Soil fertility changes in the long-term experimental plots at Kybybolite, South Australia. IV. Changes in certain moisture characteristics

1964 ◽  
Vol 15 (1) ◽  
pp. 91 ◽  
Author(s):  
JS Russell ◽  
RC Shearer
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Plant Growth ◽  
Soil Fertility ◽  
Surface Soil ◽  
South Australia ◽  
Water Capacity ◽  
Available Water Capacity ◽  
Experimental Plots

A study of soils from various pasture treatments at Kybybolite has shown that changes in soil moisture characteristics have occurred in association with increases in organic matter. The 15 atmospheres (atm), 0.33 atm, and available water capacity (A.W.C.) values have all shown increases which can be related to organic matter changes. The largest increase has occurred in soil moisture-holding capacity (0.33 atm). Less than half of this increase, however, is available for plant growth, owing to corresponding increases in 15 atm values. Calculations of A.W.C. in terms of depth of soil water has shown that the magnitude of the change has been relatively small in relation to the large increases in organic matter. The results indicate that the scope for substantially increasing A.W.C. in coarse-textured soils by pasture improvement is limited. Possible beneficial and deleterious effects on plant growth due to observed changes in moisture characteristics of the surface soil are discussed.

Soil Management: An Overview

2003 ◽  
Author(s):  
Anthony S. R. Juo ◽  
Kathrin Franzluebbers
Keyword(s):  
Organic Matter ◽  
Soil Moisture ◽  
Soil Organic Matter ◽  
Soil Fertility ◽  
Crop Yield ◽  
Surface Soil ◽  
Soil Management ◽  
Compacted Soils ◽  
Slash And Burn ◽  
Over Time

The term “soil management” refers to the human manipulation of chemical, physical, and biological conditions of the soil for the production of agricultural plants. Good soil management helps maintain and improve soil fertility while sustaining optimum crop yield over time, whereas inappropriate soil management practices can lead to the degradation of soil fertility and a declining crop yield within a relatively short period of time. In a cropped field, where pests and disease are not limiting factors, the decline in crop yield over time may be attributed to several soil-related factors, namely, deterioration of soil physical conditions, such as surface crusting and subsurface compaction, depletion of available nutrients in the soil and soil acidification, soil moisture stress (drought or waterlogging), and the decline in soil organic matter and soil biological activity. Thus, major tasks of soil management for crop production include the following: • tillage and seedbed preparation • replenishment of soil nutrients • soil moisture management • maintenance of soil organic matter The main purposes of tillage are to loosen a compacted surface soil to facilitate seed emergence and root growth through improved soil aeration and water storage, and to eradicate weeds before planting and control subsequent weed growth during the cropping season. Common tillage practices used in tropical agriculture are as follows: • Slash-and-burn, followed by sowing seeds into holes made by punching a wooden stick into the porous surface soil. • Slash-and-burn, followed by heaping or ridging the compacted surface soil using a hand hoe. • Plowing, harrowing, and puddling in irrigated rice paddies using water buffalo or a two-wheel power-tiller. • Ridge tillage using a hand hoe, animal traction or an engine-powered tractor on crusted or compacted soils and poorly drained clayey soils. • Minimum or strip tillage with a crop-residue mulch on coarse-textured soils and on sloping land. • Conventional tillage involving plowing and harrowing on fine-textured soils and compacted soils on flatland. • Minimum tillage with a plant-residue mulch or cover crop in annual and tree crop mixed systems (agroforestry).

scholarly journals Determination of the effects of tillage on the productivity of a sandy loam soil using soil productivity models

2021 ◽  
Vol 67 (No. 3) ◽  
pp. 108-115
Author(s):  
Tanko Bako ◽  
Ezekiel Ambo Mamai ◽  
Istifanus Akila Bardey
Keyword(s):  
Organic Matter ◽  
Iron Oxide ◽  
Bulk Density ◽  
Aluminium Oxide ◽  
Available Phosphorus ◽  
Soil Productivity ◽  
Water Capacity ◽  
Available Water ◽  
Available Water Capacity ◽  
Tillage Methods

Based on the hypothesis that soil properties and productivity components should be affected by different tillage methods, field and laboratory experiments were conducted to study the effects of zero tillage (ZT), one pass of disc plough tillage (P), one pass of disc plough plus one pass of disc harrow tillage (PH) and one pass of disc plough plus two passes of disc harrow tillage (PHH) on the distribution of the bulk density, available water capacity, pH, organic matter, available phosphorus, iron oxide and aluminium oxide at different soil depths, and their effects on the soil productivity. The available water capacity, pH, organic matter and available phosphorus were found to increase with the degree of tillage, while the bulk density, iron oxide and aluminium oxide were found to decrease with the degree of tillage. The results show that the soil productivity index was significantly (P ≤ 0.05) affected by the tillage methods and found to increase with the degree of tillage.

Concurrent and antecedent soil moisture relate positively or negatively to probability of large wildfires depending on season

2016 ◽  
Vol 25 (6) ◽  
pp. 657 ◽  
Author(s):  
Erik S. Krueger ◽  
Tyson E. Ochsner ◽  
J. D. Carlson ◽  
David M. Engle ◽  
Dirac Twidwell ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Growing Season ◽  
Fuel Moisture ◽  
Fuel Production ◽  
Antecedent Soil Moisture ◽  
Plant Water Stress ◽  
Wildfire Occurrence ◽  
Water Capacity ◽  
Available Water Capacity ◽  
Dormant Season

Measured soil moisture data may improve wildfire probability assessments because soil moisture is physically linked to fuel production and live fuel moisture, yet models characterising soil moisture–wildfire relationships have not been developed. We therefore described the relationships between measured soil moisture (concurrent and antecedent), as fraction of available water capacity (FAW), and large (≥405 ha) wildfire occurrence during the growing (May–October) and dormant (November–April) seasons from 2000 to 2012 in Oklahoma, USA. Wildfires were predominantly grass and brush fires but occurred across multiple fuel types including forests. Below-average FAW coincided with high wildfire occurrence each season. Wildfire probability during the growing season was 0.18 when concurrent FAW was 0.5 (a threshold for plant water stress) but was 0.60 when concurrent FAW was 0.2 (extreme drought). Dormant season wildfire probability was influenced not only by concurrent but also by antecedent FAW. Dormant season wildfire probability was 0.29 and 0.09 when FAW during the previous growing season was 0.9 (near ideal for plant growth) and 0.2, respectively. Therefore, although a wet growing season coincided with reduced wildfire probability that season, it also coincided with increased wildfire probability the following dormant season, suggesting that the mechanisms by which soil moisture influences wildfire probability are seasonally dependent.

scholarly journals Short-Term and Long-Term Surface Soil Moisture Memory Time Scales Are Spatially Anticorrelated at Global Scales

2019 ◽  
Vol 20 (6) ◽  
pp. 1165-1182 ◽  
Author(s):  
Kaighin A. McColl ◽  
Qing He ◽  
Hui Lu ◽  
Dara Entekhabi
Keyword(s):  
Soil Moisture ◽  
Time Scales ◽  
Time Scale ◽  
Surface Soil ◽  
Satellite Observations ◽  
Surface Soil Moisture ◽  
Short Term ◽  
Term Memory ◽  
Memory Time

Abstract Land–atmosphere feedbacks occurring on daily to weekly time scales can magnify the intensity and duration of extreme weather events, such as droughts, heat waves, and convective storms. For such feedbacks to occur, the coupled land–atmosphere system must exhibit sufficient memory of soil moisture anomalies associated with the extreme event. The soil moisture autocorrelation e-folding time scale has been used previously to estimate soil moisture memory. However, the theoretical basis for this metric (i.e., that the land water budget is reasonably approximated by a red noise process) does not apply at finer spatial and temporal resolutions relevant to modern satellite observations and models. In this study, two memory time scale metrics are introduced that are relevant to modern satellite observations and models: the “long-term memory” τL and the “short-term memory” τS. Short- and long-term surface soil moisture (SSM) memory time scales are spatially anticorrelated at global scales in both a model and satellite observations, suggesting hot spots of land–atmosphere coupling will be located in different regions, depending on the time scale of the feedback. Furthermore, the spatial anticorrelation between τS and τL demonstrates the importance of characterizing these memory time scales separately, rather than mixing them as in previous studies.

scholarly journals The Rothamsted long-term experiments: Are they still relevant?

1996 ◽  
Vol 76 (4) ◽  
pp. 559-571 ◽  
Author(s):  
P. R. Poulton
Keyword(s):  
Organic Matter ◽  
Global Change ◽  
Soil Fertility ◽  
Crop Yield ◽  
Atmospheric Pollution ◽  
Management Practice ◽  
Policy Makers ◽  
Land Management Practice ◽  
Long Term Experiments

Maintaining soil fertility and sustaining or increasing crop yield is of worldwide importance. Many factors impact upon the complex biological, chemical and physical processes which govern soil fertility. Changes in fertility caused by acidification, declining levels of organic matter, or P and K status may take many years to appear. These properties can in turn be affected by external influences such as atmospheric pollution, global change, or changes in land management practice. Long-term experiments provide the best practical means of studying changes in soil properties and processes and providing information for farmers, scientists and policy makers. This paper shows how the experiments run at Rothamsted in southeast England continue to provide data which are highly relevant to today's agriculture and wider environmental concerns. Examples are given of how crop yield is affected by soil organic matter, by pests and disease and by P nutrition. The effect of atmospheric pollution on soil acidity and the mobilization of heavy metals are also examined. The need for making better use of existing long-term experiments is stressed. Key words: Soil fertility, sustainability, long-term experiments, global change

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