Bestandesentwicklung, Erträge und Futterqualitäten verschiedener Maisgemenge mit Stangenbohne, Sonnenblume und Sorghum im Vergleich zum solo angebauten Mais

Abstract

Maize holds significant importance globally and in Germany due to its diverse applications as food, animal feed, and an energy source. The "Ackerbaustrategie 2035" outlines six guidelines for sustainable agriculture, emphasizing maize's central role because of its high yield potential and nitrogen use efficiency. Intercropping with maize is an innovative cultivation method that offers ecological benefits and promises stable yields and greater resilience to environmental stress.The 2023 Common Agricultural Policy (GAP) reform presents new challenges for agriculture, particularly with standards such as GLÖZ 7 and ÖR 2, which focus on crop rotation and legume cultivation, prompting farmers to reconsider their practices. Maize intercropping could be a valuable enhancement in this context, but farmers rely on clear regulations, which are currently inconsistent across federal states. Additionally, satellite remote sensing, intended to monitor climate and environmental measures, faces difficulties in reliably detecting crop mixtures.To assess the advantages and disadvantages of maize intercropping with pole beans, sunflowers, and sorghum, a field trial was conducted in 2023 to examine soil, yield, and quality parameters, compared to monocultures of maize. While maize could be easily mixed and sown with pole beans and sunflowers, intercropping with sorghum posed challenges due to different seed sizes preventing joint sowing in a single seed container. Sorghum may need to be sown using a microgranule tank or in alternating rows.Significant differences in nutrient and water requirements among crops can lead to potential competition among intercropping partners, as demonstrated in this study between maize and sunflower, whereas pole beans and sorghum showed no competitive interaction with maize. Weed management, especially herbicide application, is a challenge in maize intercropping due to limited availability and pre-emergence herbicides. Mechanical weeding is recommended to reduce late-season weed growth.Soil analysis in this study did not show a significant impact of intercropping partners on soil nutrient composition, highlighting the need for long-term studies. The nutrient demands of the crops were reflected in the changes in soil nutrient content from sowing to harvest. A symbiosis with nitrogen-fixing bacteria was not observed in the maize-pole bean intercrop due to high soil nitrogen reserves, which prevented deficiency conditions.Higher fresh biomass yields can be achieved with intercropping compared to maize monocultures, attributed to higher sowing densities. Sunflowers emerged as a strong competitor, negatively affecting fresh biomass yield, plant height, and maize cob weight. The variation in cob weight in intercrops suggests interspecific competition.From a feed analysis perspective, maize-pole bean intercrops were favorable due to significantly higher crude protein, starch, and energy content. In contrast, the maize-sunflower intercrop showed high ash content, low starch and energy levels, and high lignin content, reducing its value for dairy cattle feeding and biogas production. The maize-sorghum intercrop resulted in increased fiber and reduced starch, ELOS, and energy content, negatively affecting quality. All intercrops showed an increase in cations and anions, thus increasing the dietary cation-anion balance (DCAB) compared to maize monocultures. Changes in quality parameters could be attributed to the intercropping partners. The intercropping partners did not significantly affect the ensiling process, as the fermentation acid patterns showed similar trends across all treatments. Biogas yields and methane production were not enhanced with maize intercropping, as the partners had lower values, reducing yields and outputs when combined with maize. The maize-sunflower intercrop was the least efficient in this regard. Further research on maize intercropping is urgently needed to provide farmers with a deeper understanding of its opportunities and risks.