Performance of a simulation model describing protozoa-induced mineralization of bacterial C and N in a sandy loam

1992 ◽  
Vol 72 (3) ◽  
pp. 217-228 ◽  
Author(s):  
P. M. Rutherford ◽  
N. G. Juma
Keyword(s):  
N Mineralization ◽  
Sandy Loam ◽  
Simulated Data ◽  
State Variables ◽  
Clay Loam ◽  
Data Set ◽  
Half Saturation Constant ◽  
Loam Soil ◽  
C And N ◽  
Bacterial C

Mathematical modelling of a microcosm experiment provided a rigorous link between soil organism populations and the processes in the C and N cycles for a clay loam soil. In order to check the internal consistency of the model, we tested its performance with the data set obtained for a sandy loam. We empirically lowered the value of the half saturation constant for the protozoan consumption of bacteria from 175 to 50 (μg C g−1 soil) and initialized the state variables with the appropriate values. The model was also used to quantify the effect of texture on bacterial-protozoan interactions and flows of C and N using the simulated data for a clay loam and a sandy loam. The CO2-C evolved during the first 12 d was mainly due to glucose addition (180 μg C g−1 soil) and cycling of C in the soil (130 μg C g−1 soil). During this interval, C inputs into bacteria were 14-fold greater than the initial pool size. Protozoa increased total CO2-C evolution by 16% and increased net NH4-N mineralization 3.5-fold compared with the protozoa-minus treatment. Mineralization of bacterial C and N was more rapid in the sandy loam than in the clay loam. Key words: N mineralization-immobilization, bacteria, model, protozoa, Typic Cryoboroll, sandy loam

Simulation of protozoa-induced mineralization of bacterial carbon and nitrogen

1992 ◽  
Vol 72 (3) ◽  
pp. 201-216 ◽  
Author(s):  
P. M. Rutherford ◽  
N. G. Juma
Keyword(s):  
N Mineralization ◽  
Ecological Research ◽  
Clay Loam ◽  
Glucose Addition ◽  
Soil C ◽  
Carbon And Nitrogen ◽  
Soil C And N ◽  
C And N ◽  
Typic Cryoboroll ◽  
Bacterial C

Modelling in soil ecological research is a means of linking the dynamics of microbial and faunal populations to soil processes. The objectives of this study were (i) to simulate bacterial-protozoan interactions and flows of C and N in clay loam Orthic Black Chernozemic soil under laboratory condtions; and (ii) to quantify the flux of C and N (inputs and outputs) through various pools using the simulation model. The unique features of this model are: (i) it combines the food chain with specific soil C and N pools, and (ii) it simultaneously traces the flows of C, 14C, N and 15N. It was possible to produce a model that fitted the data observed for the soil. The simulated CO2-C evolved during the first 12 d was due mainly to glucose addition (171 μg C g−1 soil) and cycling of C in the soil (160 μg C g−1 soil). During this interval, bacterial C uptake was 5.5-fold greater than the initial bacterial C pool size. In the first 12 d protozoa directly increased total CO2-C evolution by 11% and increased NH4-N mineralization 3-fold, compared to soil containing only bacteria. Mineralization of C and N was rapid when bacterial numbers were increased as a result of glucose addition. Key words: Acanthamoeba sp., modelling, N mineralization-immobilization, organic matter, Pseudomonas sp., Typic Cryoboroll

Short-term effects of polyacrylamide and dicyandiamide on C and N mineralization in a sandy loam soil

2016 ◽  
Vol 32 (1) ◽  
pp. 127-136 ◽  
Author(s):  
C. Watson ◽  
Y. Singh ◽  
T. Iqbal ◽  
C. Knoblauch ◽  
P. Simon ◽  
...  
Keyword(s):  
N Mineralization ◽  
Sandy Loam ◽  
Sandy Loam Soil ◽  
Short Term ◽  
C And N Mineralization ◽  
Loam Soil ◽  
C And N ◽  
Short Term Effects

TOLERANCE OF EARLY-MATURING SOYBEAN CULTIVARS TO METRIBUZIN

1986 ◽  
Vol 66 (1) ◽  
pp. 125-130 ◽  
Author(s):  
G. H. FRIESEN ◽  
D. A. WALL
Keyword(s):  
Sandy Loam ◽  
Controlled Environment ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Soybean Cultivars ◽  
Early Maturing ◽  
Glycine Max L ◽  
Loam Soil ◽  
Environment Chamber ◽  
Chamber Studies

McCall, Maple Presto, Maple Amber and OT80-3 soybean (Glycine max (L.) Merr.) cultivars were evaluated under field conditions for their response to metribuzin. Maple Amber was found to be less tolerant than the other cultivars. In controlled environment chamber studies, injury to this cultivar was more severe on a sandy loam soil than on a clay loam soil. Fall applications of metribuzin, alone or tank-mixed with trifluralin, were tolerant to Maple Amber soybeans and such applications may offer a practical alternative to spring treatments for broad spectrum weed control in the less tolerant soybean cultivars grown in Manitoba.Key words: Metribuzin, trifluralin, preplant incorporation, fall treatments, soybean cultivars

scholarly journals Biochar Improves Plant Growth and Reduces Nutrient Leaching in Red Clay Loam and Sandy Loam

2012 ◽  
pp. 86-90 ◽  
Author(s):  
Kalpana Pudasaini ◽  
Nanjappa Ashwath ◽  
Kerry Walsh ◽  
Thakur Bhattarai
Keyword(s):  
Sandy Loam ◽  
Vegetable Production ◽  
Clay Loam ◽  
Plant Establishment ◽  
Clay Loam Soil ◽  
Red Clay ◽  
Green Waste ◽  
Loam Soil ◽  
Shoot Weight ◽  
Water Holding

A factorial pot experiment was conducted using two types of soils (sandy loam and red clay loam) that are commonly used for commercial vegetable production in Bundaberg, region of Central Queensl and Australia. The soils were amended with 0, 25, 50 and 75 t/ha of green waste biochar and minimum doses of N, P and K (30 kg/ha, 30 kg/ha and 40 kg/ha respectively). After two weeks of plant establishment, the pots were leached with 1.5 litres of deionised water at week intervals, and cation concentrations of the leachate were determined. In 25 t/ha biochar treatment, there was a significant (P<0.05) reduction in K and Ca leaching by 40% and 26% respectively from sandy loam, and of Ca by 23% from the red clay loam. Soil water holding capacity and soil organic carbon were also increased in both biochar treated soils. After 12 weeks of growth, shoot weight was signifi cantly (P<0.05) higher in 25 t/ha biochar-treated sandy loam and red clay loam (32% and 31% respectively). These results clearly demonstrated that a higher yield of capsicum can be achieved from green waste biochar application in sandy loam and red clay loam at 25 t/ha biochar.DOI: http://dx.doi.org/10.3126/hn.v11i1.7221 Hydro Nepal Special Issue: Conference Proceedings 2012 pp.86-90

Leaching and mobility of carbofuran from granular and alginate controlled release formulations

2000 ◽  
Vol 134 (4) ◽  
pp. 405-412 ◽  
Author(s):  
A. S. MAREI ◽  
H. R. SOLTAN ◽  
A. MOUSA ◽  
A. KHAMIS
Keyword(s):  
Controlled Release ◽  
Sandy Loam ◽  
Soil Column ◽  
Sandy Loam Soil ◽  
Flooded Soil ◽  
Clay Loam ◽  
Sandy Clay Loam ◽  
Sandy Clay ◽  
Controlled Release Formulations ◽  
Loam Soil

Controlled release (CR) formulations can significantly influence the fate of carbofuran in the environment. The influence of three alginate-encapsulated CR formulations compared with the granular formulation (G10%) on the mobility of carbofuran in sandy clay loam soil and sandy loam soil was investigated. In flooded soil the leaching potential of the three alginate controlled release formulations tested was decreased more than nine times (not more than 3%) compared with the G10% (28%). Most of the released carbofuran was confined to the top 0–5 cm of the soil column followed by the second 5–10 cm layer and the least was found in the fourth section (15–20 cm). The data obtained for a sandy loam soil irrigated by drip irrigation showed that the greatest proportion of carbofuran leached through the columns was from the G10% (52%) compared with 3–4% from CR formulations over a 30-day period. The carbofuran concentrations found in different soil depths showed similar trends to those for the flooded soil. Based on the residue levels recorded within the 20 cm depth, the relative retention ratio of carbofuran in sandy clay loam versus sandy loam soil was 1·2[ratio ]1 for the controlled release formulations and 1·9[ratio ]1 for the G10%.

scholarly journals Effect of growing media on mat type seedling raised for mechanical rice transplanting 

2018 ◽  
Vol 64 (No. 3) ◽  
pp. 157-167
Author(s):  
Hossen Anwar M ◽  
Hossain Mosharraf M ◽  
Haque Enamul M ◽  
Bell Richard W
Keyword(s):  
Rice Straw ◽  
Rice Bran ◽  
Sandy Loam ◽  
Organic Fertilizer ◽  
Poultry Litter ◽  
Cow Dung ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Loam Soil ◽  
Rolling Quality

Mechanical transplanted seedling must meet the requirements of standard seedling block with uniform distribution of seedlings and inter-twisting roots for rolling. This study was conducted to identify the effect of growing media on mat type seedling raised for mechanical transplanting at Bangladesh Rice Research Institute (BRRI), Gazipur during the period of 2012–2014 covering two dry and cold seasons (Boro) and one wet season (Aman). Seedling were raised on plastic tray using sandy loam and clay loam soil mixed with decomposed cow-dung, mustard cake, rice straw organic fertilizer, rice bran, poultry litter and vermicompost at the rate of 0.0, 10, 20, 30 and 40%. Rolling quality of the seedling mat decreased and seedling height increased with the increased of mixing rate of organic fertilizer except rice bran and mustard cake. Averaged across three seasons, 10 to 30% cow-dung, rice straw organic fertilizer, vermicompost, 10% poultry litter and 20 to 30% rice bran with both types of soil was found suitable for seedling mat and seedling height. However, seedling varied among the organic fertilizers with both types of soil in the order of cow-dung &gt; rice bran &gt; vermicompost &gt; poultry liter &gt; rice straw organic fertilizer &gt; mustard cake. Clay loam soil showed better performance on rolling quality over sandy loam soil.

Acetylene reduction by non-symbiotic bacteria in artificial soil aggregates amended with glucose

1974 ◽  
Vol 20 (6) ◽  
pp. 877-881 ◽  
Author(s):  
C. I. Mayfield ◽  
R. L. Aldworth
Keyword(s):  
Sandy Loam ◽  
Soil Aggregates ◽  
Peripheral Zone ◽  
Sandy Loam Soil ◽  
Artificial Soil ◽  
Clay Loam ◽  
Sandy Clay Loam ◽  
Sandy Clay ◽  
Loam Soil ◽  
Soil Activity

The C2H2-reduction assay was used to study the activity of non-symbiotic N2-fixing bacteria in glucose-amended artificial soil aggregates prepared from a sandy clay loam and a sandy loam soil. Anaerobic incubation under nitrogen resulted in significantly higher rates and greater total quantities of C2H2 reduction than did incubation in air. In the sandy clay loam soil activity under both incubation conditions was due to anaerobic N2-fixing bacteria, whereas in the sandy loam soil aerobic N2-fixing bacteria also proliferated in the aggregates. Direct observation of sectioned aggregates by fluorescence microscopy showed that peripheral zone 1 mm thick sup ported the growth of aerobic microorganisms. The anaerobic microsites in the interior of the aggregates were well protected since disruption procedures involving vigorous shaking with aerated water were required to allow O2 to penetrate and inhibit the anaerobic activity.

Effect of Commonly used Turfgrass Herbicides on Bermudagrass (Cynodon dactylon) Root Growth

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 641-647 ◽  
Author(s):  
Frederick M. Fishel ◽  
G. Euel Coats
Keyword(s):  
Root Growth ◽  
Sandy Loam ◽  
Sandy Loam Soil ◽  
Root Weight ◽  
Clay Loam ◽  
Soil Layers ◽  
Sandy Clay Loam ◽  
Fine Sandy Loam ◽  
Sandy Clay ◽  
Loam Soil

Experiments were conducted in 1990 and 1991 to determine bioavailability of PRE herbicides at three soil profile depths and two soil types in established common bermudagrass sods. Prodiamine and oryzalin reduced ‘Tifgreen’ bermudagrass root growth in the 5- to 7.5-cm layer of a Bosket very fine sandy loam soil at 2 and 4 wk after treatment in 1991. These herbicides decreased bermudagrass root weight in both the Bosket and Marietta sandy clay loam both years in samples taken from the 2.5- to 5-cm depth layer. In the 0- to 2.5-cm soil layer, all herbicides reduced root weight in 1990. In a bioassay, prodiamine caused decreased Tifgreen bermudagrass root growth at concentrations as low as 4 ppb by wt in the very fine sandy loam soil, while 8 ppb was necessary in the sandy clay loam soil. Prodiamine was detected in the very fine sandy loam at 4 wk after treatment at all depths in 1991 (65, 45, and 39 ppb in the 0- to 2.5-, 2.5- to 5-, and 5- to 7.5-cm soil layers, respectively). Oryzalin was also detected at all depths in 1991 when sampled at 2 and 4 wk after treatment in the very fine sandy loam. Pendimethalin was present in concentrations of 38, 39, and 37 ppb in the sandy clay loam at 2 wk after treatment in the 0- to 2.5-, 2.5- to 5-, and the 5- to 7.5-cm soil layers, respectively. Pendimethalin was also detected in the very fine sandy loam at 2 wk after treatment at concentrations of 55, 69, and 36 ppb in the 0- to 2.5-, 2.5- to 5-, and 5- to 7.5-cm soil layers, respectively.

Root Growth and Yield Response of Rainfed Lowland Rice to Planting Method

1987 ◽  
Vol 23 (3) ◽  
pp. 305-313 ◽  
Author(s):  
P. K. Sharma ◽  
S. K. De Datta ◽  
C. A. Redulla
Keyword(s):  
Root Growth ◽  
Grain Yield ◽  
Water Table ◽  
Sandy Loam ◽  
Lowland Rice ◽  
Yield Response ◽  
Clay Loam ◽  
Transplanted Rice ◽  
Rainfed Lowland ◽  
Loam Soil

SUMMARYField experiments were conducted on two soils (clay loam and sandy loam) with varying texture and water table depth to study the effects of two planting methods (dry seeding and transplanting) on the root growth and grain yield of rainfed lowland rice. About 75% of the roots were found in the top 10 cm soil. Root length density at the flowering stage and grain yield in the sandy loam soil, with a water table deeper than 1.5 m, were less in dry-seeded than in transplanted rice, probably because of the greater moisture stress in dry-seeded rice between late tillering and harvest. In the clay loam soil, with the water table mostly at the soil surface, there was no difference in grain yield between dry-seeded and transplanted rice.

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