Field Crop 2025, Vol.8, No.5, 247-257 http://cropscipublisher.com/index.php/fc 250 4 Influence on Final Yield Components 4.1 Effects on number of spikes per unit area The higher the sowing density, the more wheat ears per square meter. Many studies have found that this is true for different varieties and different environments. When too few seeds are planted, the number of ears and yield are low; at medium or slightly higher density, the number of ears is large and the yield is the highest (Tian et al., 2025). But planting too densely is not a good thing. Competition is too fierce, and some tillers do not produce ears. Instead, they grow in vain, wasting nutrients, so the number of ears may not continue to increase (Kondić et al., 2017). 4.2 Grain number and grain weight variations As the sowing density increases, the number of ears increases, and the number of grains naturally increases. However, this may make each grain lighter. Studies have shown that there is often a trade-off between the number of grains and the weight of grains: the more grains there are, the greater the proportion of small grains may be, which lowers the average grain weight (Acreche and Slafer, 2006; Xie and Sparkes, 2021). This phenomenon is affected by the variety and environment, and it is not only reflected in the whole plant, but also in the spikelets. Therefore, if you want a high yield, you must not only consider the number of grains, but also make sure that the grains are heavy enough and the density is just right (Li et al., 2016). 4.3 Harvest index and total biomass accumulation The harvest index (HI) is the ratio of how much dry matter a plant distributes to its grains. The right density allows more nutrients to enter the ear, rather than being wasted on leaves and stems. When the density is higher, the total dry matter may be higher, but each plant may get less, and the grain weight may also decrease (Rivera-Amado et al., 2019). If the plant can deliver more nutrients to the ear during the flowering period, the fruit set rate will be high, the HI will be high, and the yield will be good. However, if the plant is planted too densely, the nutrients produced by photosynthesis are not enough for filling, and the HI will be lowered (Gao et al., 2025). Therefore, if you want to harvest more grain, you have to find a balance between density and nutrient distribution, so that dry matter can be accumulated more and distributed reasonably, and finally more and heavier grains can be produced. 5 Environmental and Management Interactions 5.1 Soil fertility and nutrient availability interactions with density Soil fertility and fertilization methods affect the effect of sowing density on wheat growth. If the soil is not good and there is not enough fertilizer, planting too densely is not good. To improve this situation, organic fertilizers can be used together with chemical fertilizers, such as adding some manure or biochar, so that the soil is looser and has more nutrients, and the wheat roots grow better (Kumari et al., 2024; Ahmad et al., 2025). A strong root system is particularly important, especially in places with poor soil fertility, as it can help absorb more nutrients. And the fertilization method should not be random. A more balanced fertilizer management can make the soil and climate work better together and increase yields. But if you only focus on one type of fertilizer, it may be counterproductive (Wang et al., 2016). 5.2 Effects of climatic factors (e.g., temperature, rainfall) Climate conditions, such as temperature, rainfall, and water availability, can also affect the effect of wheat planting density. Many years of follow-up studies have found that climate can cause large fluctuations in yield, but this effect can be smaller if fertilizers and management methods are kept up (Wei et al., 2021). For example, drought weather often makes high-density planting less effective. But some methods, such as inoculating arbuscular mycorrhizal fungi (AMF), can improve water use efficiency and grain filling in drought and low density (Duan et al., 2023). However, if there is a lot of water, such treatments may not help at high density, and may even have a counterproductive effect. Therefore, different regions must be managed according to actual conditions in order to cope with the problems caused by climate change (Wójcik-Gront et al., 2024). 5.3 Influence of agronomic practices (e.g., row spacing, irrigation) How to set the row spacing, how to irrigate, and how to apply fertilizers will also affect the performance of wheat together with the sowing density. If the row spacing and watering are arranged properly, the roots can grow deeper
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