Ro­ta­tion ex­plained, with Brian Cal­laghan

Now Brian Cal­laghan’s new al­lot­ment has been cleared, he is mark­ing out the ro­ta­tion ar­eas

Country Smallholding - - Contents - with Brian Cal­laghan

With the main sow­ing and plant­ing pe­riod rapidly ap­proach­ing, it is time to be­gin mark­ing out the ro­ta­tions on my new al­lot­ment. It is time­con­sum­ing and can be dif­fi­cult. Why bother with this?


Dif­fer­ent crops have dif­fer­ent soil fer­til­ity re­quire­ments and group­ing th­ese plants to­gether just makes it eas­ier to pro­vide the fer­til­ity they re­quire in or­der to max­imise growth. Cul­ti­va­tions, grow­ing of green ma­nures, ap­pli­ca­tions of or­ganic mat­ter, and even wa­ter­ing, are all made sim­pler by the use of ro­ta­tions.

Ef­fi­cient feed­ing

Pro­vid­ing just enough food to meet the needs of the crops min­imises wastes of time, en­ergy and other re­sources and helps re­duce pol­lu­tion from run-off of ex­cess fer­tiliser. Mem­bers of the legume fam­ily, for ex­am­ple, have the abil­ity to ‘fix’ some of the ni­tro­gen that is present in nearly 80% of the at­mos­phere and de­posit it in nod­ules at­tached to their roots. This ‘free fer­tiliser’ is then made avail­able to the grow­ing plant and any un­der-sown let­tuce etc, plus residues may also be left for the fol­low­ing crop. Bras­si­cas, on the other hand, are hun­gry for ni­tro­gen and usu­ally fol­low the legumes in a ro­ta­tion to mop up th­ese residues.

Pest and dis­ease con­trol

The in­ter­de­pen­dent work­ing of the nat­u­ral world en­sures that wher­ever a crop is grown for our needs, a food source, or habi­tat, is also pro­vided for less-de­sir­able or­gan­isms such as aphids, slugs, eel­worms, onion rot, club root etc. While out­breaks of aphids and slugs can quickly be brought un­der con­trol, dis­eases such as onion white rot and club root can re­main ac­tive in the soil for decades. With the grad­ual with­drawal of chem­i­cal con­trols for th­ese prob­lems, even con­ven­tional grow­ers are com­pelled to pay close at­ten­tion to bet­ter hus­bandry in the form of ro­ta­tions to help en­sure th­ese prob­lems never de­velop to dam­ag­ing lev­els.

Weed con­trol

Some crops have other ef­fects on the soil that can be utilised to pro­vide bet­ter grow­ing con­di­tions for the fol­low­ing crop. For ex­am­ple, the me­chan­i­cal cul­ti­va­tions in­volved in potato pro­duc­tion and the dense crop canopy it de­vel­ops helps sup­press weed devel­op­ment and leaves the soil in a cleaner con­di­tion than be­fore it was cropped. It fol­lows that crops which often strug­gle with weed prob­lems, such as car­rots, can often ben­e­fit if they are pre­ceded in a ro­ta­tion by ground-clear­ers such as pota­toes.

Ac­cept­ing im­per­fec­tion

Although it is pos­si­ble, in prin­ci­ple, to achieve a per­fect ro­ta­tion, there is no need to be de­spon­dent if it does not run per­fectly to plan. Poor seed ger­mi­na­tion, pest and dis­ease at­tacks, weak growth etc all con­spire to leave un­planned gaps which are often filled with very dis­tant cousins of those that should be in that sec­tion of the ro­ta­tion. Fur­ther, ev­ery year I strug­gle to con­struct a grow­ing plan which can ac­com­mo­date our house­hold pref­er­ence for far more pota­toes than bras­si­cas. De­vis­ing a grow­ing plan which can ac­com­mo­date the dif­fer­ing sized ro­ta­tions leaves me with an an­nual puz­zle I rarely solve. Do the best you can in the cir­cum­stances and leave per­fec­tion for the next world.

Potato fo­liage and cul­ti­va­tions help keep the soil clear of weeds

Time spent re­mov­ing peren­nial weeds now is well spent

Ini­tial cul­ti­va­tions on the four-year ro­ta­tion plan In­set: Brian’s cul­ti­va­tions un­cov­ered some Jerusalem ar­ti­chokes

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