Assessing tillage- and cropping-induced changes in relative conductivity

Soil Research ◽  
1998 ◽  
Vol 36 (5) ◽  
pp. 799
Author(s):  
V. Rasiah

Although changes in relative hydraulic conductivity(Krc) in the surface soil layer can have significantimpact on transport of water and solutes below this layer, experimentaldetermination of Krc is laborious and expensive. In thisstudy, a simple theoretical equation has been used to compute near-surfaceKrc and assess its sensitivity to tillage- andcropping-induced near-surface changes in soil porosity (.epsi;), porecontinuity (PC), and soil water content (θ). The data were collected in1994 from a cropping and tillage system experiment established in 1988 on asilt loam soil. The tillage treatments were conventional and no-till. Thecropping treatments were continuous corn (Zea maize L.)under conventional cultivation (CT corn), corn following forages(alfalfa,Medicago sativa L.; and bromegrass,Bromus inermis L.) under conventional and no-till (NTcorn) practices, and continuous no-till corn. Soil bulk density (r ) and inthe near surface (depth, 0-2 ·5 cm) soil layer were measured in lateJuly 1994 subsequent to changes in tillage and cropping practices in May 1994.Only tillage differences had significant influence on ρ, θ, fractaldimension (D), PC, and Krc of the near-surface soillayer. A switch from no-till forages to CT corn resulted in increases in andD, and decreases in ρ , θ, and Krc. Theintroduction of NT corn into forage-terminated plots did not producesignificant changes in the above properties compared with continuous NT corn(7 years old), which was characterised by smaller values of and PC, and highθ and Krc. Water content, , and PC accounted for96% of the variability in Krc. The results showedthat the near-surface changes in Krc can be predictedwith high accuracy using the data on only ρ and θ which are easy togather.

1977 ◽  
Vol 57 (2) ◽  
pp. 81-91 ◽  
Author(s):  
C. W. LINDWALL ◽  
D. T. ANDERSON

The effectiveness of several commercial seeders and an experimental triple-disc press drill was assessed on a silt loam soil at Lethbridge over a 7-yr period on fields receiving chemical weed control instead of tillage between crops. The double- and triple-disc press drills generally failed to penetrate untilled surfaces adequately when soil bulk density in the upper 5 cm exceeded about 1.2 g/cm3 or when the quantity of surface residue exceeded about 3,700 kg/ha. Hoe openers penetrated the soil but failed to clear heavy residues when stubble and straw lengths were excessive (> 25 cm). In 2 of the 7 yr, yields of spring wheat (Triticum aestivum L.) on small plots seeded with the double- and triple-disc drills were superior to those seeded with the wide-spaced hoe drill (1,159 vs. 721 kg/ha in 1969, and 667 vs. 573 kg/ha in 1973). Yield differences were primarily due to wild oats (Avena fatua L.), which germinated because of the tillage action of hoe openers, in ridge areas between rows and which, despite the use of herbicides, seriously reduced yields from wide-spaced rows (23 and 36 cm). In the other years, yields were similar for all seeding methods. On 0.4-ha chemical fallow fields, yields were up to 51% lower within sprayer wheel traffic areas (bulk densities of 1.2 g/cm3 or greater in the 0- to 5-cm soil layer) because of shallow seed placement when double-disc drills were used but not when hoe drills were used.


2018 ◽  
Vol 98 (4) ◽  
pp. 738-742 ◽  
Author(s):  
L.L. Van Eerd ◽  
A.H. DeBruyn ◽  
L. Ouellette ◽  
D.C. Hooker ◽  
D.E. Robinson

Automated wet-sieving is preferred for this clay loam soil due to better sensitivity and savings (time and disposables) despite a larger capital investment. Rotations with greater frequency of winter wheat and no-till compared with conventional plow system had greater wet aggregate stability values, indicating better surface soil quality.


2019 ◽  
Vol 15 (No. 1) ◽  
pp. 47-54 ◽  
Author(s):  
Mxolisi Mtyobile ◽  
Lindah Muzangwa ◽  
Pearson Nyari Stephano Mnkeni

The effects of tillage and crop rotation on the soil carbon, the soil bulk density, the porosity and the soil water content were evaluated during the 6<sup>th</sup> season of an on-going field trial at the University of Fort Hare Farm (UFH), South Africa. Two tillage systems; conventional tillage (CT) and no-till and crop rotations; maize (Zea mays L.)-fallow-maize (MFM), maize-fallow-soybean (Glycine max L.) (MFS); maize-wheat (Triticum aestivum L.)-maize (MWM) and  maize-wheat-soybean (MWS) were evaluated. The field experiment was a 2 × 4 factorial, laid out in a randomised complete design. The crop residues were retained for the no-till plots and incorporated for the CT plots, after each cropping season. No significant effects (P &gt; 0.05) of the tillage and crop rotation on the bulk density were observed. However, the values ranged from 1.32 to1.37 g/cm<sup>3</sup>. Significant interaction effects of the tillage and crop rotation were observed on the soil porosity (P &lt; 0.01) and the soil water content (P &lt; 0.05). The porosity for the MFM and the MWS, was higher under the CT whereas for the MWM and the MWS, it was higher under the no-till. However, the greatest porosity was under the MWS. Whilst the no-till significantly increased (P &lt; 0.05) the soil water content compared to the CT; the greatest soil water content was observed when the no-till was combined with the MWM rotations. The soil organic carbon (SOC) was increased more (P &lt; 0.05) by the no-till than the CT, and the MFM consistently had the least SOC compared with the rest of the crop rotations, at all the sampling depths (0–5, 5–10 and 10–20 cm). The soil bulk density negatively correlated with the soil porosity and the soil water content, whereas the porosity positively correlated with the soil water content. The study concluded that the crop rotations, the MWM and the MWS under the no-till coupled with the residue retention improved the soil porosity and the soil water content levels the most.


Weed Science ◽  
1991 ◽  
Vol 39 (2) ◽  
pp. 200-203 ◽  
Author(s):  
Douglas D. Buhler ◽  
Thomas C. Mester

The effect of tillage systems on depth of emergence and densities of giant and green foxtail under different environmental and cropping conditions were evaluated from 1985 to 1987 at Arlington, Hancock, and Janesville, WI. Mean emergence depths in no-till were the shallowest, followed by chisel plow and conventional tillage at each location. At least 40% of the giant and green foxtail plants emerged from the upper 1 cm of soil in no-till compared to about 25% in chisel plow and less than 15% in conventional tillage. As many as 25% of the plants emerged from greater than 4 cm in conventional tillage compared to about 10% in chisel plow and less than 5% in no-till. Seedlings emerged from greater depths in a loamy sand than in a silt loam soil regardless of tillage system. At Arlington, green foxtail was the dominant species in conventional tillage, while giant foxtail dominated in chisel plow and no-till. Foxtail densities were greater in chisel plow and no-till than in conventional tillage at all three locations.


2004 ◽  
Vol 52 (3) ◽  
pp. 211-220 ◽  
Author(s):  
P. László ◽  
C. Gyuricza

Within the framework of cooperation between Szent István University and the Vienna University of Agricultural Sciences, a soil cultivation experiment in a maize (Zea mays L.) monoculture was set up for the first time in Austria near Pyhra (Lower Austria) in 1996. A study was conducted to evaluate the effects of ridge tillage (RT) in comparison with conventional mouldboard ploughing in autumn (CT) and no-tillage (NT) on the penetration resistance (PR), soil bulk density (BD) and porosity (P) of sandy loam soil (Typic Agriudoll). Analyses were made for each treatment and for different parts of the ridge (top and side of the ridge, and interrow) in 1998, 2000 and 2002. The average PR and BD values were greatest in the no-tillage plot, being 3.42 MPa and 1.56 g·cm-3, respectively. After six years, ridge tillage resulted in lower penetration resistance and bulk density values in the upper 20 cm than conventional tillage and no-tillage. Ridge tillage appears capable of reducing compaction in this soil. It can be concluded from the results that ridge tillage is capable of maintaining and improving favourable physical conditions in the soil.


1987 ◽  
Vol 67 (4) ◽  
pp. 905-917 ◽  
Author(s):  
K. C. WIRES ◽  
W. D. ZEBCHUK ◽  
G. C. TOPP

Shrinkage and volumetric water content of undisturbed soil cores 150 mm diam. × 100 mm high from four horizons of a silt-loam, Orthic Humic Gleysol were monitored throughout a drying cycle from saturation to oven dryness. Drying from saturation to − 100 kPa was by desorption apparatus. Subsequently the cores were subjected to controlled air drying and finally oven drying. The volume change, relative to the volume at saturation, of each core was monitored at 20 different water contents on the desorption curve, by measuring the X, Y and Z positions of 92 pins inserted in the top of each core. Total shrinkage values expressed as percentages of the cores' saturated volumes were Ap −23.4%, Bg −7.0%, BCg −11.8% and Cg −12.9%. The influence of soil structure on soil shrinkage was analyzed and the results were inconclusive because there appeared to be a complex interaction between ped size and the scale of measurement for shrinkage. Water loss during drying was partitioned between that replaced by air and that associated with pore volume reduction. For the Ap horizon from 0 to 1500 kPa, the proportions were 62% and 38% respectively. The results show clearly the dependence of soil bulk density and porosity on water potential and reinforce the contention that for comparison purposes bulk density and porosity must be expressed at a reference water content or potential. Key words: Shrinkage, pore volume, bulk density, undisturbed samples


2011 ◽  
Vol 47 (1) ◽  
pp. 111-136 ◽  
Author(s):  
EIHAB M. FATHELRAHMAN ◽  
JAMES C. ASCOUGH ◽  
DANA L. HOAG ◽  
ROBERT W. MALONE ◽  
PHILIP HEILMAN ◽  
...  

SUMMARYThere are many reasons why agricultural researchers carefully evaluate approaches to experimental data analysis. Agricultural experiments are typically highly complex, with many types of variables often collected at a wide range of temporal and spatial scales. Furthermore, research in the developing world is often conducted on-farm where simple and conventional experimental designs are often unsuitable. Recently, a variant of stochastic dominance called stochastic efficiency with respect to a function (SERF) has been developed and used to analyse long-term experimental data. Unlike traditional stochastic dominance approaches, SERF uses the concept of certainty equivalents (CEs) to rank a set of risk-efficient alternatives instead of finding a subset of dominated alternatives. This study evaluates the efficacy of the SERF methodology for analysing conventional and conservation tillage systems using 14 years (1990–2003) of economic budget data collected from 36 experimental plots at the Iowa State University Northeast Research Station near Nashua, IA, USA. Specifically, the SERF approach is used to examine which of two different tillage systems (chisel plough and no-till) on continuous corn (Zea mays) and corn/soyabean (Glycine max) rotation cropping systems are the most risk-efficient in terms of maximizing economic profitability (gross margin and net return) by crop across a range of risk aversion preferences. In addition to the SERF analysis, we also conduct an economic analysis of the tillage system alternatives using mean-standard deviation and coefficient of variation for ranking purposes. Decision criteria analysis of the economic measures alone provided somewhat contradictive and non-conclusive rankings, e.g. examination of the decision criteria results for gross margin and net return showed that different tillage system alternatives were the highest ranked depending on the criterion and the cropping system (e.g. individual or rotation). SERF analysis results for the tillage systems were also dependent on the cropping system (individual, rotation or whole-farm combined) and economic outcome of interest (gross margin or net return) but only marginally on the level of risk aversion. For the individual cropping systems (continuous corn, rotation corn and rotation soyabean), the no-till tillage and rotation soyabean system was the most preferred and the chisel plough tillage and continuous corn system the least preferred across the entire range of risk aversion for both gross margin and net return. The no-till tillage system was preferred to the chisel plough tillage system when ranking within the continuous corn and the corn-soyabean rotation cropping systems for both gross margin and net return. Finally, when analysing the tillage system alternatives on a whole-farm basis (i.e. combined continuous corn and corn-soybean rotation), the no-till tillage system was clearly preferred to the chisel plough tillage system for both gross margin and net return. This study indicates that the SERF method appears to be a useful and easily understood tool to assist farm managers, experimental researchers and, potentially, policy makers and advisers on problems involving agricultural risk.


2010 ◽  
Vol 34 (1) ◽  
pp. 211-2178 ◽  
Author(s):  
Fabiana de Souza Pereira ◽  
Itamar Andrioli ◽  
Amauri Nelson Beutler ◽  
Cinara Xavier de Almeida ◽  
Faber de Souza Pereira

The intensive use of land alters the distribution of the pore size which imparts consequences on the soil physical quality. The Least Limiting Water Range (LLWR) allows for the visualization of the effects of management systems upon either the improvement or the degradation of the soil physical quality. The objective of this study was to evaluate the physical quality of a Red Latosol (Oxisol) submited to cover crops in the period prior to the maize crop in a no-tillage and conventional tillage system, using porosity, soil bulk density and the LLWR as attributes. The treatments were: conventional tillage (CT) and a no-tillage system with the following cover crops: sunn hemp (Crotalaria juncea L.) (NS), pearl millet (Pennisetum americanum (L.) Leeke) (NP) and lablab (Dolichos lablab L.) (NL). The experimental design was randomized blocks in subdivided plots with six replications, with the plots being constituted by the treatments and the subplots by the layers analyzed. The no-tillage systems showed higher total porosity and soil organic matter at the 0-0.5 m layer for the CT. The CT did not differ from the NL or NS in relation to macroporosity. The NP showed the greater porosity, while CT and NS presented lower soil bulk density. No < 10 % airing porosity was found for the treatments evaluated, and value for water content where soil aeration is critical (θPA) was found above estimated water content at field capacity (θFC) for all densities. Critical soil bulk density was of 1.36 and 1.43 Mg m-3 for NP and CT, respectively. The LLWR in the no-tillage systems was limited in the upper part by the θFC, and in the bottom part, by the water content from which soil resistance to penetration is limiting (θPR). By means of LLWR it was observed that the soil presented good physical quality.


2020 ◽  
Vol 19 ◽  
pp. 13
Author(s):  
RANIER VIEIRA FERREIRA ◽  
ROSE LUIZA MORAES TAVARES ◽  
SILVIO VASCONCELOS PAIVA FILLHO ◽  
INDIAMARA MARASCA ◽  
ALESSANDRO GUERRA SILVA

In the central region of Brazil, sorghum and maize are considered viable crop alternatives to be cultivated during off-season periods, mainly for the production of grains in succession to the cultivation of soybeans and intercropping with brachiaria grasses. This study aimed to evaluate the physical soil qualities of the soil from an area with different off-season management histories (monoculture or agricultural intercropping). Maize, sorghum and brachiaria crops have been cultivated under no-tillage system. The experiment was conducted using a randomized complete block design, with four replications. The treatments included: monoculture or intercropping between sorghum and brachiaria (first off-season strategy) or maize and brachiaria (second off-season strategy). The following physical properties of the soil were evaluated: soil bulk density, porosity, soil resistance to penetration, soil moisture and texture and the contents of organic carbon, which were analyzed at 0-20, 20-40 and 40-60 cm deep. In the off-season, the cultivation of single brachiaria promoted a greater amount of dry matter when compared with sorghum- brachiaria or maize-brachiaria intercropping. The topsoil presented better physical quality when compared with the adjacent layers under no-tillage system. The use of brachiaria combined with sorghum or maize tends to improve the macro and microporosity of the soil.


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