Why should we add soil particles from outside sources when there are many other promising alternatives available for improving soil physical properties...so extensively available in literature....

because soil texture is a relatively constant property (not easy to change) and an important property which also governs other properties such as soil structure .... so I may ask back:

which promising strategies do you see for soil physical improvement (so extensively available in literature) and which would you particularly devise for certain regions, climates etc. .... ?

we can keep my research question more general and ask for any "soil conditioner" (material added to a soil) in order to improve it's physical conditions? so how?

regards,

Niklas

Lets look at the role of microbial inoculation , cropping sequence , organic manuring , integrated nutrient management , conservation agriculture , and so on...These are possibilities which have been able improve soil aggregation , hydaulic conductivity or water transmission properties of soil , ...

partly agree with some common measures .... despite soil structure being a variable that is hard to define, isnt soil texture a main determinant of soil physical characteristics? e.g. could a sandy soil soil benefit from a addition of silt or clay particles (won from physical and/or chemical alteration of rock material)?

I'm afraid that mechanical approach to that issue isn't the right one. It's true that texture is one of the main factors determining soil physical properties but in reality soil structure is playing a crucial role in soil physical properties. Let say if solution to the problems of heavy soils would be only addition of certain quantity of sand particles or contrary adding clay particles to sandy soils this solutions would be implemented in great extent. If you have a bad soil structure addition of mineral particles will not change at least soil micro structure. You can obtain improvement of soil water and air characteristic with change of soil structure i.e. with change of organic matter content, addition of lime in acid soils or with change of cultivation practice….

thank you Matej for your answer. I was hoping for that kind of answer and it is in accordance with of what I think aout the topic.

If I got you right, ultimately, soil structure will determine pore size and distriution and therefore soil water and soil air characteristics. Less clear is the connection between soil texture and soil structure, though texture also determines structure (to a certain extent).

So, what is ultimately sought (can we agree with that?) is an improvement in soil structure. I think the problem lies in the exact definition of what a good soil structure is and how it is achieved (by certain organic matter bindinding particles together, formation by soil fauna, clay particles, wetting and drying, shrinking and swelling, etc.).

So then, the answer would be complex, depending on each particular soil and climate. Though complex, there could still be a potential for improvement of soil structure and in consequence yield. With respect to this, I also think that general recommendations such as adding organic matter (what kind, chemical and physical make up?) would NOT always be beneficial for soil structure.

the question I have:

- How would you judge the potential for soil structural / physical improvement (feasibility) and also the possible chance to improve crop yields?

thank you.

regards,

Niklas

Hello Niclas,

yes, you understood me right, the soil structure is the main factor determining soil water/air characteristic at least to the point of soil field capacity. Regarding the judgment of potential for soil structure improvement, I don’t think you have a simple tool to do that. As you have already mentioned addition of organic matter is always beneficial. However the answer to which extent you have to raise the organic matter content in the soil you will get only with soil physical measurements and plant response through yield and quality. However rising the organic matter in the soil is slow process …

All the best

Matej

For a long term benefit, I suggest green leaf manuring when there is assured water for irrigation. Done for three seasons, be rest assured, soil physical condition would improve significantly to profit the crop grown.

A different way to look at this problem is to consider what features are limiting production. The web site http://soilwater.com.au/bettersoils/module_map.htm goes into examining each part of the soil/crop/water process to identify any limits to production. This site also lists all the things which you need to test and what you may need to do. A recommended method of testing is to take an area large enough to measure yield properly - eg 3m x 100m. and apply a treatment to that - some treatments are expensive , but this way you can see what happens to productivity and profitability.

@ Cliff ... thank you for the link, I will look through it. I think your approach, measuring yield response to certain treatments is always useful in terms of practical consequences for productivity/production.

I am still looking for production increases due to innovative, new physical measures. It could be anything, e.g. micro/nanomaterials improving CEC (phyysics and chemistry "merge") ... however I am not an expert on that field (just graduated from university)

my broader motivation is to identify yield gaps (on a worldwide scale) and to close them (new innovative measures could facilitate it = closing yield gaps become economically).

'new innovative measures' depend on where you are and what crop/ soil/climate you are dealing with and the capital resources of the farmer. I repeat, the first step is to identify a crop or location where the yield is below optimum. Then you need to examine the agriculture system/soil/ climate to identify what is limiting the crop. When you identify the limitation, removing the limitation is often simple - SOMETIMES it requires an 'innovative measure' but usually not. Sometimes removing the limitation is impossible - like when the rainfall is inadequate.