EFFECT OF SOIL WATER STATUS AND STRENGTH ON TRAFFICABILITY

1979 ◽  
Vol 59 (3) ◽  
pp. 313-324 ◽  
Author(s):  
C. L. PAUL ◽  
J. DE VRIES

Trafficability tests with typical farm vehicles were carried out on three lowland fields at various degrees of wetness. Structural damage after the first and third passes was assessed in terms of bulk density, aeration porosity, pore-size distribution and rut depth. These indices could not be used per se as criteria for trafficable conditions because of lack of information concerning their relationship to plant growth. Instead, a trafficability criterion oriented toward traction efficiency was established by determining for each soil the relationship between its strength (assessed with a cone penetrometer) and traction efficiency measured by wheelslip. A critical value of strength for trafficability was inferred from this relationship. This was then used to obtain soil water tension limits for trafficability from known relations between tension and strength. Soil strength was found to be linearly dependent upon water table depth in spring when evapotranspiration was small and when the water table depth was less than 80 cm. Consideration of these relationships led to the establishment of critical water table limits for trafficability. These were 53, 45, and 60 cm for Lumbum muck, Hallart silty clay loam (SiCL) (grassland), and Hallart silty clay loam (cultivated), respectively.

2015 ◽  
Vol 22 (4) ◽  
pp. 589-609 ◽  
Author(s):  
Chi Xu ◽  
Wen-Zhi Zeng ◽  
Jing-Wei Wu ◽  
Jie-Sheng Huang

Abstract Intermittent irrigation has attracted much attention as a water-saving technology in arid and semi-arid regions. For understanding the effect of intermittent irrigation on water and solute storage varied from irrigation amount per time (IRA), irrigation application frequency (IRAF), irrigation intervals (IRI) and even soil texture (ST), intermittent irrigation experiment was carried out in 33 micro-plots in Inner Mongolia, China. The experiment results were used for the calibration and validation of HYDRUS-1D software. Then 3 ST (silty clay loam, silty loam, and silty clay), 5 IRA (2, 4, 6, 8, and 10 cm), 4 IRAF (2, 3, 4, and 5 times) and 4 IRI (1, 2, 3, and 4 days) were combined and total 240 scenarios were simulated by HYDRUS-1D. Analysis of variance (ANVOA) of simulated results indicated that ST, IRA, and IRAF had significant effect on salt and nitrate nitrogen (NO3−-N) storage of 0-40 cm depth soil in intermittent irrigation while only ST affected soil water storage obviously. Furthermore, salt leaching percentage (SLP) and water use efficiency (WUE) of 0-40 cm depth were calculated and statistical prediction models for SLP were established based on the ANOVA using multiple regression analysis in each soil texture. Then constraint conditions of soil water storage (around field capacity), salt storage (smaller than 168 mg·cm−2), WUE (as large as possible) in 0-40 cm depth and total irrigation water amount (less than 25 cm) were proposed to find out the optimal intermittent irrigation strategies. Before sowing, the optimal irrigation strategy for silty clay loam soil was 6 cm IRA, 3 times IRAF, and 2 days IRI respectively. For silty loam and silty clay soils, IRA, IRAF, and IRI were 8 cm, 3 times, and 2 days respectively.


1985 ◽  
Vol 104 (2) ◽  
pp. 303-307
Author(s):  
P. K. Sharma ◽  
A. K. Sinha ◽  
T. N. Chaudhaby

SummaryUpward flux of water and deep-placed (8–10 cm) P was studied in columns of sandyloam and silty clay loam, with water tables of 60 and 90 cm, each subjected to potential evaporation rates of 2–2 and 7–5 mm/day, for 15 days. An amount of 300 mg P/kg soil, labelled with 20 /tCi 32P/g P, was applied as diammonium hydrogen orthophosphate.Evaporation losses increased with increase in potential evaporation (PE) and decrease in depth to water table in both soils, but the ratio of actual to potential evaporation (AE/PE) decreased with increasing PE, indicating that the evaporative losses in both the soils were mainly controlled by their hydraulic conductive properties. Under no circumstances did AE equal PE. Evaporation, in general, was higher from sandy loam than from silty clay loam.Corresponding to water flux, total upward P flux increased with increasing PE and decreasing depth to water. In the sandy loam, with 2–2 mm PE/day, 21 % of the deepplaced P moved to the soil surface with the 60 cm water table, against 5 % with the 90 cm water table. Under 7–5 mm PE/day, 39% P migrated to the surface with the 60 cm water table, but no 3aP was detected at the surface with the 90 cm water table. In the silty clay loam, however, P movement was much restricted.


2021 ◽  
Author(s):  
T. L. Dirwai ◽  
A. Senzanje ◽  
T. Mabhaudhi

Abstract We developed an empirical soil wetting geometry model for silty clay loam and coarse sand soils under a semi-permeable porous wall line source Moistube Irrigation (MTI) lateral irrigation. The model was developed to simulate vertical and lateral soil water movement using the Buckingham pi (π) theorem. This study was premised on a hypothesis that soil hydraulic properties influence soil water movement under MTI. Two independent, but similar experiments, were conducted to calibrate and validate the model using MTI lateral placed at a depth of 0.2 m below the soil surface in a soil bin with a continuous water supply (150 kPa). Soil water content was measured every 5 minutes for 100 h using MPS-2 sensors. Model calibration showed that soil texture influenced water movement (\(p\) < 0.05) and showed a good fit for wetted widths and depths for both soils ( \(nRMSE\) = 0.5% − 10%; \(NSE \ge\) 0.50; and d-index \(\ge\) 0.50. The percentage bias \(\left(PBIAS\right)\) statistic revealed that the models’ under-estimated wetted depth after 24 h by 21.9% and 3.9% for silty clay loam and sandy soil respectively. Sensitivity analysis revealed an agreeable models’ performance values. This implies the applicability of the model for estimating wetted distances for an MTI lateral placed at 0.2 m. However, further experimentation under varying scenarios for which MTI would be used, including field conditions, is needed to further validate the model and establish robustness. MTI wetting geometry informs placement depth for optimal irrigation water usage.


1983 ◽  
Vol 63 (1) ◽  
pp. 27-35 ◽  
Author(s):  
C. L. PAUL ◽  
J. DE VRIES

Effects of subsurface drainage on trafficability of farmland were assessed over a 2-yr period. When compared with undrained land, drainage by drains spaced at 30.5 m resulted in earlier trafficability by 2–4 wk in a silty clay loam and by up to 5 wk in a muck. Halving the spacing did not increase benefits. Drainage intensity exerted its greatest influence on trafficability when the intensity was low, that is, at large drain spacings. Prediction of trafficability by two procedures revealed close agreement with one another and compared extremely well with dates on which measured water table depth and soil water tension were considered by farmers to be adequate for trafficability. Key words: Trafficability prediction, subsurface drainage, drain spacing, drainage intensity


Author(s):  
Mohammed Aajmi Salman ◽  
Jawad A. Kamal Al-Shibani

Beneficial microorganisms play a key role in the availability of ions minerals in the soil and use Randomized Complete Block Desing ( R.C.B.D ). The objective of this paper to the study effect of the of biofertilizer and miniral treatments on availability of NPK for crop corn zea mays L.Two types of biofertilizer are Bacterial Bacillus subtilis and Fungal Trichoderma harianum. Three levels of potassium fertilizer are (2.9533, 0.4000 and 2.9533). A field experiment in fall season of 2018 Has been conducted in silty clay loam soil. The experimental Results indicated that Bacillus and Trichoderma inoculation separately or together Have made a significant effect to increase in the availability of N P K in the soil compare to other treatments. The grain yield is where (2.9533, 0.4000 and 2.9533) of bacterial and fungal bio-fertilizer and potassium fertilizers respectively as compared to the control.


2021 ◽  
Vol 70 (1) ◽  
pp. 27-40
Author(s):  
Yaung Kwee ◽  
Khin Soe

In this study, two sites from tea and apple growing sites were collected from Pyay village and Nine Mile village, Mindat district, Chin state of West Myanmar under a humid subtropical climate. The results of physicochemical properties of observed soils were neutral pH, favorable moisture, silty clay loam texture, very high content of organic carbon, organic matter and total nitrogen. However, the tea growing soil was very poor in phosphorus and potassium content. Moreover, both soils lack of available potassium. The content of heavy metals in both soils was not varied from each other and followed the order: Fe (iron) > Cu (copper) >Zn (zinc) > Pb (lead) > Cr (chromium) and was below the maximum allowed concentrations (MAC). Therefore, the studied soils are generally favorable for cultivation under the condition of application of phosphorus and potassium fertilizers. However, due to the regular application of fertilizers and pesticides, it is necessary to monitor these soils for PTE levels. Further research is recommended, which must include analyses of the physicochemical properties of soils to a two depths of 0-30 and 30-60 cm, especially for the area where fruit plants are grown. In addition, higher density of soil samples and sub-samples are necessary to produce a reliable dataset that will allow proper statistical analysis.


Author(s):  
Abdulmahdi S.ALansari ◽  
Muhammad M.Yassin ◽  
Mahdi W.Seheib

This study was conducted to evaluation the role of the organic acids in the phosphorus fractions in silty clay loam texture. The laboratoryexperiment was conducted by adding the organic acids (Humic acid ,Citric acid ,Oxalic acid , Malic acid ,Acetic acid and Lactic acid )to the fertilized soil with conc. super phosphate fertilizer with 100 kg h-1 level with concentrations (0,15,30,45 and60)mg L-1,except Humic acid (500,1000,1500 and 2000) mg L-1.The soil was incubated at 30 C for 14,28,42,56 and 70 days period and the keep of field capacity about of incubation period during the daily weight.Amount of available ,mineral ,organic and total phosphorus after each incubated period were measured. The results showed that theaddition of organic acids of Humic acid ,Citric acid ,Oxalic acid and Malic acid were caused to increaseamount of available ,mineral ,organic and constant of total phosphorus in fertilized soil with conc. super phosphate fertilizer and increased its amount with increasing of organic acid concentration and better of Humic acid 2000mg L-1 significanton all the treatments .The results of the study that theaddition of organic acids were caused to increase amount of available and mineral phosphorus with increasing of incubation period and constant amount of total phosphorus and decreasing of organic phosphorus amount and available for only soil and only fertilizer treatment during increasing of incubation period .The organic acids can be arranged according to its ability toincrease the availabilityof the phosphorus as follow :


2008 ◽  
Vol 88 (1) ◽  
pp. 85-97 ◽  
Author(s):  
Hafida Zaher ◽  
Jean Caron

The slaking process after rapid wetting is a key factor controlling soil structural stability in dry soil, and an understanding of the relative importance of the different mechanisms involved in slaking may help in the design of management strategies aimed at maintaining a stable surface soil structure. Slaking has been linked to, among other factors, rapid pressure build-up in aggregate, and previous work has emphasized the role of organic matter to hamper that pressure build-up, possibly due to hydrophobicity, reducing rapid water entry within aggregates and hence the build-up. This study emphasizes this latter aspect linked to slaking. The evolution of the intra-aggregate pressure, the matter lost by slaking and the expelled air after rapid wetting of two soils of different textures (clay loam soil and silty-clay loam soil) amended with different types of paper sludge were studied. Hydrophobicity effects were also studied using a tensio-active solution. The results of these experiments showed that when aggregates were submitted to sudden wetting, those treated with paper sludge had an improved resistance to the destructive action of rapid wetting. The lower pressures measured in the aggregates from the amended soils and having less slaking resulted most likely from slow water entry and reduced swelling. Detailed investigation on the link between hydrophobicity and water entry revealed that the true hydrophobic effect (modification of contact angle) was non-existent for the silty-clay loam and minor for the clay loam. This study, rather, suggests that changes in the water potential at the wetting front following organic matter addition and aggregate immersion most likely depend on pore occlusion and on changes in pore surface roughness. Key words: Aggregate stability, organic matter, slaking, pressure, swelling, wettability


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