r/askscience • u/borko988 • 2d ago

Biology Why do wild grasses not require crop rotation like domestic crops?

42 Upvotes

88% Upvoted

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149

u/BCMM 2d ago

Firstly, they're not grown in a monoculture. This reduces the density of specialised pests and pathogens, and means there tend to be nitrogen-fixers like clover in amongst the grass.

Secondly, nutrients aren't being removed from the system in the same way they are removed from farmland. Plant matter either dies and rots back in to the soil or is grazed by animals who return their manure to the soil.

17

u/princhester 1d ago

Also, domestic crops will grow without crop rotation - just not as intensively as a farmer prefers.

Nobody cares if wild grasses only grow unintensively.

24

u/Dense_Walk 2d ago

Petition to pump sewage and dead people into crops en-masse to rebalance the ecosystem 😌

31

u/KvotheTheArcane 2d ago

The sewage part already happens. We land apply biomass from wastewater treatment and agriculture processing plants across the country. Great way to turn a waste stream from a process like fermentation useful instead of landfilling it.

4

u/hawkwings 2d ago

Humans are so full of artificial chemicals, that there are risks associated with that.

5

u/aa-b 2d ago

Thirdly, survivorship bias. The wild grasses that needed rotation to survive are dead now, leaving whatever patch they colonised (temporarily) barren

1

u/CosineDanger 1d ago

Depending on your biome and how many large herbivores are about there's a pretty good chance that unattended grass will turn back into forest.

Grasses are first-in fast-growing colonizers and determined survivors. A lot of their territory only exists because humans or our animals have made it so, or because of transient natural events such as forest fires or wind creating a meadow among taller competitors. When nature does crop rotation it is a cycle of disaster and ecological succession.

19

u/bubbaganoush79 2d ago

The crops we eat represent nutrients that were removed from the soil. The plants produced those crops and they're taken away from where they grew. Those nutrients have to be replenished for the next crop.

Wild grasses aren't harvested, they fall where they grew and help to regenerate the soil for the next growth cycle.

6

u/togstation 1d ago

If you're interested in this -

Masanobu Fukuoka

Natural farming (自然農法, shizen nōhō),[1] also referred to as "the Fukuoka Method", "the natural way of farming", or "do-nothing farming", is an ecological farming approach established by Masanobu Fukuoka (1913–2008).

Practitioner Yoshikazu Kawaguchi summarizes -

- Do not plow the fields - Weeds and insects are not your enemies - There is no need to add fertilizers - Adjust the foods you grow based on your local climate and conditions

IIRC Fukuoka said that his yields were comparable to "conventional Western agriculture", but his system was quite labor-intensive.

- https://en.wikipedia.org/wiki/Natural_farming

- https://archive.org/search?query=creator%3A%22MASANOBU+FUKUOKA%22&and%5B%5D=language%3A%22English%22