negative environmental performances sustain farm income, while the crops with a positive ecological balance bring a very limited contribution to economic profitability.Such results lead to some considerations about the importance of carefully considering the trade-off between economic and environmental consequences of farming activities in order to drive farmers towards a more sustainable behaviour.

Effects of agricultural practices on soil and microbial biomass carbon, nitrogen and phosphorus content: a preliminary case study

Abstract. In this study we assessed the C : N : P ratios in soil and soil microbial biomass subject to conventional farming and three different organic farming practices. The results showed that microbial biomass was P-limited in soils subject to conventional farming and to organic farming with alfalfa green manure. Organic farming with compost amendment showed the best results in terms of microbial biomass carbon, nitrogen and phosphorus (CNP).

Teaching and Learning of ‘Water for Agriculture’ in Primary Schools in Lesotho, South Africa and Zimbabwe

Teaching youths about the subject of water for agriculture is vital in southern Africa where climate adaptation is imperative. Fresh water is a critical natural resource experiencing dangerous scarcity globally, with climate change and variability being key drivers. Agriculture consumes most of the allocated water in most of the southern African countries, so this sector needs particular water harvesting and conservation education. The Food and Agriculture Organisation (FAO) reported that 93% of cultivated land in southern Africa was rain-fed at the beginning of the 21st century. Drought hinders effective agricultural practices in poor-rainfall areas and is a common feature in most southern African countries. Increasingly frequent drought events affect Lesotho, South Africa and Zimbabwe chronically due to climate variability and change. These three countries have school curricula that carry agricultural and sustainability learning to varying extents. Agriculture is taught as a science subject, and tends to be inclined towards normative technicist approaches at the expense of traditional and innovative sustainability practices. This omission in curriculum development and teaching may miss the opportunity to learn from lessons offered by these traditional and innovative systems that have demonstrated resilience to climate variability and change. This paper explores the opportunities and enablers of sustainability learning and relevance in the primary school agriculture curricula of these three countries. The paper argues for inclusion of sustainable agricultural water learning as an act of educational quality and relevance that reflects 21st century socio-ecological, agro-climate and socioeconomic challenges in southern Africa. Key words: primary school, water for agriculture, rainwater harvesting and conservation, learning.

Warmer and Wetter Soil Stimulates Assimilation More than Respiration in Rainfed Agricultural Ecosystem on the China Loess Plateau: The Role of Partial Plastic Film Mulching Tillage.

Effects of agricultural practices on ecosystem carbon storage have acquired widespread concern due to its alleviation of rising atmospheric CO2 concentrations. Recently, combining of furrow-ridge with plastic film mulching in spring maize ecosystem was widely applied to boost crop water productivity in the semiarid regions of China. However, there is still limited information about the potentials for increased ecosystem carbon storage of this tillage method. The objective of this study was to quantify and contrast net carbon dioxide exchange, biomass accumulation and carbon budgets of maize (Zea maize L.) fields under the traditional non-mulching with flat tillage (CK) and partial plastic film mulching with furrow-ridge tillage (MFR) on the China Loess Plateau. Half-hourly net ecosystem CO2 exchange (NEE) of both treatments were synchronously measured with two eddy covariance systems during the growing seasons of 2011 through 2013. At same time green leaf area index (GLAI) and biomass were also measured biweekly. Compared with CK, the warmer and wetter (+1.3°C and +4.3%) top soil at MFR accelerated the rates of biomass accumulation, promoted greater green leaf area and thus shortened the growing seasons by an average value of 10.4 days for three years. MFR stimulated assimilation more than respiration during whole growing season, resulting in a higher carbon sequestration in terms of NEE of -79 gC/m2 than CK. However, after considering carbon in harvested grain (or aboveground biomass), there is a slight higher carbon sink (or a stronger carbon source) in MFR due to its greater difference of aboveground biomass than that of grain between both treatments. These results demonstrate that partial plastic film mulched furrow-ridge tillage with aboveground biomass exclusive of grain returned to the soil is an effective way to enhance simultaneously carbon sequestration and grain yield of maize in the semiarid regions.