400kg/ha of urea is a high rate. Much higher than probably all the readers would use on their pastures. But, how many extra lambs at today's prices would you need to pay for it? The answer is two. Our potential is ~50 lambs/ha.
I pose that question to many visitors that come to our farm who shake their heads at our pastures, in a good way. Fertiliser costs need to be put into perspective.
I will backtrack for a minute. One of my biggest problems with consultants who create budgets for their clients where the budget was showing a loss, is that they would decrease costs like lime and fertiliser, but not change the crop yields or livestock carrying capacity.
If you say yes to something, you are saying no to something else. If you cut back on fertiliser inputs, it is very likely that you will cut back on your potential crop yields, or in our case, livestock profitability. In the farm that I Chair on Kangaroo Island, cutting costs did not get them out of trouble. Creating wealth got them out of trouble.
If you have the rainfall, your fertiliser inputs should increase to create more wealth. It would be unwise to throw high rates of fertiliser where your rainfall is only 150mm/year, of course. But we have the rainfall. Usually. You can't run a marathon on toast and vegemite. In the same way, we can't grow the pasture that is possible, based on rainfall, unless we feed it with everything it needs to run the race.
One of the reasons of wanting to run this farm for investors is that there is so much profit to be made running a farm close to its potential in the high rainfall areas of southern Australia. One of the reasons why I wanted to be sole Director for the first few years is because I knew I would be under enormous pressure to farm like everyone else unless I had the decision making authority. After a few years of people seeing what is possible, then I would step down and allow much better people to take over the company and help it grow to where I have dreamed of it going. ie 1 million lambs/year as an example of one of the goals. When that day comes, I will still be charge of the pastures and training the staff.
The pastures in each hectare are where wealth is created. It is not created by decisions made over the horizon. So my aim is to have managers trained to know how to maximise pasture production efficiently and have people who are superb with livestock, while much better business people than me run the company for all the other decisions that need making day to day.
Liebig's model of how plant nutrition works is correct. If you still think optimum plant nutrition is based on cation ratios, we can have the argument another day, but that theory doesn't work. It's been proved over and over it does not work. Liebig's model is how nature works in regards to plant nutrition.
When teaching plant nutrition (Learning Plant Language), I would illustrate the process is like a ladder. Don't throw everything at the plants at once. Just start with what is known to be wrong or lacking. Often, fixing that problem enables the plants to explore the soil better and obtain nutrients better so that you do not need to add as much of other nutrients.
But as you push the growth upwards, the plants will start to show you what the next limiting factor is. So fix the obvious problem and raise the plant production further until the plants start indicating what the next nutrient is that is not abundant enough. It is like climbing a ladder. Just climb one rung at a time.
So with this first farm of Caluka Farms, the number one problem was soil acidity. So I fixed that with gusto because I was in a hurry to show investors what is possible. Life is too short to take things slowly. The next rung on the ladder was trace elements. Zinc (Zn), Copper (Cu), Molybdenum (Mo), Cobalt (Co) and Selenium (Se). We also have iron (Fe) deficiency now because I have pushed the growth potential up, and two small areas of manganese (Mn) deficiency.
Then it was to increase the phosphate (P) and potassium (K) while applying moderate rates of sulphur (S) and nitrogen (N). We now don't need to add any more lime for many years, and no more potassium is needed for at least a few years - healthy kikuyu brings up potassium from depth to deposit it on the surface as leaves. I am now able to apply maintenance levels of some nutrients while trialling higher inputs of various nutrients. By pushing the plants to grow more, they show me what the next limiting factor is. This is a crucial strategy in knowing what the pastures need to reach maximum production.
However, there is no point fertilising to the maximum unless you have the livestock to harvest it. Now that all the big limitations are fixed, or at least attended to (lime takes years to do its thing), I am now only going to be fertilising as much as is needed until we reach the maximum stocking rates. But, I am always curious to know what more can be done. Everytime I spread fertilisers, I am applying a double or quadruple rate in small areas to see what is waiting to grow, and I inspect those areas to see what nutrient deficiency might now be showing.
Applying more is not always better, but applying more of what is needed is the aim. Do you know if you have applied enough?
So back to my opening comment. 400kg/ha of urea sounds like a lot, but if you saw where I applied those strips, you will see it created many extra tonnes of pasture for the sheep. As the lime keeps working, the pastures should keep getting better and better. It is a work in progress and we have a long way to go, but I will try to get there as quickly as I can.