Phosphorus content and root zone temperature are two major environmental factors affecting maize growth. Both low phosphorus and root zone high temperature stress significantly affect the growth of maize, but the comprehensive effects of phosphorus deficiency and root zone warming are less studied. This study aimed to explore the effects of phosphorus deficiency and root zone warming on the root absorption capacity, total phosphorus content, and photosynthetic fluorescence parameters of maize seedlings. The results showed that maize shoots and roots had different responses to root zone warming and phosphorus deficiency. Properly increasing the root zone temperature was beneficial to the growth of maize seedlings, but when the root zone temperature was too high, it significantly affected the root and shoot development of maize seedlings. The root zone warming had a more significant impact on the root system, while phosphorus deficiency had a greater impact on the shoots. Phosphorus content and root zone warming had a strong interaction. Under the comprehensive influence of normal phosphorus supply and medium temperature in the root zone, the growth of maize seedlings was the best. Under the combined effects of low phosphorus and high temperature in the root zone, the growth was the worst. Compared with the combination of normal phosphorus and root zone medium temperature treatment, the dry mass of the low-phosphorus root zone high temperature treatment was decreased by 55.80%. Under the condition of low-phosphorus too high root zone temperature reduced root vitality, plant phosphorus content, which in turn affected plant growth and light energy utilization efficiency. In the case of sufficient phosphate fertilizer supply, appropriately increasing the soil temperature in the root zone is beneficial to increase the absorption and utilization of phosphorus by plants and promote the growth and development of maize seedlings.

In the context of global warming, the effects of warming in the root zone of crops on maize seedling characteristics deserve research attention. Previous studies on the adaptive traits of dryland maize have mainly focused on soil moisture and nutrients, rather than analyzing potential factors for the adaptive traits of root zone warming. This study was conducted to investigate the effects of different root zone warming ranges on the agronomic traits, hormones, and microstructures of maize seedling roots and leaves. The results showed that minor increases in the root zone temperature significantly enhanced maize seedling growth. However, when the temperature in the root zone was excessive, the stem diameter, root surface area, root volume, total root length, dry matter accumulation, and root/shoot biomass of maize seedlings sharply decreased. Under high temperature stress in the root zone, the root conduit area; root stele diameter; root content of trans-zeatin (ZT), gibberellin A₃ (GA₃), and indoleacetic acid (IAA); leaf thickness; upper and lower epidermis thickness; and leaf content of ZT and GA₃ were significantly decreased. The hormone content and microstructure changes might be an important reason for root growth maldevelopment and nutrient absorption blockage, and they also affected the leaf growth of maize seedlings. Compared with the ‘senescent’ maize type Shaandan 902 (SD902), the plant microstructure of the ‘stay-green’ maize type Shaandan 609 (SD609) was less affected by increased temperatures, and the ability of the root system to absorb and transport water was stronger, which might explain its tolerance of high temperature stress in the root zone.

With the dramatic increased use of agricultural film, the potential environmental risks associated with it have been receiving widespread attention. Biodegradable film (BF) is considered an alternative to conventional polyethylene film (PF), but its feasibility to replace PF needs to be verified. Thus, we conducted a two-year field experiment in the Loess Plateau region of China, exploring the effects of residual biodegradable film and polyethylene film (RBF and RPF) on soil moisture, maize root, and productivity at different residual levels (75 kg ha⁻¹, 150 kg ha⁻¹ and 300 kg ha⁻¹). Regardless of the residual film type, soil water content (SWC), root length density (RLD), and root surface area density (RSD) all decreased with increasing residual level; this phenomenon observed significant differences when the residual level exceeded 150 kg ha⁻¹. Different organs (root and shoot) of maize differed in their sensitivity and sensitivity period to residual film. The two-year degradation rate of RBF was 59.24%, which was higher than that of RPF. Compared to the RPF treatments, the SWC, RLD, RSD, biomass, and root–shoot ratio of the RBF treatments were closer to the no residual film treatment in the second maize growing season. After the two-year experiment, compared to the grain yield, water use efficiency, and precipitation use efficiency of the RPF treatments, that of the RBF treatments increased 0.41–6.24%, 0.12–4.44%, and 0.41–06.24%. The application of BF to replace PF is beneficial to sustainable maize production in dryland, but finding efficient methods to recycle the residual film remains a priority.