Off course , i am bit too late to respond to this question , but  better  late than  never . We in perennial crops recommend to undertake analyis for P,K,Mg  at an every alternate years.  Putting too many slag years, probably will put the  potential impact of  fertilization in a bit of jeopardy. We very frequently use leaf nalysis in conjunction with soil analysis for addressing these nutrients with regard to their budgeting.

In Austria it is recommended to analyse the soil from arable land for fertilized nutrients about al 5 years. Sogar beets fields are sampled all years because to avoid loosing high yields and earnings. The link brings to to our regulations. Bye Stefan

https://www.google.at/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCMQFjAA&url=http%3A%2F%2Fde.slideshare.net%2FJohannHumer%2Frichtlinien-fr-die-sachgerechte-dngung-rl-sgd6&ei=4KZ6VK3NMIyvPMSVgPAF&usg=AFQjCNFWhKe4rWGBF1RJBeyDikoaKSqfoQ&sig2=BeUK640UPUARcN2A5kaokA

Hi Johann,

thank you for your answer. It is the same in Germany the recommendation is every 5 years but the most farmers collect soil samples every 3 to 4 years.

Best regards from Osnabrück

It depends on the purpose of sampling. Are the soil samples collected to provide an inventory of nutrient contents of the soil? I would suggest sampling prior to cultivation and post-harvest and once each year.

Dear Stefan,

For most arable soils in Ontario (Canada), soil testing is recommended once every three years.

More frequent sampling is recommended for some coarse-textured soils where crops that remove large quantities of potassium are grown (such as alfalfa, silage maize or processing tomatoes).

In the case of N fertilizer recommendation for maize grown for grain production, spring soil nitrate test (soil samples taken close to planting, usually late April or early May) is highly recommended for optimizing the rate of N, due to high N demand of this crop as well as the high cost of inorganic N fertilizer.

Susantha.

Hi, Yes it depends on the purpose of the sampling.  If it is for general management of a farm's soil fertility, then every 3-4 years is good.  Farms can then sample a proportion of the farm each year to spread any cost and/or labour.  The value comes from long-term monitoring to observe trends.  There has to be an adequate period after fertilizer application and soil sampling (3-6 months).  I have assumed this is for nutrients other than mineral N which of course is much more dynamic during and between seasons.

Dear  Jenkins,

Dear Susantha,

Dear Mark Anthony,

thank a lot for your answers! :)

The more valuable the crop and the large the nutrient removal, the more frequently you should sample. Also it depends on how you sample. For example if you do detailed precision sampling, a longer period is justified. of you do composite sampling, the cost is minimal so why not do it more often. For me, if your removing a lot of crop, and its a high value crops, i would sample every 1-2 years.

Hi Michael,

thank you for sharing your experiences with me!

Hi Stefan, like other people already said, it depends on the purpose of the sampling. For dynamic nutrients as N-NO3 it is recommended to sample every year and near the date of seeding, but for other nutrients as P you can take samples every three years 

Hi Alejando,

thank for your answer. Ja, for N-NO3 it is useful to do the sampling every year. Actually, my questions concerns the soil basic nutrients.

Soil nutrient removal will vary due to plant species, plant size, soil type, moisture and stocking rate (animal grazing). After crop removal and before a new crop of value is to be sown, sampling should be considered to produce a' nutrient audit'.  Consideration for differing sample methods, for example detailed precision sampling, a longer period is justified whereas composite sampling could be consistently regular. When harvesting large high value crops, sample every 1-2 years.

Hello Helen,

thank for your answer. That is very interesting, a few colleague also recommend at high value corps a period of every 1-2 years. 

SO, what is a HIGH VALUE CROP ???!!!

Best regards from Germany, Stefan 

High value crop refers to economic value, these crops have the capacity of a high return if nutrient audits are accurate along with moisture. Some broad-acre crops on arid land have specific sowing times, and growth periods (reference: Australia).  In the case of wheat for example 1000 ha paddock, seed and fertiliser costs can range from AUD$100,000 +, so estimating fertiliser requirements is essential (NPKS).  On a smaller scale of intense rotational cropping, crops of high value are for milking cows for quality milk production, crops preferred are high protein crops, once again nutrient audits for correct fertiliser input are essential.

Hi Helen,

Can you mention a specific example of a high value crop?

In Germany a high value crop is for example sugar-beets or vegetables. I would define it as a culture, which brings an above average monetary income in comparison to the agricultural crops like wheat, barley, maize, etc.

How would you define it in Australia?

Greetings from Osnabrück, Stefan

Off course , i am bit too late to respond to this question , but  better  late than  never . We in perennial crops recommend to undertake analyis for P,K,Mg  at an every alternate years.  Putting too many slag years, probably will put the  potential impact of  fertilization in a bit of jeopardy. We very frequently use leaf nalysis in conjunction with soil analysis for addressing these nutrients with regard to their budgeting.

Hello Anoop,

thank you for your answer !

Greetings from Osnabrück, Stefan

Let me propose another quarry in the context of ongoing discussion , so interesting dear friends.. What shall be the time of soil sampling in perennial trees ..?  Shall it coincide with the time of leaf sampling, regardless of acid or basic nutrients ...?

Let me put another quarry with a hope , someone will respond..

Can we afford to adopt different sampling times for appraisal on  concentration of different nutrients in any crop..?