At Kiwi Fertiliser we are specialists at balancing the soil, having undergone intensive training. If you are contemplating Lucerne as a crop, read on for extensive information.

Lucerne is not a crop that can be rushed into service. The first step is a soil test to establish what is required by way of fertiliser. We recommend PAL in Missouri, so we take samples and complete the paperwork for you.

Lucerne is a very high quality but hungry crop. With a benign climate becoming less reliable, Lucerne offers the opportunity to at least part drought-proof your property and profit. In addition, expensive bought in feed can be reduced or eliminated.

Many crops in NZ are not at all performing to their potential because they are underfed. These crops invariably suffer from weed, pest and disease problems, including premature leaf-drop, and eventually peter out long before they should. Often they are yellow-coloured in spring.

The solution is to balance the soil with quality fertiliser products. In most cases, some capital fertiliser is required, but it can be applied progressively as the budget allows over the first two seasons.

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The ryegrass over-sown Lucerne is 70cm tall. This stand has improved immensely since changing to a Kiwi Fertiliser soil fertility programme.

Shortcuts never work. If the crop requires certain fertilisers within a year, they must be applied. The paddocks need to be properly selected and well prepared. That could take a year or more depending on the circumstances. If the paddock is chosen in advance, certain materials such as lime, Dolomite and boron can be applied early, to the existing pasture.

The crop needs to be in the ground by the first week in April, or you should delay until spring. If spring sowing, try to get it in before October 1st, otherwise yield will be decreased for the first year. Spring is the preferred season for planting. Lower temperatures in autumn encourage root growth, but not vegetative growth. That can lead to weeds out-competing the Lucerne.

Up to 20-22 degrees soil temperature, more root growth takes place. Over 22 degrees, more top-growth takes place, so this sets the calendar for establishment. There is risk of dry summers, so it is important to be on time unless irrigation is an option.

The key to soil fertility is calcium and magnesium. If a soil has a deficit of calcium and magnesium, plants will not be able to get their full ration of either nutrient. If sulphur is below optimum, plants will not get the correct amount of calcium and magnesium either.

It is very common for us to see sulphur at the incorrect level. The deficits can be rectified by the application of calculated amounts of lime and/or Dolomite. Lime will release its nutrients over three years; dolomite over 18 months, so benefits will accrue well past application and need to be factored in correctly.

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The veteran grower of this Lucerne was taken by surprise by the prolific growth. The cows are on the last break. Bloat is not an issue.

A 20t/ha crop of Lucerne will remove 500kg of nitrogen. 70% of that will come from the air if the Ca:Mg is correct. That’s 350kg; about 100kg will come from the soil leaving 50kg to be added. Do you add N to your Lucerne? Most phosphorus levels we see on flat land are excessive. (E.g. 1100kg/ha when 560 is all that is needed.) For the few soils needing phosphorus, stay with alkaline phosphates.

We find the two most deficient elements are sulphur and potassium. Get sulphur levels to at least 50ppm. Excellent levels are 100-150ppm. The better the humus, the better it will retain anions. That opens the door for compost.

At Kiwi Fertiliser, we add 250kg/ha or more of high quality compost when we can; or a lesser amount of humates. Often potassium is half or less of requirement. Where animals graze pastures, adding potassium has its challenges. But if the crops are used for supplement, the opportunity to correct potassium must not be missed. In fact, it is essential.

Correct calcium and magnesium levels in the soil are vital for controlling potassium levels in the herbage. Potassium translates into quality, quantity and disease tolerance. It hastens recovery after harvest, and ensures long-life of a stand. Leaf-drop and spotting are eliminated. It also improves leaf to stem ratio, winter hardiness, and N-fixing.

But there is a catch. The higher the potassium content of Lucerne, the lower the calcium, magnesium and sodium content. The higher the chlorine content, the lower the nitrogen, sulphur, boron and phosphorus content. This means lower protein and lower quality. We prefer to use potassium sulphate, not potassium chloride.

Concerning trace elements, boron is essential and needs to be at least 1.75ppm. Copper at 2-15ppm, preferably 10 or more. Zinc must line up with phosphorus. High phosphorus, high zinc & vice versa. Iron must always read higher than manganese; not the other way around. Selenium confers insect tolerance, and cobalt and molybdenum are essential for nitrogen fixation.

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This crop was planted in early May 2013.

Lucerne observations and more

There are several things that caught my eye while scanning through a Beef and Lamb Lucerne blog. Chemicals, insects, weeds, and fertiliser are among them.

The Americans use Alfalfa to mop up nutrient excesses. We seem to use Lucerne to create deficiencies. The American excesses are a result of feed lot manure from 50,000 or whatever number of cattle being spread on relatively small areas of land. They then plant Alfalfa and cut that for forage for the cattle for a few years, then perhaps lease the area out to a vegetable grower for a while before the cycle starts again. They are not legally allowed to use the manured areas for at least two years to produce food for human consumption because of Salmonella concerns.

Lucerne is a gross-feeder. It is a very hungry crop. If you want it to out-last and out-compete weeds, then feed it. If you want to produce 20t/haDM and more, then that crop will remove approx. 500kg N, 440 K, 275 Ca, 56 P, 56 Mg, 56 S, and 1.2 Mn, 1 Cu 0.8 B 0.4, Fe 0.4, Zn 0.3, and Mo 0.02. These figures may vary, but what matters is, the crop will take all you throw at it, and in 90% of cases, more.

Let’s work through the list.

Nitrogen, 70% from the air is 350 kg; then 100 kg from the soil is 450 kg, leaving 50 Kg to be applied from the bag. That 70% from the air is not by right either. You’ve got to earn that right. That is achieved by ensuring you have:

(1) adequate calcium and magnesium in the correct amounts. This requirement is calculated for each soil.

(2) Available phosphate, at least 560kg/ha.

(3) Available iron, at least 200ppm, but be aware, iron may be found at depths beyond the soil probe.

(4) Cobalt at about 1ppm and

(5) Mo at about 1ppm.

crops lucerne 04

This crop is not on a Kiwi Fertiliser programme, but is run by a farm consultant. Among other things, it is probably subject to too much calcium and not enough magnesium. Note the weeds. On our crops, other than at establishment, no weed sprays are necessary.

Potassium is perhaps the nutrient we have found to be the most deficient; about 50% in a lot of cases. Not only that, but most people use potassium chloride because it is the cheapest form of potassium. Bollocks! Use potassium sulphate instead. For a start, you won’t get those aphids we keep reading about. I've seen them on neighbouring crops too, but they are only a temporary on our crops, at the beginning of when a grower converts to our programme. You won’t have to spray toxic chemicals. You’ll grow a better crop. Besides that, there are many reasons to change and they all point to greater profit in your pocket.

  • More Energy. Potassium Sulphate costs more per unit, but delivers better value. Money spent on potassium sulphate will purchase less fertiliser by weight than will one dollar on potassium chloride; but the dollars spent on sulphate will buy significantly more crop growth energy. 47% of potassium chloride is chloride and of little use for crop growth. The more chloride plants have, the less anions they will have, including sulphte and nitrate. In contrast almost 100% of potassium sulphate is useable by the plant.
  • Lower Salt Index. Potassium sulphate has a salt index of 46. Potassium chloride is 116. The higher the index, the greater the chance of damaging germinating seeds, seedlings and soil biology.
  • Better Uptake of Potassium. Uptake of potassium requires it to be in the phosphate of potassium form. When there is an excess of chlorides the bonding of potassium with phosphate is blocked. The end result is less potassium uptake into the plant in the preferred form. The sulphate form does not overwhelm the soil solution with chloride ions and consequently more potassium is taken up by the plant.
  • Microbial Stimulation vs. Microbial Suppression. Sulphates have a stimulating effect on the microbial system in the soil whereas chlorides at high levels are very hard on soil biology and are seldom recommended by creditable sources. A small amount of chloride is actually beneficial for soil microbes. This modest requirement is easily met by the 1-2% in potassium sulphate.
  • High rates of chlorides can destroy soil carbons. Humus destruction leads to greater nitrogen leaching as soil nitrogen levels are dependent on humus levels. The better the humus percent, the more anions (particularly nitrate, sulphur and boron), are held in the soil, and the better the moisture retention. Potassium chloride is the product above any others that makes your soil as hard as concrete in summer.
  • Plants and soils need sulphur. Most NZ soils are sulphur deficient. In order for plants to make oils and sulphur bearing amino acids such as cysteine and methionine the plants need an adequate supply of sulphur in the sulphate form. This is exactly what potassium sulphate supplies.
  • Better palatability. Pastures, crops, vegetables and fruit taste poorly when the potassium comes from potassium chloride (that’s right, even stock prefer fodder grown with potassium sulphate). This happens because chlorides are also taken up by the plants. Fruit and vegetables grown with calcium chloride taste bitter; this is the main reason why children reject vegetables.
  • Less is more. The application of 100kg of sulphate will usually give a greater plant response than 200kg of chloride. This relates to a soil where the cations are balanced and soil potassium is adequate.
  • Potassium translates into quality and quantity. The life of your stand depends on it. Potassium is vital for quality and yield. It hastens recovery after harvest, and ensures long-life of a stand. Leaf-drop and spotting are eliminated. It also improves leaf to stem ratio, winter hardiness, and nitrogen-fixing.
  • Calcium. How many of you add calcium to change pH? How about adding calcium because the soil and the plants need calcium? Calcium, along with boron carries other nutrients into the plant. Leaf test prior, then apply Ccalcium alone, test again and see the difference in levels of all nutrients. Each soil has its own sweet spot as far as calcium (and magnesium) is concerned. That can only be established after soil testing and calculating it.
  • Phosphorus is required between 336 and 560kg/ha in the soil, (sometimes higher) depending on how light or heavy it is, but mostly around the 560 level. I have seen many soil tests where it is about 1,000, and still the farmer is too scared not to apply more. What a waste of money, quality and potential.
  • Magnesium. How many of you apply lime without magnesium? Each time you do that, the magnesium percent of the base saturation is driven down on a 1 to 1 basis, provided it is high enough in the first place, which it rarely is. Many soils get over-limed too, making matters worse. Lack of magnesium (or too much calcium) can cause yellowing in Lucerne foliage. However, deficient nitrogen, sulphur, manganese, and iron can also have the same yellowing effect, making a correct diagnosis difficult. As for calcium, the correct level of magnesium can only be established from a soil test.
  • Sulphur increases the girth of plants. It is required with nitrogen to form amino acids which in turn form protein. Too often it is left out, or too little is added to the fertiliser. It leaches because we are collectively converting soil carbon into atmospheric carbon. The higher the organic matter, the more sulphur you can attach to humus in the soil. Sulphur also influences flavour (palatability). It would be alongside potassium as the most deficient nutrient found.
  • Manganese needs to be 50-250 ppm in the soil. It’s involved with seed formation & can improve germination and survival of seeds for those growing seed crops.
  • Copper is needed from 2 ppm to 15 ppm. The higher side is better. It improves plant and stock health benefits and confers elasticity in plants, so they will stand up better, reducing lodging. Fruit growers do not appreciate branches breaking when loaded with fruit. Correct copper, potassium and manganese can prevent that from happening.
  • Boron is hugely important, partnering calcium and silicon. Without boron, the plant cannot transfer sugars from leaves to the roots. Boron is required at at least 1.75ppm in the soil. Boron toxicity is not a consideration when the calcium level is correct.
  • Iron needs to be at least 200ppm, but always at least 5ppm ahead of manganese. There are plenty of soils out there the other way around. You really don’t want to be in that category. The manganese will oxidize the iron in the leaf in that situation. Iron can be found beneath the depth of a soil test probe, so do not apply iron before ascertaining that the situation requires it.
  • Zinc partners phosphorus. If phosphorus is high, zinc needs to be 19.5 ppm in the soil. If phosphorus is very low, zinc at 6 ppm is adequate. There are many cases of high phosphorus but low zinc all over the country. In those cases, water efficiency will suffer. If zinc is high & phosphorus is low, the phosphorus will be blocked. When it is the other way around, zinc uptake by plants will be blocked. Either way, water efficiency of the plant suffers.
  • Molybdenum needs to be at 1ppm in the soil. I have seen dozens of soil tests where it is around 6-8 ppm. If that is the case, get the copper up pronto. I have only recommended molybdenum to be applied to one crop I have tested. That was citrus and the grower pointed out the visible symptoms that were later confirmed by the PAL soil test. The molybdenum level was 0.95ppm, but those deficiency symptoms were quite visible.

Insect pests and other problems

It seems this phenomenon is very common. That may have you thinking it’s normal. It’s not normal at all. If you get aphids, caterpillars or whatever, change your soil fertility advisor. Either he/she is not recommending the right fertilisers, or you are not spending enough on the right products and too much on the wrong products.

Insects are not the result of a deficiency of toxic sprays. Insect problems are a result of poor plant nutrition. Poor plant nutrition stems from nutrient imbalances in the soil. Those imbalances transfer to stock as well. Get the soil nutrition right and never spray poisons again.

I've mentioned potassium chloride above. Not enough potassium has a similar effect; so do chemical sprays. Protein synthesis needs to take place, not proteolysis which is the opposite and occurs when the plants are not nourished properly.

“It was discovered that the degree of virus disease increased with the dosage of atrazine. A dose of 20 ppm applied to the soil increased symptoms by up to 100%. That was because the toxin altered the biochemical composition of foliar tissues, particularly phosphorus, potassium, calcium, iron, copper, boron, aluminium and zinc. Plus nitrogen levels were elevated in both corn and sorghum. Similarly, simazine increased nitrogen in wheat by 30%, and raised certain amino acids, including asparagine which is preferred by diseases; i.e. leafhoppers proliferated on maize. 2,4-D caused proliferation of aphids, caterpillars and fungi on maize. Other researchers came up with identical conclusions with 2,4-D use on oats and barley. Two prominent researchers concluded: “Since 1945, numerous reports tell of increased losses through insect and pathogen attack, despite ever greater efforts at pest control. While it is difficult to calculate to what extent these increases are due to the biochemical and ecological impacts of herbicide use, herbicides have been blamed in numerous cases for causing problems of parasitism in treated plants."

Nguyen et al. (1972) studied Alfalfa and stressed; "a good balance" of NPK leads to:

  • A decrease in the amino acid content of the tissues.
  • An acceleration of their incorporation into proteins.
  • An increase in yields.

Fenton (1959) found that treating Lucerne with parathion, toxaphene and dementon, increased populations of aphids.

The lessons to be taken from the above is to practice balanced nutrition; an activity easier said than done if you don’t know the rules.


If you have weeds, then the conditions suit them. Change the conditions to suit the crop as outlined above. Sure you may have to spray at the beginning, but once your crop is away, and you feed it properly, those weeds will not keep up. In two or three years, (or less) they’ll be gone.

If you do spray, add 1 litre/ha of Fulvic acid to the chemical. It is a carbon source and has the ability to reduce chemical damage to the soil and the plant, while enhancing the target kill without any other additives. The chemical rate can also be reduced. It’s a very cheap product.

crops lucerne 05

Spraying without Fulvic acid can damage the soil

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That damage is very much reduced with Fulvic acid

Hollow stems

Usually, Lucerne stems are hollow. Not only is a hollow-stem crop lighter, but it also lacks quality. The material that packs the stem centres is pectin. Pectin is made up of polysaccharides that contribute to quality and animal nutrition. Most farmers are growing hollow-stemmed Lucerne. Just cut a stem about 150 mm from the crown and check. If the stems are hollow, find out to what extent. It may start 50 mm above the crow, but become solid again 100 mm or 200 mm further up the stem. Our mission is to fill the stems with those goodies described above.

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Virtually all plants in this crop have 25-30 stems per crown.

Want real fertility results on your farm? Contact us today and request a soil audit.

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