Well this is kind of what I’m trying to help along as much as anything.
Phosphorus Liberator
- Thread starter Zan
- Start date
- Location
- Lincolnshire
Field ph 6.5 two years ago. Recent test was 7.5. Only difference......ab15 clover fallow. Can't really fathom it and will retest. Same across a range of fields - all swung from acid to alkaline.
Liming is so underrated.
If it was a new product with a fancy glossy leaflet and @Clive spread it using his Fendt,twin beacons flashing farmers would be falling over themselves to buy it.
Maybe lime needs sexing up a bit,perhaps @Kevtherev and @Cab-over Pete could get together to commission a calendar with the help of @Bald Rick as technical manager.
i've always said that pH and drainage are the 2 most important factors on any farm
amazes me the kit and snake oil people will spend money on in preference to getting those 2 very basic things right
we have found that cover crops seem to significantly reduce need for lime, p and k qty / frequency
more biologicaly active soils seem to maintain better balance themselves
- Location
- Lincolnshire
They don't call pH the master variable for nothing.
pH
Drains
Organic matter
And the effect on soil biology of pH is quite marked too.
pH
Drains
Organic matter
And the effect on soil biology of pH is quite marked too.
Bogweevil
Member
Sort of, humic/fulvic acid bigger, more complex molecules that affect soil texture. I reckon citric acid - cheapest/safest carboxylic acid. Often used to get liquid fertilisers to dissolve properly in hard water areas.
Bogweevil
Member
Ammonium sulphate - 100g neutralises 140g of lime, but realistically if you have a pH of >7 you will have free calcium carbonate present and you will never drop the pH significantly. Never mind, these downland and brash land farmers get by somehow.
If your soils have naturally high pH because of limestone then you'll be fighting a never ending battle to adjust pH downwards. Imagine the dilution of 10l spread over a ha (5litres/acre ish)?
First up, you don't have a problem with low soil P if you have soil indices of 2 and over....... but it sounds like you're having difficulty building the soil P index up though?
Cab-over Pete
Member
- Location
- Kenilworth, Warwickshire
Liming is so underrated.
If it was a new product with a fancy glossy leaflet and @Clive spread it using his Fendt,twin beacons flashing farmers would be falling over themselves to buy it.
Maybe lime needs sexing up a bit,perhaps @Kevtherev and @Cab-over Pete could get together to commission a calendar with the help of @Bald Rick as technical manager.
I’ve said countless times that if lime was sparkly like glitter and folks could see for miles around that you were using it there would be far more interest in it.
Maybe if you went around dressed sparkly like glitter you’d get a bit more noticed...
Not disagreeing but you can have peaty soil full of organic matter,air and water but acid as hell.
Its all about the optimum balance.
The peat formed in the first place through incomplete breakdown of the organic matter due to waterlogging. Waterlogging creates anaerobic conditions..... so if there was air then it's be a good soil, like the drained fens etc etc. Optimal pH for peat are 5.8.
Really?! Lots of lime used in the fens
The agronomist is partly right. These chicken/power station by products like P Grow/Cropkare/Kalphos/Fibrophos have a far bigger surface area from being fine vs a big fat TSP granule so are more readily available. It’s all right to say that it can be locked up but it needs to be put into context of what you’re comparing it to.
If you want a quick hit of P then a soluble product like slurry, MAP or DAP are best but over time IMO you want good indices built up anyway you can with what’s available at good value and have a healthy soil that enables the biology to access the reserves.
Bogweevil
Member
My understanding is this:
Phosphorus in soils occurs almost exclusively in the form of orthophosphate with total P concntrations usually in the range of 500-800 mg/kg dry soil. Quite a substantial amount of this P is associated with organic matter and in mineral soils the proportion of organic P lies between 20 and 80% of the total P.
From the viewpoint of plant nutrition soil P can be considered in terms of ' pools' of varying accessibility to plants. Phosphate in the soil solution is completely accessible but this makes up only a minute fraction of the total soil P. The bulk of soil P is virtually inaccessible. More than 90% of total P is present as insoluble and fixed forms including primary phosphate minerals, humus P, insoluble phosphate of Ca, Fe and AI and P fixed by hydrous oxides and silicate minerals . This fraction can be described as non labile.
A proportion of insoluble phosphate is more accessible than that of the bulk reserves . In this labile fraction solid phosphate is present in phosphate precipitations and is also held on soil surfaces . The labile phosphate is in rapid equilibrium with soil solution phosphate. Removal of phosphate from the soil solution by plant roots disturbs the equilibrium between the soil solution , P concentration and the labile pool at the solid soil phase which leads to a release of P into the soil solution.
These three fractions are shown schematically in Figure 9.1. As well as showing the accessibility of the phosphate pools to the plant it can also be seen that after addition of phosphate to the solution, substantial amounts of P can be fixed in the non labile fraction . The non labile fraction is also a source of very slow release of phosphate. This concept of pools of accessibility within the soil is of great importance in relation to understanding the use of P fertilizers in crop production.
Source: https://link.springer.com/chapter/10.1007/978-94-010-1009-2_9
So you slap on MAP, DAP, TSP etc and it is quickly added to virtually inaccessible soil P - this is not picked up by soil analysis and is only available very a long period. Bogger. But there you are; much, perhaps most of the P spend won't be used by crops in your lifetime. Makes you wonder if there is not a better way; band placement at seeding, seed dressing, boosting mycorhizzae ... or adding organic acids. Apparently not, at least yet.
Phosphorus in soils occurs almost exclusively in the form of orthophosphate with total P concntrations usually in the range of 500-800 mg/kg dry soil. Quite a substantial amount of this P is associated with organic matter and in mineral soils the proportion of organic P lies between 20 and 80% of the total P.
From the viewpoint of plant nutrition soil P can be considered in terms of ' pools' of varying accessibility to plants. Phosphate in the soil solution is completely accessible but this makes up only a minute fraction of the total soil P. The bulk of soil P is virtually inaccessible. More than 90% of total P is present as insoluble and fixed forms including primary phosphate minerals, humus P, insoluble phosphate of Ca, Fe and AI and P fixed by hydrous oxides and silicate minerals . This fraction can be described as non labile.
A proportion of insoluble phosphate is more accessible than that of the bulk reserves . In this labile fraction solid phosphate is present in phosphate precipitations and is also held on soil surfaces . The labile phosphate is in rapid equilibrium with soil solution phosphate. Removal of phosphate from the soil solution by plant roots disturbs the equilibrium between the soil solution , P concentration and the labile pool at the solid soil phase which leads to a release of P into the soil solution.
These three fractions are shown schematically in Figure 9.1. As well as showing the accessibility of the phosphate pools to the plant it can also be seen that after addition of phosphate to the solution, substantial amounts of P can be fixed in the non labile fraction . The non labile fraction is also a source of very slow release of phosphate. This concept of pools of accessibility within the soil is of great importance in relation to understanding the use of P fertilizers in crop production.
Source: https://link.springer.com/chapter/10.1007/978-94-010-1009-2_9
So you slap on MAP, DAP, TSP etc and it is quickly added to virtually inaccessible soil P - this is not picked up by soil analysis and is only available very a long period. Bogger. But there you are; much, perhaps most of the P spend won't be used by crops in your lifetime. Makes you wonder if there is not a better way; band placement at seeding, seed dressing, boosting mycorhizzae ... or adding organic acids. Apparently not, at least yet.
So not being anywhere near an expert if liming (sorry for banging on about lime) makes a greater quantity of p available by rectifying ph then this is the most simple and cost effective way of releasing it in greater quantities?