ALGERIE: 2 RECOLTES DE FOURRAGE PAR AN. C'EST POSSIBLE.

 COMME EN AUSTRALIE, FAIRE DEUX RECOLTES PAR AN?
Djamel Belaid 2/05/2016

Nous proposons un article sur une pratique en Australie. En Algérie, les potentialités du sol ne sont pas exploitées à fond. La preuve: la poursuite de la jachère. Mais même dans le cas d'exploitation avec zéro jachère, il reste du potentiel.
Comment exploiter ce potentiel? En faisant deux récoltes par an sans irriguer.Nous avions déjà aborder ce thème dans un précédent article. Un jeune australien explique comment faire. Nous prenons l'exemple de ce pays car du point de vue climatique, certaines régions ressemblent à celles d'Algérie.

- ce jeune fermier utilise le semis-direct, condition indispensable à un semis rapide,

- après la récolte d'une céréale ou de colza, il sème immédiatement du sorgho,

- le semis-direct sur blé permet d'emmagasiner plus d'eau et celle-ci reste en partie disponible pour le fourrage d'été (cela sur des sols profonds à bonne RFU),

- le semis de sorgho est réalisé tout de suite après un orage d'été,

- il s'agit d'un semis d'opportunité (une quantité de semence est toujours prête), le semis est réalisé s'il y a un orage.

Nous pensons que cela est possible en Algérie. Il faut choisir de bonnes parcelles, posséder un semoir pour semis-direct et tout faire pour maintenir l'humidité du sol: politique régulière d'apport de fumier, laisser si possible les chaumes (ou mieux la paille au sol en la broyant).

En Algérie, en septembre ou en juin, des opportunités d'installation de cultures sont possibles:

-septembre: colza fourrager pour pâturage,

-mai-juin, installation de sorgho. Evidemment dans ce cas, il faut libérer le sol le plus vite possible. L'idéal est d'installer par semis-direct un sorgho derrière un foin ou un ensilage de vesce-avoine récolté tôt.

nb: l'article est en anglais. Nous nous proposons de la traduire en français puis en arabe .

Photo: On distingue la moissonneuse-batteuse, l'opération de confection des bottes de paille et tout de suite derrière le semis de maïs (Ex URSS).

AUSTRALIE: MIXED FARMS TAKING ADVANTAGE OF ZERO TILL

SARAH JOHNSON 254-256 SANTFA The Cutting Edge WINTER 2012

Photo: Using a disc seeder to sow summer forage crops can have many benefi ts for farmers with livestock, says disc seeding contractor Nathan Craig.

Disc seeders give farmers the flexibility to move between crops and pastures with very little disturbance, according to Nathan Craig. “I can see there are advantages to having livestock and cropping together. The disc seeder gives you a lot more options because it doesn’t disrupt the soil and you can over-sow to boost production,” said Nathan, a Victorian farmer and seeding contractor.

Since the Craig family sold their 1,465 ha farm, near Apsley, across the border from Naracoorte, in 2009, Nathan has developed a contracting business that sows up to 5,000 ha each year. Many of his clients successfully combine livestock and cropping.

 If you get rain during harvest you can sow sorghum

Nathan uses a disc seeder that provides good seed placement and germination in ‘crab-hole’ country, improves the ability of young crops to access to soil moistureand opens the way for planting summer crops to provide extra feed for stock.

The Craigs were experimenting with summer crops for several years before they sold their property and bought a disc seeder the year before they sold. “Even though it was dry during the 2000s we were starting to double crop and grew some really good summer crops,” said Nathan.

“With a disc seeder you can just go straight in behind the header because you don’t have to worry about handling the stubble. You can bowl straight through. “If you get rain during harvest you can sow sorghum into harvested paddocks while you’re waiting for the remaining crops to dry enough to harvest. Ten weeks later, in March or April, you’ve got green feed for your sheep, right when you need it.”

This was exactly what he did on a property he was managing in 2010, when 73 mm of rain fell while Nathan was harvesting canola. “The header was still in the paddock and we had a few days ahead of us waiting for the country to dry out. We sowed the harvested canola paddocks to sorghum.

“We used sorghum because the root systems go up to a metre deep and you can sow it up to 50 mm deep, which improves the chance of achieving a reliable germination.

“By the time we finished harvesting that lock of land we had sorghum out of the ground. It wasn’t a fantastic-looking crop because that was the only rainfall we had that summer, but we still had sorghum 60 cm high to put the lambs on in autumn.

“Other farmers didn’t get a summer crop because they waited four or five days after the rain and the soil had dried off too much.

“In an area where the canola was washed out in winter the sorghum was 2.5 m tall because of the extra soil moisture, which showed it would be possible to grow some pretty amazing summer forage crops if we were prepared to treat them as the main crop rather than an opportunity crop.

“From what I’ve

seen, if you grow a sorghum crop then

go into wheat thenext year you’ll get

three quarters of atonne to the hectare

higher yield,”

This made us think more about how to use this in rotation and to feed livestock. We’ve never had this response in summer grain crops.”For summer forage opportunity crops Nathan advocates a speedy transition from header to seeder following a harvest rain to make use of the available moisture.

“I would either have half a tonne of seed on hand, especially if I saw a rain coming, or I’d make sure the supplier had a bit of sorghum seed with my name on it,” he said. “I’d have everything set up and would be out sowing while the sappy moisture was still there.

No till,  more moisture deeper into the soil.

“If our sandy loam got 25 mm of rain it would wet the soil to 30 cm but that moisture evaporates unless we grow something with it. It is critical to know how your soils wet up, as every paddock is different. No-till paddocks are definitely better for double cropping as they let more moisture deeper into the soil.”

He found planting sorghum as a summer crop also conditioned the soil, leading to

increased yields from wheat crops the following season.

“From what I’ve seen, if you grow a sorghum crop then go into wheat the next year you’ll get three quarters of a tonne to the hectare higher yield,” he said. “Even though the summer crop takes moisture out, there’s a synergistic effect that helps grow a better crop.

“Over summer the sorghum roots penetrate about a metre through the heavy clay. The paddock where I sowed the sorghum in 2010 had a duplex soil; 30 cm of lighter sand on top and 30 cm of heavy clay below that. “Water doesn’t get through the clay very quickly, so we had a lot of waterlogging in the top 30 cm. The sorghum used that moisture to germinate then pushed its roots through the clay layer to access moisture from the subsoil. The roots of the following wheat crop followed the path of the sorghum and lived on the nutrients and moisture that they left behind.

“This was before we had the disc seeder and the results blew me away. I thought ‘we’ve got to do this properly with a disc seeder’. The disc seeder allows you to retain more moisture for the summer crops because you can seed into the stubble with almost no soil disturbance.”

Adding millet to a sorghum crop improves weed control

He has since found that adding millet to a sorghum crop improves weed control. In the wet summer of 2011 he sowed a mixture of millet and sorghum that grew more than two metres tall and produced about 3 t/ha of grain. The crop was harvested in mid April and he sowed the paddock to wheat the next day.

“The rest of the farm had two summer sprays – a knock-down and a pre-emergence spray – to prepare for wheat. We sowed straight into the millet and sorghum paddock, which had stubble a metre high and no summer weed, wire weed or ryegrass.

“The tall summer crop shaded the ground and out-competed the summer weeds. The millet roots bound the soil up so there was no room for more weed roots. “It was an out-of-control paddock the year before, full of ryegrass, which is why we sprayed it out and planted the summer crop. It was nearly clean after the sorghumand millet.

“Some ryegrass came up in the wheat crop and we went in eight weeks later with a post-emergence herbicide, just because I wanted to tidy it up. That was the only

weed control for that paddock for the whole year.

“I spent $50/ha on chemical for the rest of the farm trying to keep it clean.” The roots of the millet and sorghum also improved trafficability.

“A lot of our country was waterlogged because of the wet summer that year and I had to stop sowing the rest of the farm because I was leaving awful, deep tracks and nearly getting bogged. In fact I nearly got bogged on the sand hills driving across to the millet and sorghum paddock, but once I got into that paddock, I only needed two-wheel drive and had zero wheel slip. “The soil was full of millet and sorghum roots, which were holding the soil together.

“It was a real eye opener to get down in that paddock, where I would normally have got bogged in those conditions, and find the soil had the strength to support the machinery due to the root structure.”

“No-till paddocks are definitely 

better for double cropping as they let more

 moisture deeper into the soil ».