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Hermetia illucens Frass Fertilization: A Novel Approach for Enhancing Lettuce Resilience and Photosynthetic Efficiency under Drought Stress Conditions
Agriculture is faced with the need to reduce mineral fertilizers in order to reduce costs but also to meet political goals. Resilience-enhancing climate change, especially in the face of increasingly frequent and prolonged droughts, has become another issue. The dynamically increasing production of insects for feed and food purposes has become one of the answers to this challenge. This study assesses the fertilizing efficacy effect of frass derived from Black Soldier Fly (Hermetia illucens) production on lettuce (Lactuca L.) growth, including aspects such as yield, photosynthesis activity, photosystem II performance (chlorophyll fluorescence), mineral profile, and antioxidant properties. Additionally, the properties of the soil were assessed by measuring the gas exchange between the soil and the atmosphere. The lettuce plants grew under two water regimes—optimal irrigation and induced drought. The efficiency of frass fertilization was compared with the control and traditional cattle manure. The results indicate that H. illucens frass (HI frass) used as a fertilizer increased the content of essential nutrients in plants—such as potassium and iron. As the dosage of frass increased, the content of vitamin B2 (riboflavin) doubled. The plants that were subjected to drought and properly fertilized showed greater resistance; therefore, a reduction in the synthesis of polyphenolic compounds was observed. Fertilizer had a positive effect on the efficiency of photosynthesis. This study underscores the promising impact of unconventional organic fertilizers, such as H. illucens frass, on enhancing plant performance, especially in challenging environmental conditions. Fertilizers obtained from insect production can be green chemicals in a sustainable food production model.
Hermetia illucens frass improves the physiological state of basil (Ocimum basilicum L.) and its nutritional value under drought
To counterbalance the growing human population and its increasing demands from the ecosystem, and the impacts on it, new strategies are needed. Use of organic fertilizers boosted the agricultural production, but further increased the ecological burden posed by this indispensable activity. One possible solution to this conundrum is the development and application of more environmentally neutral biofertilizers. The aim of this study was to compare the effectiveness of two doses of Hermetia illucens frass (HI frass) with the commercial cattle manure in the cultivation of basil under drought. Soil without the addition of any organic fertilizer was used as a baseline control substrate for basil cultivation. Plants were grown with cattle manure (10 g/L of the pot volume) or HI frass at two doses (10 and 12.5 g/L). The health and physiological condition of plants were assessed based on the photosynthetic activity and the efficiency of photosystem II (chlorophyll fluorescence). Gas exchange between soil and the atmosphere were also assessed to verify the effect of fertilizer on soil condition. In addition, the mineral profile of basil and its antioxidant activity were assessed, along with the determination of the main polyphenolic compounds content. Biofertilizers improved the fresh mass yield and physiological condition of plants, both under optimal watering and drought, in comparison with the non-fertilized controls. Use of cattle manure in both water regimes resulted in a comparably lower yield and a stronger physiological response to drought. As a result, using HI frass is a superior strategy to boost output and reduce the effects of drought on basil production.
How Tillage System Affects the Soil Carbon Dioxide Emission and Wheat Plants Physiological State
The cultivation or ‘tillage’ system is one of the most important elements of agrotechnology. It affects the condition of the soil, significantly modifying its physical, chemical, and biological properties, and the condition of plants, starting from ensuring appropriate conditions for sowing and plant growth, through influencing the efficiency of photosynthesis and ultimately, the yield. It also affects air transmission and the natural environment by influencing greenhouse gas (GHG) emissions potentially. Ultimately, the cultivation system also has an impact on the farmer, providing the opportunity to reduce production costs. The described experiment was established in 1998 at the Brody Agricultural Experimental Station belonging to the University of Life Sciences in Poznań (Poland) on a soil classified as an Albic Luvisol, while the described measurements were carried out in the 2022/2023 season, i.e., 24 years after the establishment of the experiment. Two cultivation methods were compared: Conventional Tillage (CT) and No Tillage (NT). Additionally, the influence of two factors was examined: nitrogen (N) fertilization (0 N—no fertilization, and 130 N–130 kg N∙ha−1) and the growth phase of the winter wheat plants (BBCH: 32, 65 and 75). The growth phase of the plants was assessed according to the method of the Bundesanstalt, Bundessortenamt and CHemische Industrie (BBCH). We present the results of soil properties, soil respiration, wheat plants chlorophyll fluorescence, and grain yield. In our experiment, due to low rainfall, NT cultivation turned out to be beneficial, as it was a key factor influencing the soil properties, including soil organic carbon (SOC) content and soil moisture, and, consequently, creating favorable conditions for plant nutrition and efficiency of photosynthesis. We found a positive effect of NT cultivation on chlorophyll fluorescence, but this did not translate into a greater yield in NT cultivation. However, the decrease in yield due to NT compared to CT was only 5% in fertilized plots, while the average decrease in grain yield resulting from the lack of fertilization was 46%. We demonstrated the influence of soil moisture as well as the growth phase and fertilization on carbon dioxide (CO2) emissions from the soil. We can clearly confirm that the tillage system affected all the parameters discussed in the work.
The influence of Hermetia illucens L. frass on the health, stress, and development of barley
Barley cultivation faces challenges from changing climate conditions, including the increasing threat of drought. This study explored the potential of a fertilizer derived from Hermetia illucens L. frass to enhance the development and health of spring barley under optimal and drought conditions. The experiment, conducted in a controlled greenhouse environment, employed various fertilization treatments, including cattle manure and two doses of H. illucens L. frass-based fertilizer. Comprehensive assessments were made through visual observations and physiological measurements, including chlorophyll fluorescence, leaf gas exchange, and CO2 exchange between the soil and the atmosphere. The results demonstrated that the application of H. illucens L. frass-based fertilizer significantly improved barley vigor and health compared to the control and cattle manure treatments, especially under drought stress. Physiological measurements revealed positive effects on chlorophyll fluorescence parameters, indicating enhanced photosynthetic efficiency. Leaf gas exchange parameters also reflected improved photosynthetic activity, with the H. illucens L. frass-treated plants outperforming others. This study provides valuable insights into the potential of insect-derived fertilizers, particularly H. illucens L. frass, as a sustainable and effective way to enhance crop resilience to drought. As climate change continues to pose challenges to agriculture, incorporating such novel fertilizers may offer a promising avenue for sustainable crop production.
Relay Intercropping of Soybean and Winter Barley in Polish Climatic Conditions—Importance of Strip Width and Yearly Weather
Climate change and the increasing demand for food necessitate innovative agricultural methods. Relay intercropping, where one crop is sown into another already-grown crop, offers a promising alternative to traditional systems. In the 2021/22 and 2022/23 seasons, a field experiment was conducted to assess the relay intercropping of winter barley (Hordeum vulgare L. ssp. polistichon) with soybean (Glycine max (L.) Merr). This experiment took place at the Brody Experimental and Educational Station of the University of Life Sciences in Poznań, Poland. Soybean was sown into designated strips within the barley field, and both crops were cultivated simultaneously until the barley was harvested. After the barley harvest, the soybean plants continued to grow and were harvested at full maturity. The results varied between the two years of this experiment. In the first year, characterized by drought conditions, the soybean yield was completely lost, while the barley maintained a stable yield. In the second year, with more favorable weather, the yields of barley and soybean were interdependent. The use of the relay intercropping system did not increase the Land Equivalent Ratio (LER) above 1. Additionally, total protein yield remained consistent across different cultivation systems. Relay intercropping can serve as a method for protecting crop protein yields under adverse weather conditions and may offer a viable alternative for soybean cultivation in challenging climates.