INTERACTIONS BETWEEN BIOTIC COMPONENTS IN SOILS AND THEIR MODIFICATION BY MANAGEMENT PRACTICES IN CANADA: A REVIEW

1973 ◽  
Vol 53 (3) ◽  
pp. 425-441 ◽  
Author(s):  
J. T. MILLS ◽  
B. P. ALLEY

Soil microfloral and faunal components are vitally concerned with soil fertility, plant growth, and decomposition of plant residues and pesticides and are interrelated in a complex manner. Interactions occurring between dominant soil biotic components have been compiled and each interaction rated according to its importance in the literature. This review is intended as a framework on which further information can be superimposed and the relative importance of interactions revised. The general format used is as follows: functions of major biotic components; their interactions; the effects of management practices, excluding pesticides, on the components; and the effects of pesticides. A concluding section suggests where further research is needed. In particular, information is required on the effects of Collembola, mites, enchytraeid worms, and protozoa on actinomycetes; of discing and severe winter conditions on faunal and microfloral populations; of seed treatment fungicides on soil fauna; of lindane, dasanit, furadan, and lannate insecticides on fungi, bacteria, and actinomycetes; of lindane and diazinon on nematodes, and of dasanit, furadan, and lannate on earthworms, enchytraeid worms, Collembola, and mites. Also, more information is needed on the effects of barban, diallate, and triallate herbicides on the major soil biota and of MCPA on the soil fauna.

Author(s):  
J. Hodgson

Recent assessments of the relative importance of stocking rate. stocking policy and grazing management on the output from pastoral systems are used as a starting point to argue the need for objective pasture assessments to aid control of livestock enterprises to meet production targets. Variations in stocking rates, stocking policy and other management practices all provide alternative means of control of pasture conditions which are the major determinants of pasture and animal performance. Understanding of the influence of pasture conditions on systems performance should provide a better basis for management control and for Communication between farmers, extension officers and researchers. Keywords: Stocking rate, pasture condition, pasture cover


1968 ◽  
Vol 46 (5) ◽  
pp. 835-843 ◽  
Author(s):  
John E. Bishop

Orconectes propinquus and Cambarus robustus from the Speed River, Sunfish Lake, and Laurel Creek, harbor two branchiobdellids, Cambarincola chirocephala and Pterodrilus distichus. Both adult and cocoon populations of the dominant species (C. chirocephala) are proportional to the size of the host throughout the year, except that first-year crayfish are free of cocoons. The reduction in total number of commensals from autumn to spring can be attributed to severe winter conditions. A subrostral site of preference for adult branchiobdellid attachment, and a dominant abdomen I and II site for cocoon deposition are indicated for O. propinquus. On C. robustus, adults are most commonly found on the antennal bases and among the maxillipeds, and cocoons on the last live abdominal sternites. No host specificity is evident although an unidentified Cambarus sp. from Sunfish Lake is free of commensals. Host incompatibility may explain this, but data from Laurel Creek indicate that silting of the microhabitat is responsible for loss of branchiobdellid population. The crayfish–branchiobdellid relationship is commensal, or at most facultatively parasitic, as adult worms can live without a host for extended periods. Serological testing of rabbit serum containing branchiobdellid antibodies against crayfish serum is negative. The dependence of the egg stage on the host for some undetermined factor or factors is discussed. An Asellus sp. fails to pick up the commensals even when exposed under ideal conditions for colonization.


2014 ◽  
Vol 9 (3) ◽  
pp. 243-252 ◽  
Author(s):  
Rob Leuven ◽  
Frank Collas ◽  
K. Remon Koopman ◽  
Jon Matthews ◽  
Gerard van der Velde

2018 ◽  
Vol 10 (9) ◽  
pp. 333 ◽  
Author(s):  
Ana Luiza Privado Martins ◽  
Glécio Machado Siqueira ◽  
Emanoel Gomes de Moura ◽  
Raimunda Alves Silva ◽  
Anágila Janenis Cardoso Silva ◽  
...  

Soil fauna play an important role in ecosystems, and in this context, it is important to better understand how the abiotic and biotic drivers of these organisms interact. We hypothesize that soil fauna are affected by different soil management practices, which has an influence on maize grain yields. The aim of this study was to evaluate the structure of soil fauna under different soil management practices and their associations with maize grain yield. The experiment was conducted in Maranhão, Brazil, in an area divided into 24 plots of 4 × 10 m in a randomized block design with six treatments with four replicates (R). Pitfall traps were placed in the area. The treatments were Leucaena leucocephala-Leucaena (L), nitrogen (N), humic acid + nitrogen (HA + N), nitrogen + Leucaena (N + L), humic acid + Leucaena (HA + L) and humic acid + nitrogen + Leucaena (HA + N + L). The soil fauna dominance, abundance, richness, Shannon-Wiener diversity index, Pielou evenness index and maize grain yield were determined. Formicidae was clearly affected by management with Leucaena, while Coleoptera was affected by management with nitrogen. Despite this, Isopoda and Diplura were the only groups associated with the maize yield. Although fauna abundance did not differ among treatments, it was related to the yield. This study confirms that the abundance and some taxa of soil fauna can influence yield and that these organisms can be used to increase agricultural sustainability.


1917 ◽  
Vol 8 (3) ◽  
pp. 385-417 ◽  
Author(s):  
E. J. Russell ◽  
A. Appleyard

The biochemical decomposition of plant residues and other organic matter in the soil is of fundamental importance for soil fertility. It causes the breaking down of coarse plant fragments which otherwise might open up the soil too much: it leads to the production of colloidal complexes known as humus which exert many beneficial effects both chemical and physical, and it brings about the formation of nitrates, the most important of the nitrogenous plant nutrients.


Agriculture ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Zhongqi He ◽  
Dan C. Olk ◽  
Haile Tewolde ◽  
Hailin Zhang ◽  
Mark Shankle

To achieve the optimal and diverse utilization of cotton (Gossypium hirsutum) plant residues in various agricultural, industrial, and environmental applications, the chemical composition of cotton biomass tissues across different plant parts (e.g., seed, boll, bur, leaves, stalk, stem, and root) is of essential information. Thus, in this work, we collected field-grown whole mature cotton plants and separated them into distinct biomass fractions including main stems, leaf blades, branches, petioles, roots, and reproductive parts (mid-season growth stage) or bur, peduncles/bract, and seed cotton (pre-defoliation stage). The contents of selected carbohydrates and amino acids in these cotton biomass materials were determined. Both essential and nonessential amino acids were enriched in cotton leaf blades and reproductive parts. The distribution pattern of the selected carbohydrates differed from that of amino acids—higher contents of carbohydrate were found in roots, main stems, and branches. Although glucose was the most abundant non-structural carbohydrate in cotton plant parts at mid-season, xylose was the most abundant in most plant parts at the pre-defoliation stage. Nutritional carbohydrates and amino acids were further accumulated in seeds at pre-defoliation. The information reported in this work would be helpful in exploring and optimizing management practices and processing strategies for utilizing cotton crop biomass materials as valuable and renewable natural resources.


Proceedings ◽  
2019 ◽  
Vol 30 (1) ◽  
pp. 35 ◽  
Author(s):  
Telak ◽  
Bogunovic ◽  
Rodrigo-Comino

Humans are the driving factor of soil erosion and degradation. Therefore, sustainable land management practices should be developed and applied. The aim of this study was to determine land management impacts on soil properties, soil loss and nutrient loss in 3 different treatments; grass-covered vineyard (GCV), tilled vineyard (TV), and tilled hazelnut orchard (HO). The study area is located in Orahovica, Croatia (45°31′ N, 17°51′ E; elevation 230 m) on ~7° slope. The soil under the study area was classified as a Stagnosol. 8 rainfall simulations (58 mm h−1, during 30 min, over 0.785 m2 plots) were performed at each treatment where the next data were noted: ponding time, runoff time, and collection of overland flow. Soil samples were taken for determination of mean weight diameter (MWD), water stable aggregates (WSA), P2O5 content, and organic matter content. Analyses of sediment revealed concentrations of P2O5 and N. All three treatments had significantly different values of MWD (GCV 3.30 mm; TV 2.94 mm; HO 2.16 mm), while WSA and organic matter significantly differs between GCV and HO. The infiltration rate showed no significant difference between treatments. Sediment yield was significantly the highest at the TV (21.01 g kg−1 runoff), while no significant difference was noted between GCV (2.91) and HO (6.59). Sediments of GCV treatment showed higher concentrations of P2O5 and N, compared to TV and HO. Nutrients loss was highest in the TV (450.3 g P2O5 ha−1; 1891.7 g N ha−1) as a result of highest sediment yield, despite the fact GCV had the highest nutrients concentrations. Results indicate that land management (and/or tillage) affects soil properties and their stability. Even tough HO was tilled and had the lowest values of organic matter, WSA, and MWD, measurements were performed immediately after tillage where the plant residues reduced potential erodibility of the soil. Such results reveal that tillage should be avoided in vineyard and hazelnut production in order to prevent soil and nutrient losses.


Author(s):  
Suzanne Visser

The impact of severe soil disturbance on soil fungal community composition and function and how this relates to the resultant decomposition/mineralisation process is very poorly understood. Consequently, research was conducted to determine: (a) to what degree fungal community structure and potential function are altered in a sub-alpine coal mine spoil (Luscar, Alberta), and (b) how do alterations in the fungal community affect patterns of fungal colonisation and decomposition of plant residues deposited on recently mined soil.


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