In­no­va­tive grow­ers are start­ing to think small in New Zealand – with some im­pres­sive re­sults. An­thony Byrt goes down on the farm with bio-in­ten­sive mar­ket gar­dener Jodi Roe­buck.

North & South - - Contents - BY AN­THONY BYRT

In­no­va­tive mar­ket gar­den­ers are start­ing to think small in New Zealand – with some im­pres­sive re­sults.

Along a wooden bench un­der a trans­par­ent plas­tic roof, trays and trays of tiny plants grow in in­cred­i­ble colours: au­tum­nal reds, trippy pur­ples, and mul­ti­ple depths of green – a minia­ture for­est of peas and ama­ranth and mus­tards. It’s pretty as hell. Tobi, a tall, archety­pally Ger­man 21-year-old trav­el­ling the world to learn about bioin­ten­sive gar­den­ing, ex­plains how the mi­cro­greens set-up works.

The crop grows in a mat­ter of days, he tells me, and a 70g bag goes for $5. The morn­ing’s quick 800g har­vest, then, has yielded about 60 bucks. Then he breaks up a chunk of tray soil and holds it up to me. Thick with roots, it’s per­fect, car­bon-rich ma­te­rial for com­post­ing. Next to the mi­cro­greens, tightly packed tomato plants reach for the roof, cov­ered in fruit. Just be­hind them are cu­cum­bers, climb­ing up wires. Ev­ery space of the makeshift green­house is grow­ing some­thing. Tobi’s boss, Taranaki mar­ket gar­dener Jodi Roe­buck, can’t re­mem­ber the Ger­man name for the to­ma­toes. “Riesen­traube,” Tobi in­tones, per­fectly.

Roe­buck, who’s based just out­side New Ply­mouth, made his name as a restora­tive grazier, tak­ing land where the soil and pas­ture had been ham­mered by over­graz­ing – in­clud­ing the 2.8ha block he and his wife bought in 2004, but mostly other peo­ple’s – and turn­ing it into rich, fer­tile, bio-di­verse pas­ture. By “mob graz­ing” his sheep in­ten­sively in small spa­ces, for a mat­ter of hours or a day at most be­fore mov­ing them on, he slowly trans­formed the land­scape, and the soil qual­ity.

re­li­giously on their farms to get car­bon into the ground quickly: tarp­ing. At any given time in Roe­buck’s gar­den, a solid num­ber of his beds are un­der black tarps. Usu­ally, this is af­ter he’s grown some kind of cover crop. As the cover crop grows, it helps to put nu­tri­ents like ni­tro­gen and car­bon back into the soil through root ex­u­dates. In the win­ter, Roe­buck’s pre­ferred cover crop is oats; in sum­mer, it’s buck­wheat.

When those crops get to a rea­son­able level of ma­tu­rity, Roe­buck chops and drops them in place, then cov­ers the whole bed with a tarp. Without light and with the ex­tra heat gen­er­ated un­der the cover, the plant ma­te­rial starts to de­com­pose quickly. Worms come up to har­vest it and take it back down. The re­sult is a huge in­jec­tion of car­bon in a short time­frame. Af­ter a few weeks – in­stead of the months tied up in con­ven­tional com­post­ing – and with a bit of added ma­nure, the bed is ready for the next veg­etable crop.

In a re­cent con­ver­sa­tion, Roe­buck tells me about a new cover-crop tech­nique he’s us­ing: grow­ing mi­cro­greens in out­door beds rather than a green­house. Twice a week, he sows peas in 3m strips that take 12-14 days to reach mi­cro­green ma­tu­rity. In that time, 25% of the plant’s en­ergy is given off through root ex­u­dates, feed­ing the soil, while the roots them­selves de­velop into that car­bon-rich hu­mus Tobi had so proudly showed me in the green­house.

“It’s ba­si­cally a two-week cover crop,” Roe­buck says, ex­cit­edly. “We make 750 bucks off a bed, we tarp it, and three to five weeks later we’ve got this bed of gold we can then plant back in.”

There’s a big rea­son these guys spend so much time think­ing about car­bon and tin­ker­ing with soil struc­ture: it’s the cru­cial in­gre­di­ent in the qual­ity of their prod­uct, its mar­ketabil­ity, and their even­tual prof­itabil­ity. Car­bon-rich soil re­sults in stronger plants and nu­tri­ent­dense pro­duce, which is health­ier and tastier for con­sumers. Health­ier plants also have much bet­ter in­sect re­sis­tance. The depth of the soil mat­ters too, which is why hav­ing per­ma­nent beds, rather than whole fields that are ploughed be­tween har­vests, is so im­por­tant. Ex­pos­ing soils re­leases soil car­bon; the longer they’re un­cov­ered, the more car­bon is lost. But per­ma­nent beds can be deep­ened and en­riched, while be­ing al­most con­stantly cov­ered.

Both Roe­buck and Fortier swear by the broad­fork as the es­sen­tial tool for this, its long tines aer­at­ing soil and work­ing in or­ganic mat­ter without ac­tu­ally turn­ing the bed over. Deeper soil means plant roots can grow down rather than across. As a re­sult, they aren’t com­pet­ing with each other for nu­tri­ents, and more can grow in a smaller space. And when the plants ma­ture, they cover the en­tire bed, re­duc­ing weed pres­sure and elim­i­nat­ing the need for glyphosate.

There’s a big­ger-pic­ture point about this fo­cus on soil car­bon, too. At the 2015 United Na­tions Cli­mate Change Con­fer­ence in Paris, which led to the Paris Agree­ment, France in­tro­duced the “4 per 1000” ini­tia­tive. Es­sen­tially, this was a pro­posal that all na­tions in­crease their soil-car­bon stocks by 0.4% per year. The key to this is more in­ten­sive plant­ing – grass­lands, pas­ture, forestry, and food crops – not only be­cause the plants them­selves ab­sorb car­bon diox­ide from the at­mo­sphere while they’re grow­ing, but be­cause the or­ganic mat­ter they gen­er­ate

“I don’t be­lieve small farms can feed the world,” Stone tells me. “I’m more of a prag­ma­tist than a lot of peo­ple in this space.”

can be used to se­quester car­bon in soils. And that im­proves soil qual­ity, help­ing to ad­dress one of cli­mate change’s great ex­is­ten­tial threats: food se­cu­rity.

Roe­buck is a huge be­liever in the po­ten­tial of soil-car­bon se­ques­tra­tion and its ef­fects on healthy food pro­duc­tion – it’s a key fac­tor in both his gar­den­ing tech­niques and his sheep graz­ing. “I know farm­ers that are farm­ing 5000 acres [2020 hectares] and se­ques­ter­ing car­bon, with maybe one em­ployee,” he says. “That’s ef­fec­tive. Whereas if we look at feed lots and hard ‘graz­ing’, if we can even call it that, it doesn’t look too good for the planet.”

From an eco­log­i­cal per­spec­tive, then, there’s a lot to com­mend the new bioin­ten­sive mar­ket gar­den, which pri­ori­tises soil car­bon, cover crop­ping, space and wa­ter ef­fi­ciency, and nu­tri­ent den­sity. In New Zealand, it could also start to an­swer one of our ma­jor chal­lenges. Pop­u­la­tion pres­sure is mak­ing land se­ri­ously ex­pen­sive. Farms, or­chards and mar­ket gar­dens are be­ing chopped up and sold in ever-smaller blocks, and of­ten aren’t used for food pro­duc­tion af­ter they change hands. This is a threat in ar­eas with some of our most valu­able food­pro­duc­ing soils, such as Pukekohe. Build­ing over that soil is a trav­esty. If it does hap­pen, at least the bio-in­ten­sive model could partly off­set the pro­duc­tion loss.

How­ever, even its most in­no­va­tive prac­ti­tion­ers are wary of be­ing overzeal­ous. “I don’t be­lieve small farms can feed the world,” Stone tells me. “I’m more of a prag­ma­tist than a lot of peo­ple in this space. I think large farms will feed the world. But we can take the things

Roe­buck har­vests quickly and gets mul­ti­ple cuts from his in­ten­sive let­tuce beds. Ef­fi­ciency is a cru­cial as­pect of his busi­ness model.

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