The essence of fermentation effect is the efficient metabolic process of aerobic microorganisms, and the flipping depth and uniformity directly determine the three core conditions for microbial survival - oxygen supply, temperature regulation, and material ratio balance. Their impact runs through the entire fermentation cycle, reflected in three key dimensions: maturation efficiency, product quality, and environmental compliance. The specific mechanism and actual effect are as follows:

1、 The influence of flipping depth on fermentation efficiency: determining the aerobic boundary of the fermentation layer and the material metabolism environment

The core function of flipping depth is to control the penetration depth of oxygen and avoid material layering and compaction. Its impact shows a pattern of "both shallow and deep degradation, and optimal depth adaptation":

1. Adaptation of flipping depth (0.8-2.5m, mainstream reasonable range): both fermentation efficiency and maturity are excellent

Adequate and balanced oxygen supply: At a reasonable depth, the flipping device (propeller blade/claw type) can force air into the bottom layer of the material, and the oxygen penetration depth reaches full coverage without obvious oxygen deficient areas. The peak activity of aerobic microorganisms (such as Bacillus and actinomycetes) is maintained at 55-65 ℃, with a fast metabolic rate. The decomposition efficiency of organic materials (cellulose, protein) is increased by more than 30%, and the fermentation cycle is shortened by 5-7 days (compared to shallow flipping).

The temperature field is stable and the sterilization effect meets the standard: sufficient oxygen allows microorganisms to produce heat evenly, and the temperature of the entire layer of the material is stable at 55 ℃ or above and maintained for 7-10 days. It can effectively kill pathogenic bacteria (such as Escherichia coli and Salmonella) and insect eggs (roundworm eggs), with a sterilization rate of over 98%, which meets the "harmless requirements" of the NY525 organic fertilizer standard.

Less layering of materials and sufficient nutrient conversion: The flipping depth covers the entire layer of the fermentation tank, avoiding the stratification phenomenon of "aerobic fermentation in the upper layer and anaerobic fermentation in the lower layer". The carbon to nitrogen ratio (C/N) in the material is uniformly reduced from the initial 25-30:1 to 15-20:1, and nutrients such as nitrogen, phosphorus, and potassium are converted into absorbable states (such as increasing the content of available nitrogen by 20% -25%), making the efficiency of organic fertilizer more stable.

2. Shallow flipping depth (<0.8m): incomplete fermentation, prone to secondary pollution

The lack of oxygen in the bottom layer material triggers anaerobic fermentation: shallow flipping can only disturb the surface 10-30cm material, while the middle and lower layers of material remain in a compacted state for a long time, preventing oxygen from penetrating and forming an anaerobic environment. Anaerobic microorganisms (such as methanogens and sulfate reducing bacteria) proliferate in large numbers, producing harmful substances such as methane, hydrogen sulfide (stinky egg odor), ammonia nitrogen, etc., which not only cause strong odors in organic fertilizers, but also reduce nitrogen retention rates (nitrogen loss reaches 30% -40%).

The temperature cannot meet the standard and the sterilization is not thorough: anaerobic fermentation produces less heat, and the overall temperature of the material is difficult to rise above 55 ℃, or only briefly meets the standard on the surface. Pathogens and insect eggs survive in the deep layer of the material, and there is a risk of "secondary pollution" in the finished organic fertilizer, which may lead to the spread of crop diseases after use.

Extended fermentation cycle and low production efficiency: The anaerobic metabolism rate is only 1/10-1/5 of aerobic metabolism, and the fermentation cycle needs to be extended by 10-15 days during shallow flipping. When the surface material has already decomposed, the bottom layer is still in an unfermented state, resulting in a large difference in overall maturity and a product qualification rate of less than 70%.

3. When the flipping depth is too deep (>3m, without customized design): compaction, oxygen deficiency, and energy waste

Material compaction leads to deep oxygen deficiency: When the flipping depth exceeds the design limit of the equipment, the self weight of the upper material will compact the lower layer, making it difficult for the flipping device to effectively transport oxygen to the bottom layer. Instead, due to the increase in material density, the diffusion resistance of oxygen increases, forming a three-layer imbalance state of "deep anaerobic, middle anoxic, and surface aerobic", resulting in a sharp decrease in fermentation uniformity.

Energy consumption skyrockets, fermentation costs increase: Deep flipping requires a higher power motor drive, with unit energy consumption increasing from 0.3-0.5 kWh/ton to 0.8-1.0 kWh/ton, resulting in an increase of over 60% in energy consumption costs. Moreover, the flipping effect has not improved synchronously, which is considered as "ineffective energy consumption".

Accelerated equipment loss and increased risk of failure: Deep material resistance is high, and the impact and wear on components such as blades and main shafts are doubled, which can easily lead to blade deformation, motor overload and shutdown, indirectly causing interruption of the fermentation process and further affecting fermentation stability.

Key adaptation logic: Depth needs to match material characteristics and fermentation processes

High humidity materials (moisture content 65% -75%): need to be slightly shallower (0.8-1.5m) to avoid deep compaction and water accumulation, and improve breathability;

High fiber materials (straw proportion>30%): can be deepened appropriately (1.5-2.5m), taking advantage of the looseness of straw to avoid compaction, while increasing oxygen storage space;

Tank fermentation process: Underground fermentation tanks can be adapted to deeper depths (2.0-2.5m), while semi underground tanks need to be controlled at 1.5-2.0m to avoid material overflow or incomplete flipping.

2、 The influence of flipping uniformity on fermentation efficiency: determining the consistency of microbial metabolic environment

The uniformity of flipping and throwing includes two core dimensions - material mixing uniformity (carbon nitrogen ratio, moisture, particle size balance) and aeration uniformity (oxygen distribution balance), which are directly reflected in the stability of the fermentation cycle and the uniformity of the finished product quality

1. Excellent flipping uniformity: efficient fermentation and product compliance

Carbon nitrogen ratio is balanced with water content, and microbial activity is consistent: uniform flipping can fully mix animal manure (high nitrogen), straw (high carbon), and auxiliary materials (such as microbial agents and conditioners), ensuring a stable carbon nitrogen ratio of 25-30:1 (aerobic microbial range) for the entire tank material, uniform water distribution (60% -65%), no local "nitrogen excess" or "carbon excess", and no "dry area" or "water accumulation area". Microbial metabolism rate is consistent, and fermentation cycle fluctuations are ≤ 2 days.

Uniform aeration, no anaerobic dead corners: When uniformly flipped, the material particles are fully crushed (particle size ≤ 20mm), the porosity is increased by more than 30%, oxygen can penetrate evenly to every part of the material, avoiding "local anaerobic fermentation", reducing the production of harmful gases such as hydrogen sulfide and ammonia nitrogen, reducing organic fertilizer odor by 70%, and increasing nitrogen retention rate by 25% (reducing ammonia volatilization loss).

The temperature field is uniform, and the maturity and sterilization effect meet the dual standards: uniform aeration allows microorganisms to produce heat evenly, and the temperature of the entire tank is maintained in the range of 55-65 ℃ for a duration of ≥ 7 days. It can not only completely kill pathogenic bacteria and insect eggs, but also fully degrade difficult to decompose organic matter (such as lignin and cellulose) in the material, with uniform maturity (germination index ≥ 85%), no "mixed raw materials" in the finished organic fertilizer, and meets the requirements of "organic matter content ≥ 45%, total nutrients ≥ 5%" in the NY525 standard. The product qualification rate is over 98%.

2. Poor flipping uniformity: fermentation imbalance, poor product quality

Local metabolic environment imbalance, prolonged and unstable fermentation cycle:

There are many anaerobic dead corners, and environmental and product quality risks coexist:

Material waste and increased production costs: Poor uniformity leads to some materials not being fully decomposed, requiring rework and heavy fermentation, resulting in a 10% -15% increase in material loss rate; Meanwhile, extending the fermentation cycle will occupy the fermentation tank space, reduce equipment utilization, and indirectly increase production costs.

Key impact logic: Uniformity is the core prerequisite for "standardization" of fermentation

In the production of organic fertilizers, "uniformity" directly determines the stability of product quality - for B-end customers (such as planting bases and agricultural material distributors), the uniformity of indicators such as maturity, nutrient content, pH value, etc. of finished organic fertilizers is the core demand of procurement, and the uniformity of flipping is the key to achieving this demand: poor uniformity can lead to large fluctuations in product indicators, which cannot meet the standardized fertilization needs of large-scale planting and directly affect the market competitiveness of enterprises.

3、 The synergistic effect of flipping depth and uniformity: fermentation optimization effect with 1+1>2

The flipping depth and uniformity do not act independently, but together determine the "ceiling" of fermentation effect:

If only the depth meets the standard but the uniformity is poor: deep materials will still form anaerobic zones due to uneven mixing and insufficient aeration, greatly reducing the fermentation effect;

If only the uniformity is excellent but the depth is insufficient: the utilization rate of the fermentation tank is low, and the bottom material is deprived of oxygen for a long time, the overall fermentation efficiency cannot be improved;

During collaborative optimization, a reasonable depth (0.8-2.5m) provides a spatial foundation for uniform flipping, and uniform flipping (crushing+mixing+aeration integration) allows materials within the depth range to be in a metabolic environment, achieving a comprehensive optimization effect of "shortening fermentation cycle by 5-7 days, increasing maturity by 25%, nitrogen retention rate by 20%, and product qualification rate of over 98%".

4、 Optimization suggestions in actual production (combined with equipment characteristics)

Deep adaptation: Adjust the flipping depth according to the moisture content and fiber content of the material (shallow throwing for high humidity materials, deep throwing for high fiber materials), to avoid exceeding the equipment design limit (conventional models ≤ 2.5m, customized models can reach 3m);

Uniformity improvement: Choose a combination of propeller blades and claw type flipping device, paired with a variable frequency walking system (speed 0.2-1.5m/min), to ensure sufficient material crushing and uniform mixing during flipping;

Intelligent control: using models with temperature/oxygen sensors to monitor the environment inside the fermentation tank in real time, and adjust the flipping depth, walking speed, and frequency in a coordinated manner to avoid local hypoxia or temperature imbalance;

Material pretreatment: Before flipping, crush the material to ≤ 50mm and adjust the carbon nitrogen ratio to 25-30:1 to lay the foundation for uniform flipping and deep flipping.

summary

The depth of flipping determines the "aerobic boundary" of fermentation, while uniformity determines the "environmental consistency" of fermentation. Both factors directly affect the activity of aerobic microorganisms by influencing the three core conditions of oxygen, temperature, and material ratio, determining the fermentation cycle, maturity, product quality, and environmental compliance. For organic fertilizer production enterprises, choosing a trench type turner with "adjustable depth and strong uniformity" (such as models with modular blades and intelligent control systems) and optimizing the turner parameters based on material characteristics is the key to achieving efficient, stable, and environmentally friendly fermentation, as well as the core path to enhance product competitiveness and reduce production costs.