how does soil sample size affect drainage and water retention?
413795
the finer, more clay-like the soil the more the soil absorbs water and doesn't drain.  The larger the particle the easier to drain through...no retention.
317241
http://www.biologyreference.com/Ve-Z/Water-Movement-in-Plants.html\n\nThe Cohesion-Tension Theory\nThe major mechanism for long-distance water transport is described by the cohesion-tension theory, whereby the driving force of transport is transpiration, that is, the evaporation of water from the leaf surfaces. Water molecules cohere (stick together), and are pulled up the plant by the tension, or pulling force, exerted by evaporation at the leaf surface.\n\nWater will always move toward a site with lower water potential, which is a measure of the chemical free energy of water. By definition, pure water has a water potential of 0 MegaPascals (MPa). In contrast, at 20 percent relative humidity, the water potential of the atmosphere is -500 MPa. This difference signifies that water will tend to evaporate into the atmosphere. The water within plants also has a negative potential, indicating water will tend to evaporate into the air from the leaf. The leaves of crop plants often function at -1 MPa, and some desert plants can tolerate leaf water potentials as low as -10 MPa. The water in plants can exist at such low water potentials due to the cohesive forces of water molecules. The chemical structure of water molecules is such that they cohere very strongly. By the cohesion-tension theory, when sunlight strikes a leaf, the resultant evaporation first causes a drop in leaf water potential. This causes water to move from stem to leaf, lowering the water potential in the stem, which in turn causes water to move from root to stem, and soil to root. This serves to pull water up through the xylem tissue of the plant.\nFrom Root to Leaf\nPlants have root hairs and often mycorrhizal fungi at the root surface, both of which serve to filter the soil water as it enters the plant. Mycorrhizae are symbiotic associations between plant roots and fungi. The root cells and mycorrhizal fungi both actively uptake certain mineral nutrients. Mycorrhizae can be particularly important for the uptake of phosphate. The active uptake of minerals by living cells of the root and the subsequent transfer of minerals to the xylem can result in positive root pressures, with water potentials above 0 MPa. This occurs only under certain conditions, such as at night or during rainstorms, when water loss from the leaves is minimal. Such positive root pressures disappear with the onset of leaf transpiration.\n\nWater molecules move from the soil into living cells of the root, and eventually into the transport cells of the xylem, known as tracheids and vessels. These xylem cells are dead and hollow, allowing rapid water transport. They also have hardened cell walls to help them resist the tendency to collapse as water is sucked through them. Both tracheids and vessels \n\n \nA drop of guttation, water extruded by a plant's root pressure, on a blade of grass. have pits on the sides of their walls, which include porous areas for side-to-side transport. Unlike tracheids, a vessel is composed of many cells stacked end to end, with perforations between cells, allowing for more efficient transport.\n\nThe long-distance transport of the water molecule occurs first within the xylem cells of the root, then the xylem of the stem and branch, and then into the xylem of a leaf midrib and vein. Driven by transpiration, the water molecule is pulled from the nonliving tracheids and vessels of the xylem in the living cells of the leaf mesophyll (middle layer) and to the surface of mesophyll cell walls. The water molecule then evaporates into a leaf inter-cellular air space and finally out of a stomatal pore and into the atmosphere. Though photosynthetic action consumes some water, only a small fraction of the water that travels through the plant is used directly for the photo-synthetic reaction, which occurs in leaf mesophyll cells. Instead, most water is lost by transpiration through the stomates.\nThe Role of Stomates\nLeaves of land plants are covered with a waxy cuticle that pr
107613
maybe you hang out on the computer too much???thats my problem...maybe you should rotate your crops..or find the ph of the field..maybe your fields need nitrogen.how about drainage?..go to the us dept of agriculture websight and they may help
1018827
It will depend on the water pressure and the size of the orifice of the sprinkler head.
642291
http://natres.psu.ac.th/Link/SoilCongress/bdd/symp9/1375-t.pdf
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Yes, soil moisture.\n\nBut how about the degree of ionicity of the soil; wouldnt that depend on the kinds of minerals in the soil (which is likely to vary as well)...\n\nCordially,\nJohn\nhttp://www.GodSci.org
368508
I have not found any one source. This requirement entails research based upon need. Such as below soil mean temperatures that will vary to a certain depth which vary in accordance with density of the subsoil. In construction most General Contractors can advise on Frost levels and drainage which are your primary concern (perhaps). In building airports there are charts that provide "prevailing wind" information. Some of these also give ground or surface temperature readings. These are available through Government publications.
104654
Geography homework huh.\n\nBroadly.\n\n1) Improper removal of stubble or fallow cover leading to  erosion.\n\n2) Insufficient fallow time leading to decline in soil fertility.\n\n3) Over removal of tree cover leading to water table elevation and/or salinity.\n\n4) Over production of single crop types crops leading to nutrient depletion.\n\n5) Over-irrigation leading to turbidity and and slainity in irriagtion water sources.\n\n6) Failure to control tree growth within catchment leading to excess infiltration and loss of runoof. Irrigation water fails.\n\n7) Excess tillage of fragile soils leading to erosion.\n\n8) Tillage of soils in anticipation of  planting conditions that fail to transpire. Ground remains loose and without plant cover for extended periods and erodes.\n\n9) Overgrazing leading to desertification which encroaches on arable land.\n\nThat probably covers most of the practices that have caused land loss in the poast 6000 years.
424828
Soil and climate conditions.
181514
It's hard to say. Soil doesn't actually grow. It is produced from weathering of rocks that get transported and also degradation of biogenic material. Therefore, the growth (increase) of soil depends on how much rock debris and biogenic material is added to the soil in a certain place. The reverse can also happen. Soil erosion can cause soil to be reduced in a certain place. So, there's no straight forward answer to your question. However, if there is no change in the soil, then, due to the higher specific gravity of a coin compared to soil, it will gradually sink in the soil when subject to rain and other sources of water. But, how much it will sink depends on the type of soil and amount of water received by the ground.
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b.root hairs were destroyed.\nthis is because the water is first absorbed by the capillaries in the root hair and then transmitted to the pith.\nthe phloem has no role in absorption.\nhumidity will matter only in the long run as the roots absorb water already in the soil.
922712
there is a whole science that adresses exactly what you mention\nWATER HARVESTING\n,dig small dams every where to cath the rain water, and you can archieve that all of the rain water is absorbed by the land ,it will seep slowly into the ground to add to subteranean water suplies ,make sure that all the dams are interconnected by slow gradient ditches .just because you dont see water ,does not mean that it is not there .\nNormally a land repels water and with the rains it runs over ground into the rivers and awy.\nthink now that you want to make the land receptive or absorbent of all the water that falls on it.\n\nMULCH\ncut down the weeds before they produce seeds and leave them where they fall,they will cover the ground and put even more organic matter on top,you can use saw dust,leaves green or dry,and when you plant make a little space and plant in the mulch.this is the easiest quickest and by far most benificial way(for the quality of you soul)to prepare the land for planting\n\nto prevent weeds from coming all you have to do it turn out the lights,you can even use cardboard or black plastic(this is good for strawberries because they will rot if they touch humid ground,and the bugs can get to them).\n\nwhat you do is to cover the ground with mulch which is the same principal as compost but it includes the whole garden surface\nthe top part of the soil where the topsoil is being produced houses a world or microbiotic life.\n\nMulch is organic material green or dry that covers the ground,the thicker the better the composting process will turn it in to black topsoil\n\nthe humidity is preserved underneath and promotes the devellopment of worms(their exists no better compost than their excrements)and a variety of micro biotic life which together with the mulch produce more topsoil.\n\nthe mulch also keeps the ground temperature even and guards against the impact of the rain ,which would other wise brings salt to the surfave if on unprotected land\n\nMulch also prevents the soil from drying out because of the sun and, lay it open to wind erosian.\n\nand it turn out the lights for any weeds that want to come up\ndo not use chemicals because the water will wash them into the ground and if enough people did that, you would be guilty of helping to contaminate subteranean water suplies that other people could be pumping up to drink \n\nSUSTAINABLE FARMING\nthe best examples on this Earth of sustainable agriculture,\nare the chinampas of central Mexico ,the surviving ones(that have not been consumed by urban devellopment)have been going for more than 800 years ,that is sustainability.\nthe are built from the mud of the lakes and enriched with compost ,in the old days with the toilet contents of the outhouses that were on the bridges going into town,which the indians collected with a canoo.\n\nAnother example are the traced gardens of the Inca which have been going for more than a thousand years,there success is also because of the principle of using compost and their form which id a receptive concave absorb the rain waters and collect the dust from the wind (for hundreds of years and so increase in quality instead of the oposite.\nin the Ukraine are also examples of ancient agriculture due to no till farming and mulching(green organic matter that is added)\n\nin Mexico today are still examples from old Indian agricultural practises of diversity or companion planting.\nwhere by a series of 7 or 8 species of plants are put together or one folows the other.to create biodiversity ,and utilisation of space.\nCorn is planted for example ,wich is followed 4 weeks later by a bean that climbs it.\nand agavi and edible cactus is on the sides to protect these plants from foraging animals and add chemicals to the soil by their secretions.and others are in between to provide groundcover\n\nthere are many forms of sustainable farming in the past,and today those who follow the principles of permaculture,no till farming,organic or sustainable farmin
176815
The best water retention capacity is\n1) Clay\n2)potting soil\n3)sand\n4) dirt.
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I assume this is based on the principle of Osmosis. I would like a bit more data before answering further.
599976
There are any number of examples. \n\nFor example many plant species and even entire communities have distributions controlled by soil type to the degree that it is normal to refer to sandstone communities or basalt communities.
52661
after looking around at the usgs fl page for groundwater levels and recent precipitation records, i would guess that your water table has risen somewhat. from what i gather, this is normal fluctuation.  my answer is nothing more than a guess, because the data i looked at doesn't really support any other cause.  (all that just to say "I don't know.)
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SURFACE AREA INCREASES\n\nIT'S VICE VERSA