A poco que baje la merma, habrá menos basura.

A poco que is a fixed expression meaning if only ... a little, as long as ... even slightly, or with even a small change.

So A poco que baje la merma means something like:

• If the waste/shrinkage drops even a little
• As long as the shrinkage goes down a bit
• With even a small reduction in shrinkage

It suggests that only a small decrease is enough for the result in the main clause to happen.

Example pattern:

• A poco que estudies, mejorarás.
  If you study even a little, you’ll improve.

Because a poco que normally introduces a situation that is hypothetical, expected, or conditional, and Spanish usually uses the subjunctive after it.

That is why you get:

• A poco que baje la merma...

and not normally:

• A poco que baja la merma...

Here, baje is the present subjunctive of bajar.

This is similar to other structures where Spanish uses the subjunctive for something not presented as a confirmed fact yet.

Yes, you could say Si baja la merma, habrá menos basura, and it would be grammatical.

But the nuance is slightly different:

• Si baja la merma... = If shrinkage goes down...
  Neutral condition.
• A poco que baje la merma... = If shrinkage goes down even a little...
  Stronger idea that even a small reduction is enough.

So a poco que adds the idea of even a little bit.

Merma refers to a reduction, loss, shrinkage, or wastage, especially in business, production, stock, food handling, or manufacturing contexts.

In Spain, it is often used for:

• loss of product
• spoilage
• shrinkage in inventory
• reduction caused by damage, evaporation, trimming, deterioration, etc.

So it is not just any kind of decrease. It often implies some kind of loss of usable quantity.

Depending on context, merma might be translated as:

• shrinkage
• loss
• waste
• spoilage
• reduction

Because merma here is being treated as a specific, known concept: the shrinkage / the wastage / the loss.

Spanish often uses the definite article where English might not.

So:

• la merma = the shrinkage / the wastage
• la basura = trash / the trash, depending on context

This is very normal in Spanish, especially when talking about general concepts that are already understood in the situation.

Habrá is the future tense of haber used in the sense of there will be.

So:

• habrá menos basura = there will be less trash

The sentence is setting up a result:

• if shrinkage decreases even a little,
• then there will be less trash.

Spanish could also use the present in some contexts:

• A poco que baje la merma, hay menos basura.

But habrá sounds very natural if the speaker is talking about a future consequence or prediction.

Because menos directly modifies the noun basura here.

So:

• menos basura = less trash

You do not use de before a noun in this structure.

Compare:

• menos basura = less trash
• menos comida = less food
• menos problemas = fewer problems

You do use de in other structures, for example with numbers or quantities:

• menos de diez kilos
• menos de la mitad

But before a noun by itself, it is simply menos + noun.

Because basura is often treated as an uncountable / mass noun, just like trash or garbage in English.

So singular is normal:

• menos basura
• mucha basura
• poca basura

If you were talking about individual items, Spanish would use a countable noun instead, such as:

• menos residuos
• menos desperdicios

But basura as a general mass is very natural here.

It is perfectly correct and fairly common, but it can sound a bit more set or structured than very basic everyday language.

You will hear and read it, especially in:

• journalism
• formal speech
• explanation
• argumentation
• written Spanish

In very simple everyday speech, someone might choose:

• si baja un poco...
• con que baje un poco...

But a poco que is absolutely normal and useful to understand.

Yes. It is a general pattern:

• A poco que + subjunctive, ...

Examples:

• A poco que estudies, aprobarás.
• A poco que llueva, se cancela el partido.
• A poco que mejoren las ventas, saldremos adelante.

In all of these, the idea is:

• even a small amount of X is enough for Y to happen.

Yes, the order is natural because the sentence begins with the condition, then gives the result.

Structure:

• A poco que baje la merma = conditional clause
• habrá menos basura = main clause

This is a very common way to organize conditional sentences in Spanish.

You could reverse the order:

• Habrá menos basura a poco que baje la merma.

That is also grammatical, but the original version is often clearer because it presents the condition first.

Yes, they are related but not identical.

• merma refers to the loss/reduction/shrinkage
• basura refers to the physical waste or trash produced

So the idea is something like:

• if there is less loss/shrinkage,
• then less material ends up as trash.

In other words, merma is the process or amount of loss, while basura is the discarded result.