EFFECT OF CROP ROTATION AND FERTILIZATION ON SOME BIOLOGICAL PROPERTIES OF A LOAM IN SOUTHWESTERN SASKATCHEWAN

1984 ◽  
Vol 64 (3) ◽  
pp. 355-367 ◽  
Author(s):  
V. O. BIEDERBECK ◽  
C. A. CAMPBELL ◽  
R. P. ZENTNER

Effects of rotation length, fallow-substitute crops, and N and P fertilizer on some physical and biological properties of a Brown Chernozemic loam in southwestern Saskatchewan were determined over a period of 16 yr. After 12 yr, the erodible fraction in the top 15 cm of soil (i.e., < 0.84 mm) was inversely related to trash conserved and thus rotation length. Soil organic N (in the top 15 cm) increased from 0.18 to 0.20% in continuous-type rotations receiving an average 32 kg N∙ha−1∙yr−1 and adequate P, but it did not increase in continuous wheat receiving P only, nor in fallow rotations, except the one that included fall rye (Secale cereale L.). This N increase was credited partly to fertilizer and partly to more efficient use and cycling of subsoil NO3-N via plant roots and crop residues. After 10 yr, well-fertilized continuous-type rotations had a 13% greater C content than fallow rotations and continuous wheat receiving only P. In the top 7.5 cm of soil under the four rotations examined in detail, bacterial numbers were lowest in fallow-wheat, intermediate in fallow-wheat-wheat, higher in continuous wheat receiving N and P, and highest in continuous wheat receiving only P. Similarly, microbial biomass C in these four rotations was 180, 226, 217 and 357 kg∙ha−1; biomass N was 52, 65, 54 and 72 kg∙ha−1; and biomass C/N ratios were 3.4, 3.5, 4.1 and 5.1, respectively. Differences in biomass C/N, respiration rates and numbers of bacteria, actinomycetes and yeasts indicated both quantitative and qualitative microbial changes and reflected increasing rotation length and differences in fertility. Potentially mineralizable N (No) was 192 kg∙ha−1 for adequately fertilized continuous wheat, and exceeded No in fallow-wheat by 45%, in fallow-wheat-wheat by 17% and in continuous wheat receiving only P by 25%. The latter rotation contained a large but fairly inactive microbial population. We concluded that land degradation caused by frequent summerfallowing can be arrested and the decline in amount and quality of organic matter reversed by use of available agronomic technology. Key words: Microbial biomass, microbial activity, potentially mineralizable N, respiration, soil erodibility

Soil Research ◽  
1987 ◽  
Vol 25 (4) ◽  
pp. 461 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer

The dynamics of nitrogen mineralization potential (N0) and mineralization rate constant (k) were studied in six major soils which had been used for cereal cropping for up to 20-70 years. In the top 0.1 m layer of virgin soils, N0 varied from 110 � 22 mg kg-1 soil (Riverview) to 217 � 55 mg kg-1 soil (Langlands-Logie), representing about 13% and 11%, respectively, of total N in these soils. Upon cultivation and cropping, N0 declined by 1 7 � 0.5 mg kg-1 yr-1 (Riverview) to 4.8 � 2.0 mg kg -1 yr -1 (Billa Billa). This represented < 20% of total N lost annually from the top layer (0-0.1 m depth) of these soils. The k values varied less than the N0 values, both within and among soils, and were also less affected by cultivation than N0. The mineralizable N in cultivated soil during cropping for periods up to 70 years can be estimated from N0 and k values, taking No as 5% of total N for soils of <40% clay and 15% of total N for soils of >40% clay and k as 0.066 week-1 at 40�C (0.027 week-1 and 0.054 week-1 at 25�C and 35�C, respectively). Organic C and N contained in the 'stabilized' microbial biomass (determined after 30 weeks' pre-incubation) accounted for 1.7-38% of total organic C and 2.0-5.1% of total N in the six soils studied. The microbial biomass C and N declined with cultivation in most soils, biomass N representing 10-23% of the total annual loss of N0. The microbial biomass, urease activity and total N, in addition to a number of other soil properties [e.g. light-fraction (<2 Mg m-3) C, sand-size C, CEC and ESP], were significantly correlated with N0 and k, thus indicating the existence of a myriad of environments for the activity, association and stability of microbial biomass and potentially mineralizable N in soil.


Author(s):  
P. Padmavathi ◽  
I. Y.L.N Murthy ◽  
M. Suresh

A field experiment was conducted to study the effect of nutrient management practices on the performance of soybean - safflower sequence in Vertisols. The safflower equivalent yield (2418 kg/ha-1); gross returns (Rs. 53196/ha-1); net returns (Rs 33734/ha-1) and B:C ratio (2.8) were significantly superior either with the application of NPK to the system + 5 t FYM/ha to safflower; or NPK to the system + soybean residues to safflower; or NPK to the system + both crop residues. Similar trend was also observed with respect to soil health indicators viz., soil respiration (108 mg C/g soil/10 days), microbial biomass C (284 mg C/g soil), microbial biomass N (41.9 mg N/g soil), mineral N (13.8 mg N/g soil) and net N mineralization (5.4 mg N/g soil/ 10 days). Significant improvement was observed in terms of PGPR and Trichoderma sp were found when NPK + crop residues were applied to the system.


2017 ◽  
Vol 38 (5) ◽  
pp. 2887 ◽  
Author(s):  
Julierme Zimmer Barbosa ◽  
Wilian Carlo Demetrio ◽  
Caroline Malinski Silva ◽  
Jair Alves Dionísio

Few studies have evaluated the effect of earthworms on plants and biological soil attributes, especially among legumes. The objective of this study was to evaluate the influence of earthworms (Amynthas spp.) on growth in the common bean (Phaseolus vulgaris L.) and on soil biological attributes. The experiment was conducted in a greenhouse using a completely randomized design with five treatments and eight repetitions. The treatments consisted of inoculation with five different quantities of earthworms of the genus Amynthas (0, 2, 4, 6, and 8 worms per pot). Each experimental unit consisted of a plastic pot containing 4 kg of soil and two common bean plants. The experiment was harvested 38 days after seedling emergence. Dry matter and plant height, soil respiration, microbial respiration, microbial biomass, and metabolic quotient were determined. Earthworm recovery in our study was high in number and mass, with all values above 91.6% and 89.1%, respectively. In addition, earthworm fresh biomass decreased only in the treatment that included eight earthworms per pot. The presence of earthworms increased the plant growth and improved soil biological properties, suggesting that agricultural practices that favor the presence of these organisms can be used to increase the production of common bean, and the increased soil CO2 emission caused by the earthworms can be partially offset by the addition of common bean crop residues to the soil.


1992 ◽  
Vol 72 (4) ◽  
pp. 403-416 ◽  
Author(s):  
C. A. Campbell ◽  
V. O. Biederbeck ◽  
R. P. Zentner ◽  
S. A. Brandt ◽  
M. Schnitzer

The influence of five crop rotations and the rotation phases (i.e., rotation-yr) on some soil organic matter characteristics was investigated in a long-term (23 yr) study carried out on an Orthic Dark Brown Chernozemic soil at Scott, Saskatchewan. The cropping systems included different cropping frequencies and crop types (cereals, oilseeds, and legume-hay). Soil samples were taken from the 0- to 7.5- and 7.5- to 15-cm depths in mid-September 1988, 2 wk after harvest of the grain crops (i.e., 2 mo after hay harvest and plowdown). Most effects of rotations, and rotation phases, on soil biological characteristics assessed, were significant primarily in the top 7.5-cm soil depth. Increasing the cropping frequency did not increase soil organic matter. Excessive preseeding tillage of stubble plots may have masked any potential advantage provided by frequent cropping. Including alfalfa (Medicago sativa L.) hay crops in rotation with grain crops decreased soil organic matter in the fallow and grain crop rotation phases of rotations. This was likely due to increased moisture stress depressing associated cereal production in this semiarid environment. As expected, rotation phase did not influence soil organic C, but alfalfa under-seeded into barley (Hordeum vulgare L.) increased soil organic nitrogen. We believe this was due to crop residue inputs from the seedling alfalfa. Microbial biomass C and N, C mineralization, the specific respiratory activity (ratio of CO2-C respired/microbial biomass C) and hydrolyzable amino acids were also greater in the rotation phases in which barley was underseeded with alfalfa. Carbon mineralization and specific respiratory activity were directly related to estimated crop residue-C returned to soil, but not residue-N. However, both were increased by including alfalfa in the rotation. Carbon mineralization and specific respiratory activity were more sensitive indexes of soil organic matter quality than biomass C and N per se. Hydrolyzable amino acids and amino sugars responded to the treatments in a manner similar to total soil organic N. Relative molar distribution of amino acids was unaffected by crop rotation or rotation phase. Potentially mineralizable N in this soil was low compared to other Canadian prairie soils, even though the total soil organic N of the Scott soil was relatively high. We concluded that (i) all soil biochemical characteristics studied are useful for assessing soil quality changes; (ii) when studying soil changes, thin (0- to 7.5-cm) soil slices are more likely to reveal treatment effects than thicker slices; (iii) all rotation phases should be analyzed whenever forage legumes are constituents of crop rotations. Key words: C mineralization; microbial biomass, amino acids, N mineralization, specific respiratory activity


1969 ◽  
Vol 100 (2) ◽  
pp. 123-140
Author(s):  
Ian C. Pagán-Roig ◽  
Joaquín A. Chong ◽  
José A. Dumas ◽  
Consuelo Estévez de Jensen

The objective of this work was to measure the effects of repeated short-term organic amendments that we termed soil treatment management cycles (STMC) on physical and biological properties of a San Antón series soil. Each STMC lasted 60 days and consisted of incorporating 5% organic matter from coffee pulp compost; the planting, growth and incorporation of an intercrop of four green manure species; and the application of mycorrhizae and compost tea. The treatments were labeled: CL0, CL1, CL2 and CL3; where CL0 was the control, CL1 received one STMC, CL2 and CL3 received two and three STMC, respectively. The STMC intended to mimic the overall effect of a sustainable agricultural system, not to measure the individual effects of the practices. All treatments (CL1, CL2, CL3) showed an increase in soil organic matter (p≤0.05). When compared to the CL0 control, saturated hydraulic conductivity increased and bulk density decreased in all soils. Soil macroporosity was significantly increased by CL2 and CL3. Soil aggregate stability increased in CL1, CL2 and CL3 plots. Microbial biomass C increased in treatment CL3, and microbial biomass N increased in CL2 and CL3. The production of stable aggregates was correlated to humic acid content and positively influenced all other physical parameters assessed in this study. The STMC had a positive impact on soil properties by increasing the soil organic matter as well as the humic acid fraction. Soil macroporosity, defined as porosity with radius > 38 µm, was significantly increased by treatments CL2 and CL3. All of the organic matter fractions, including total organic matter, humic acid content, microbial biomass C and microbial biomass N were significantly increased by one or more STMC.


1986 ◽  
Vol 66 (4) ◽  
pp. 601-614 ◽  
Author(s):  
C. A. CAMPBELL ◽  
V. O. BIEDERBECK ◽  
F. SELLES ◽  
M. SCHNITZER ◽  
J. W. B. STEWART

The effects of application of manure and P fertilizer on wheat yields in a fallow-wheat-wheat rotation on a Black Rego Chernozemic clay soil have been studied for 36 yr. The objective of this study was to identify the effects of manure on soil characteristics that could be related to the reported progressive yield increases over time and an apparent improvement in soil tilth. Soil samples were taken in 1982 from the check (no treatment), and from treatments receiving 13.4, 20.2 and 26.9 t ha−1 of manure applied each fallow year, and 112 kg ha−1 of seed-placed 11-48-0 applied to wheat after summerfallow. Soil physical and P-related parameters were determined for depth increments to 30 cm; the total-N and 15N data to 90 cm; other data were for the 0- to 7.5-cm depth. Manure had no effect on bulk density or hydraulic conductivity. However, it increased the total C and humic acid (HA) content of the soil, the percent of soil C as HA-C, the C concentration in humin, and the percent of total soil N as humin-N. Manure significantly increased the percent of HA-N but not humin-N present as amino acid and amino sugar-N, but increased amino acids and the amino sugars in the humin hydrolysate. The net rate of N mineralization and the available forms of inorganic P were all increased significantly by manure. The natural 15N-abundance technique showed that a significant though small proportion of soil N was derived from manure. Manure had no effect on soil microbial biomass C and N, soil respiration, and the quantity of potentially mineralizable N. Applied P had no effect on N-related parameters measured; its effect on available P was not measured. It was concluded that manure increased crop yields by improving the N- and P-supplying power of the soil, and improving the physical environment of the soil through its effects on the humic colloids. Key words: Humic substances, soil P fractions, soil biological properties, natural 15N abundance, net N mineralization


1996 ◽  
Vol 76 (4) ◽  
pp. 469-472 ◽  
Author(s):  
J. W. Paul ◽  
E. G. Beauchamp

A spring application of dairy cattle slurry (300 kg total N ha−1) on high- and low-fertility sites resulted in higher microbial biomass C during the growing season than on a control soil or a soil receiving 100 kg N ha−1 as urea. Microbial biomass C was also significantly higher on the high-fertility site and was reflected in greater N mineralization and N uptake by corn. There was no greater net N mineralization in the manured soil than in the control or fertilized soil as would be expected as a result of higher microbial biomass C and significant organic N contribution from the manure. Key words: Animal manure, nitrogen mineralization, corn, grain yields, soil fertility


Soil Research ◽  
1999 ◽  
Vol 37 (5) ◽  
pp. 847 ◽  
Author(s):  
P. D. McIntosh ◽  
R. S. Gibson ◽  
S. Saggar ◽  
G. W. Yeates ◽  
P. McGimpsey

A question of economic, social, and land-use importance in the predominantly steep South Island high country tussock grasslands of New Zealand is whether these lands can be sustainably farmed by oversowing introduced grasses and legumes and using fertilisers. To help answer this question, we compared vegetation and soil chemical, biochemical, and biological properties on Brown soils (Dystrudepts) on adjacent land areas which have been differently managed since 1978. One area had never been fertilised or oversown. The other had been oversown with grasses and clovers and received about 1100 kg/ha of sulfur-superphosphate between 1979 and 1997. Oversowing and fertilising reduced the amount of bare ground and transformed the vegetation to a species composition dominated by the introduced adventives Anthoxanthum odoratum and Agrostis capillaris. Fertilising raised soil carbon (C) and nitrogen (N) content, increased A-horizon thickness, and raised exchangeable cation values. All of the phosphorus (P) applied to the fertilised area was accounted for in the top 15 cm of soil, but has accumulated in the relatively unavailable organic form. Oversowing and fertilising significantly (P < 0 . 05) increased microbial biomass C, N, and P relative to values in unfertilised soils. The microbial biomass C: N and C: P ratios were significantly (P < 0 . 05) lower in fertilised soils. Fertilised soils had significantly more (P < 0 . 05) mineralised N than unfertilised soils. Populations of 5 groups of soil fauna (Scarabaeidae, nematodes, enchytraeids, rotifers, tardigrades) were higher in fertilised soils. Nematode species parasitic or pathogenic for clovers were present in greater numbers on fertilised soils. A combination of fertility decline (in particular, P immobilisation as organic P) and nematode damage may be the reason for the low clover cover on fertilised sites, and may explain the widely observed clover ‘flush’ and decline common to oversown high country. We conclude that there is no simple measure of ‘soil quality’ that can be used as a sustainability indicator in moist New Zealand high country. Nor can sustainability be judged purely on biological, biochemical, and chemical critieria. Although many of the effects associated with oversowing and fertilising, such as increased organic matter content of A horizons and increased biological activity, are positive, these effects must be balanced against the economic risk associated with being committed to a high-input farming system, the loss of low-producing but resilient native species, and increase of plant-pathogenic nematodes.


2017 ◽  
Vol 77 (1) ◽  
pp. 16-21 ◽  
Author(s):  
A. S. F. Araújo ◽  
L. B. Magalhaes ◽  
V. M. Santos ◽  
L. A. P. L. Nunes ◽  
C. T. S. Dias

Abstract The aim of this study was to measure soil microbial biomass and soil surface fauna in undisturbed and disturbed Cerrado sensu stricto (Css) from Sete Cidades National Park, Northeast Brazil. The following sites were sampled under Cerrado sensu stricto (Css) at the park: undisturbed and disturbed Css (slash-and-burn agricultural practices). Total organic and microbial biomass C were higher in undisturbed than in disturbed sites in both seasons. However, microbial biomass C was higher in the wet than in the dry season. Soil respiration did not vary among sites but was higher in the wet than in the dry season. The densities of Araneae, Coleoptera, and Orthoptera were higher in the undisturbed site, whereas the densities of Formicidae were higher in the disturbed site. Non-metric multidimensional scaling analysis separated undisturbed from disturbed sites according to soil biological properties. Disturbance by agricultural practices, such as slash-and-burn, probably resulted in the deterioration of the biological properties of soil under native Cerrado sensu stricto in the Sete Cidades National Park.


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