Field Crop 2025, Vol.8, No.5, 247-257 http://cropscipublisher.com/index.php/fc 253 It now appears that using VRS can help farmers use less seeds and still get the same or even better harvests. This is particularly cost-effective for large farms because it can save money and increase production (Loewen and Maxwell, 2024). 8 Challenges and Knowledge Gaps 8.1 Lack of region-specific density recommendations A big problem now is that many places have not yet given recommendations on wheat sowing density suitable for their local areas. In fact, the climate, soil and farming methods in different regions are different. For example, how much sunlight, whether it rains or not, and whether the temperature is high or not, all of these will affect which density is most suitable (Wu et al., 2023). Studies have found that if the density can be adjusted according to local conditions, the yield and resource utilization rate will be greatly improved. But in reality, wheat planting often does not have such "adapting to local conditions" guidance. Farmers can only sow based on experience, which makes it difficult to achieve high yields and good efficiency, and is not conducive to their response to climate change. 8.2 Difficulty in balancing trade-offs between yield and input use efficiency It has always been difficult to achieve high yields without wasting water and fertilizer. Although increasing the density may produce more grain, if it is not managed well, water and fertilizer may be wasted and even pollute the environment (Dong et al., 2020; Zhang et al., 2021). In some high-yield areas of wheat-corn continuous cropping, too much nitrogen fertilizer is often used, resulting in low nitrogen fertilizer utilization and harm to the environment. Currently, only a small number of farmers can achieve high yields without wasting fertilizer (Li et al., 2019; Xu et al., 2023). To strike a good balance, supporting management methods are needed, and farmers should be taught more about how to use fertilizers and how to control water use (Dai et al., 2023). 8.3 Limited long-term studies across crop rotations and seasons Most current studies on seeding density are short-term and focus on only one crop. Such studies cannot reflect the real impacts on soil, water use, and yields over time, such as after several years of rotation (Zhang et al., 2025). Long-term wheat-corn rotation experiments and model analysis have shown that the effects of fertilizer flow and crop sequence between seasons must be considered to achieve stable yields and rational resource use (Cui et al., 2022). However, to truly provide farmers with practical rotation density recommendations, more long-term, cross-crop in-depth studies are needed to see whether these strategies are reliable in different years and different planting methods. 9 Concluding Remarks Choosing the right wheat sowing density is very important, as it affects how well the seedlings grow, whether the leaves shade the wheat properly, and whether more grain can be harvested in the end. Generally speaking, a medium density (e.g., 270 to 300 plants per square meter) works best. This density allows wheat to grow faster, leaves to be better distributed, light and nutrient utilization to be higher, and the final yield to be higher than planting too much or too little. If the density is too high, each seedling will grow weak, the grains will become lighter, and it will be more likely to fall over; if the density is too low, although the seedlings grow strong, the number of ears will not be enough, and the yield will not increase. Therefore, it is particularly important to find the most suitable density. However, different varieties, climates, soils, and management methods have different suitable densities. But as long as the right choice is made, fertilizer, water, and light can be used more efficiently and the yield will be more stable. We should formulate specific sowing density recommendations for different regions and varieties, and also combine them with local climate, soil, and planting methods. Appropriately increasing sowing density and applying less nitrogen fertilizer can also ensure yield while making nitrogen fertilizer more economical and more environmentally friendly. We can try some new methods, such as wide strip planting, combined with density adjustment to improve light utilization and yield. In addition, more long-term research is needed to see how density management affects soil, yield and sustainability under different rotation methods. Using precision agriculture tools such as remote sensing and modeling can also better see how crops are growing, and then adjust the sowing amount according to the differences in plots, making management more flexible.
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