Agricultural plastic mulching is an important horticultural process for increasing crop yields because it preserves soil moisture, soil temperature, and nutrients, and avoids the need for weed herbicides. However, there are risks to using plastic mulch, since residual macroplastic (MaP), microplastic (MP), and nanoplastic (NP) in fields have a significant negative impact on the environment, causing damage to soil properties, harming microorganisms in the soil, and entering the human body via the food chain. Plastic mulch is often disposed of in landfills or used in techniques like the thermal process to gain energy or recycling to generate plastic granules for the plastic industry. Pretreatments are occasionally required before recycling, such as cleaning the mulch from the soil to fit the recycling process. This review provides an overview of the quantities and negative impacts of plastic, especially plastic mulch films after use, as well as their decomposition products, on the environment, soil, and human health, and presents alternatives. The possibilities and problems of collecting and recycling films are discussed in addition to the alternatives, for example, the use of biodegradable films. Overall, agricultural advancements to reduce plastic waste in the environment by using thicker films, collection after use, and recycling in developed countries are on a good path. However, NP poses a risk, as it is still completely unclear how it affects human health. Alternatives to plastic mulch have found little acceptance so far due to the significantly higher material costs.

Mechanical loads cause severe damage to perishable agricultural products. In order to quantify the mechanical impact during harvest and postharvest processes, several electronic fruits have been developed. The objective of the work described here was to compare on a laboratory scale different types of impact acceleration recording electronic fruits: Mikras implanted in a real potato tuber as well as in a dummy tuber, IRD, Smart Spud and TuberLog. The acquisition of mechanical impacts was performed using a drop simulator with optional steel or PVC as impact material as well as a processing line simulator. Our results show that drops from 10 cm height on PVC caused similar peak accelerations of Mikras implanted in a real potato or a dummy, IRD and TuberLog. When dropped onto steel however, IRD, TuberLog and Mikras implanted in a dummy recorded higher peak values than Mikras in real potatoes. Impact on the flat side of a tuber led to higher peak values than impact on the apical region. This could be caused by different elastic compliance of synthetic materials as well as material thickness. Running through the processing line simulator TuberLog recorded the most impact; Smart Spud recorded a low number of impacts compared to the other electronic fruits. In all experiments the least sensitive measurements were recorded using Smart Spud.

The storage of fruit at minimum oxygen condition is crucial for optimal fruit quality maintenance. However, the optimal oxygen partial pressure of fruit varies according to several factors such as species, cultivar, harvest maturity, temperature, growing season and storage period. Based on these factors, storage technologies were developed that allow for the detection of the lower oxygen limit (LOL) and the storage of fruit under the lowest optimal oxygen partial pressure. One emerging technology is known as dynamic controlled atmosphere (DCA). Commercially, there are four DCA systems used: [1] DCA based on ethanol production and accumulation (DCA-Eth); [2] DCA based on chlorophyll fluorescence (DCA-CF); DCA based on the respiratory quotient (DCA-RQ) and [4] DCA based solely on CO2 production (DCA-CD). This reviews the recent developments of these DCA systems and their effect on fruit quality. Generally, the storage of fruit under DCA has a positive effect on the overall fruit quality, with regards to reduced physiological disorders and higher flesh firmness maintenance, when compared to controlled atmosphere (CA). Evidence also shows that storing fruit under DCA-RQ and DCA-CD allowed higher volatile compound emission and concentration, which can contribute positively to fruit flavor. The DCA systems are “green storage technologies” because the system enables the increase of storage temperature and thereby saving electrical energy. Storage of apples under DCA maintains an overall fruit quality similar to CA combined with the ripening inhibitor 1-Methylcyclopropen (1-MCP), which is an interesting option for organic fruit storage. Dynamic controlled atmosphere is a recently developed storage technique and is in constant improvement. The latest developed DCA techniques (DCA-RQ and DCA-CD), in contrast to DCA-CF, allow the use of extremely low oxygen levels. In the future, new and multi-sensor DCA systems are under development, which might not just control O2 partial pressure but also temperature and other parameters to allow for more energy efficient but high quality fruit storage systems.

Apples are stored at temperatures close to 0 °C and high relative humidity (up to 95%) under controlled atmosphere conditions. Under these conditions, the cyclic operation of the refrigeration machine and the associated temperature fluctuations can lead to localized undershoots of the dew point on fruit surfaces. The primary question for the present study was to prove that such condensation processes can be measured under practical conditions during apple storage. Using the example of a measuring point in the upper apple layer of a large bin in the supply air area, this evidence was provided. Using two independent measuring methods, a wetness sensor attached to the apple surface and determination of climatic conditions near the fruit, the phases of condensation, namely active condensation and evaporation, were measured over three weeks as a function of the operating time of the cooling system components (refrigeration machine, fans, defrosting regime). The system for measurement and continuous data acquisition in the case of an airtight CA-storage room is presented and the influence of the operation of the cooling system components in relation to condensation phenomena was evaluated. Depending on the set point specifications for ventilation and defrost control, condensed water was present on the apple surface between 33.4% and 100% of the duration of the varying cooling/re-warming cycles.

In situ, continuous and real-time monitoring of respiration (R) and respiratory quotient (RQ) are crucial for identifying the optimal conditions for the long-term storage of fresh produce. This study reports the application of a gas sensor (RMS88) and a modular respirometer for in situ real-time monitoring of gas concentrations and respiration rates of strawberries during storage in a lab-scale controlled atmosphere chamber (190 L) and of Pinova apples in a commercial storage facility (170 t). The RMS88 consisted of wireless O₂ (0% to 25%) and CO₂ sensors (0% to 0.5% and 0% to 5%). The modular respirometer (3.3 L for strawberries and 7.4 L for apples) consisted of a leak-proof arrangement with a water-containing base plate and a glass jar on top. Gas concentrations were continuously recorded by the RMS88 at regular intervals of 1 min for strawberries and 5 min for apples and, in real-time, transferred to a terminal program to calculate respiration rates ( ${\mathrm{R}}_{{\mathrm{O}}_2}$ and ${\mathrm{R}}_{{\mathrm{CO}}_2}$ ) and RQ. Respiration measurement was done in cycles of flushing and measurement period. A respiration measurement cycle with a measurement period of 2 h up to 3 h was shown to be useful for strawberries under air at 10 °C. The start of anaerobic respiration of strawberries due to low O₂ concentration (1%) could be recorded in real-time. ${\mathrm{R}}_{{\mathrm{O}}_2}$ and ${\mathrm{R}}_{{\mathrm{CO}}_2}$ of Pinova apples were recorded every 5 min during storage and mean values of 1.6 and 2.7 mL kg⁻¹ h⁻¹, respectively, were obtained when controlled atmosphere (CA) conditions (2% O₂, 1.3% CO₂ and 2 °C) were established. The modular respirometer was found to be useful for in situ real-time monitoring of respiration rate during storage of fresh produce and offers great potential to be incorporated into RQ-based dynamic CA storage system.