Users positive about additive An increasing number of cattle farmers use AgriMestMix and Compost-O as additives in manure with the aim of improving the effect of the slurry and/or improving the composting of solid manure. Users are positive but ‘you have to believe in it’.

Although the heavens do not look very reliable, a large combine harvester rages across the North Frisian clay soil. The seventy-hectare pasture of Feike Tamsma in Jannum is being mown for the third time this year. “We’ll take the risk. The weather’s a bit uncertain, but the grass is fully grown and must be mown.” Tamsma has had his entire area mown for eight years. This is usually done four or five times a year. His approximately 175 dairy cows stay inside  all year round. “The system suits me very well, although it resulted in less dense turf.”


Tamsma met Sipke Scheepsma of Micro Nutrions in Surhuizum more or less accidentally. He advised him to use the bacterial mixture AgriMestMix ”I’m not really the kind of person at all for these products, but I started using it anyway,” says Tamsma. “And I wouldn’t do without it now. Just look, the turf is nice and solid now: I have at least as much silage as before, spreading the equivalent of about 25kg less pure nitrogen.” The Frisian businessman tells us how he mixes a number of litres AgriMestMix with water every week, which he then pours over the grids. “Overall, it only takes me twenty minutes each time.”According to him the product has other side effects. “The smell of ammonia in the stalls is a lot less; the product is more homogenous and more liquid so that the farm hand doesn’t need water now when drag hosing, and he gets it done more quickly than before too.”


Mixing is a different matter. “Silo mixing is no longer needed. Stall mixing is very easy too, but the cake on the manure is sometimes so thin that it is difficult for the mixer to handle this cake. That’s when mixing takes a bit more time.” Tamsma purchases the AgriMestMix mixture for a period of about 24 weeks. He pays €1250 for it, including VAT.“I buy less fertiliser and my fields produce similar yields and quality. So I think it’s worth it. But I can’t prove it. It’s a matter of believing that the product works, I think.”

(Photo) Heinie Alting with his goats, which can range onto the clover pasture.


That is exactly what Heinie Alting from Sellingen thinks about it.

He keeps about 700 dairy goats and 250 young animals under an organic system. He has a few hundred cubic metres of liquid manure supplied every year for his 28 hectares of clover pasture, which he treats with AgriMestMix. The solid manure in the deep stall is treated with Compost-O, a liquid additive for solid manure.“After using these products, I can just see what it does to the manure. And the most important proof is that my wife can no longer smell whether I’ve been in the stalls or not. It used to be quite different.”The Groningen goat farmer believes manure is the key basis for proper pasture management. “The first cut is the most important. The yield and quality can be slightly affected by the manure. After that, it’s up to the clover.”According to Alting, the utilisation of manure has improved after he used AgriMestMix and Compost-O. “I’ve got no statistics to prove it, but grass yields increase every year and the smell of the manure has improved as well. Normally, evaporation is a big problem, but these products bind ammonia better. At least, I feel good about it.”He also believes that the manure processing has improved too. “Solid goat manure is like concrete. That changed after using Compost-O, which makes me and the farm hand happier. The solid manure is loose now and can be spread on the land more easily, more quickly and better.”Alting uses about one litre  of AgriMestMix on twenty cubic metres of liquid manure supplied. geitenhouder_bij_vaste_mestThe Compost-O is sprayed on the manure in the stall pit once every three weeks. He uses a separate storage tank to spray the liquid from the feed troughs into the stable.  “It’s not really possible to use high-pressure jets for this, because the goats will knock me down. It’s quite a physical effort too. Doing it this way is rather easy.”The goat farmer tries out different types of pit every year.“Goats have a need for structure, but a little energy from a pit that feeds them faster is needed too, because they have to produce enough litres of milk, of course.”He also provides fodder to the various pits at the same time in order to offer the animals a balanced diet.Besides the manure, additives are also used for the grass silage pits.“To me, these additives are an investment in the total product. You can’t control the weather, but this does let you influence things slightly. And if you never try anything, you won’t get further either.”


(Photo) Alting shows how the stored solid manure composts and becomes loose at the end of the storage period.



No understanding between practice and science

The bacterial additive mixtures AgriMestMix and Compost-O are products made by Rinagro, owned by Rinze Joustra from Piaam. He bought the rights of the AgriMestMix product in 1994. According to him, people misused the product a lot during the first ten years, which was why it acquired a bad image.“AgriMestMix was introduced to the market as part of Effective Microorganisms (EM),” says Joustra. “A study had shown that EM had no added value, and AgriMestMix was included in the study too. So wrong conclusions were drawn about the product’s effectiveness.”Joustra reintroduced the product on the market in 2005. He says that he is still misunderstood by scientists. “They don’t understand what the product does. Our studies clearly show that there are advantages. Dairy cattle farmers get reduced urea levels in their milk and increased protein levels.”According to Joustra, nitrogen present in the manure as ammonia is retained when it is treated with AgriMestMix. “There’s less evaporation and emissions are therefore reduced The increased levels of nitrate in untreated slurry and fertiliser also block the uptake of phosphates. AgriMestMix makes sure that the phosphate can do its job. This improves rooting.” One of the sceptical researchers is Fridtjof de Buisonje of the Animal Sciences Group (ASG) of Wageningen University. “I’ve seen a lot of mysterious bacterial mixtures come and go over the years. Our experience is that emissions can only be reduced by adding toxic substances or certain acids. I therefore invite Joustra to have his products investigated by us independently.” “So far, our investigations have been independent,” is Joustra’s response. “But maybe I should let ASG do it this time. “But the number of users is doubling every year, even without these studies. After all, lots of cattle farmers see the results at their neighbours’ farms.”