Journal of Energy Bioscience 2024, Vol.15, No.6, 368-377 http://bioscipublisher.com/index.php/jeb 371 prevention. Pollen beetles have developed widespread resistance to the main insecticides currently used - pyrethroids - which increases the urgency of finding alternative control strategies (Yang et al., 2020; Das et al., 2023). In the past decade, researchers have made great progress in understanding the parasitic wasps, predators and pathogens involved in pest biological control, and how to incorporate biological control into integrated pest management systems. The use of economic thresholds, crop monitoring, and computer-based decision support systems can more effectively target pesticides in time and space. “Push and pull” strategies are being developed to use host plant preferences and their behavioral responses to pheromones to influence the distribution of pests and natural enemies on crops. In addition, natural enemies can be protected by changing crop cultivation practices in the field, and vegetation diversity in agricultural ecosystems can be promoted through habitat and environmental adjustments at the landscape scale, such as planting hedgerows, cover crops, flowering protective headlands, and field edges to provide shelter, food, overwintering sites, and alternative prey or hosts for natural enemies (Zhang et al., 2020). 4 Case Study: Implementing Precision Agriculture for Rapeseed Yield Optimization 4.1 Background and selection of study area Rapeseed yields have increased rapidly in recent decades, and given this development trend, a question is how to promote yield growth through integrated nitrogen fertilizer management strategies. The economic benefits of winter rapeseed cultivation mainly depend on the available seed yield and, to a lesser extent, on oil content. The yield formation process varies greatly and depends on genetic, environmental and agronomic factors and their interactions. The yield potential of a crop is a theoretical assessment of the maximum yield that a high-yielding biological material can produce when grown under optimal physicochemical conditions (Almasi et al., 2019; Esmaeilpour-Troujeni et al., 2021). 4.2 High-density planting for increased yield Although manual transplanting of strong seedlings at low planting density accounts for a large proportion of conventional rapeseed production, high-density planting is impossible in this model, owing to the heavy workload. With the current increase of mechanization in rapeseed production, manual transplanting has been much reduced because of the scarcity of labor. Direct sowing makes the planting density uncontrollable under variable soil conditions. For this reason, high-density planting tends to be common owing to the impracticality of seedling thinning. Besides increasing plant leaf area index and light energy use efficiency, high-density planting can improve nitrogen use efficiency, promote the transformation of nitrogen to grain, and thus increase yield. High-density planting can also improve the uniformity of the rapeseed population, making stems thinner, branches shorter, and maturation more synchronized, leading to marked reductions in seed loss during mechanical harvesting and increased oil content (Lovasz et al., 2023). Several studies have shown that rapeseed was more likely to achieve high yield in high-density plantings. The optimum planting density is usually 30~60×104 plants/ha. The highest yield was achieved at a plant density of 45×104 plants/ha in combination with a narrow row spacing of 15 cm. Rapeseed breeding for high planting density should focus on increasing silique density and number of siliques on the main inflorescence, as well as number of siliques per plant and seeds per pod (Esmaeilpour-Troujeni et al., 2021; Zhang et al., 2020). 4.3 Measured improvements in oil yield and resource efficiency The implementation of these precision agriculture technologies has significantly improved oil yield and resource utilization efficiency. For example, under optimized conditions, the yield was increased by 24.55% by reducing the consumption of irrigation water, electricity and fungicides while increasing the use of chemical fertilizers and farmyard manure. Rapeseed yield ranged from 13.3 to 47.0 q/ha, and oil yield ranged from 629.8 to 2 130.8 L/ha, with the effect of high-dose fertilizer application being statistically significant. These improvements are also reflected in sustainability indicators, with the comprehensive degree of perfection (CDP) and renewability index (RI) increasing to 2.75 and 0.81, respectively, under optimal conditions (Figure 2) (Lovasz et al., 2023; Esmaeilpour-Troujeni et al., 2021; Zhang et al., 2019).
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