Film mulching technology has greatly improved the efficiency of agricultural production. However, it also causes environmental problems such as soil contamination. Biodegradable mulch films, which represent environmentally friendly alternatives, present different characteristics depending on regional differences and crop growth differences. This review was based on the literature and data collected from databases such as the Web of Science. This study provides a comprehensive overview of the development, types and degradation characteristics of biodegradable mulch films. The following conclusions are presented: (1) Applying biodegradable mulch films can conserve water, maintain the soil temperature, improve soil nutrition, increase the soil respiration rate, and promote soil microbial activity. (2) Biodegradable mulch films promote crop root system development, suppress weeds, shorten the crop growth cycle, improve crop emergence rates, and expand the planting range of crops. (3) At present, the incomplete degradability of biodegradable mulch films, their relatively high cost and the potential harm to soil from their degradation products still limit their widespread use in agricultural production. The aim of this study is to provide a reference for future research and for the application of biodegradable mulch films in the hope of promoting their role in the sustainable development of agriculture.

This paper explores the effects of water and nitrogen management on drip irrigated rice root morphology, nitrogen metabolism and yield, clarifies the relationship between root characteristics and yield formation. Normal irrigation (W₁, 10,200 m³/hm²) and limited irrigation (W₂, 8670 m³/hm², 85% of W₁) were set with nitrogen-efficient variety (T-43) and nitrogen-inefficient variety (LX-3) as the materials. Under the condition of a total nitrogen application rate of 300 kg/hm², three kinds of nitrogen management methods were applied, N₁: a seedling: tiller: panicle: grain ratio of 30%:50%:13%:7%; N₂: a ratio of 20%:40%:30%:10%; and N₃: 10%:30%:40%:20%. Their effects on root morphology, root architecture, and nitrogen metabolism enzyme activities were studied. The results showed, drip irrigated rice yields were highest under W₁N₂, reaching 9.0 t/hm² for T-43 and 7.3 t/hm² for LX-3. Compared with W₂, the root length density (RLD), surface area density (SAD), and root volume density (RVD) of finely branched roots, coarsely branched roots and adventitious roots increased by 49.5%, 44.6%, and 46.7%; the RLD, SAD, RVD, and root architecture RLD β values of the 0–30-cm soil layer increased significantly (p < 0.05); and the yield and nitrogen partial factor productivity increased by 20.7% and 23.3%, respectively, under W₁. Compared with N₁, RLD, SAD and RVD in 0–10 cm soil layer under N2 increased significantly by 24.8%, 35.6% and 31.4%, and RLDβ decreased significantly (p < 0.05); Leaf GS, GOGAT and GDH were increased by 37.9%, 17.0% and 40.9%; all indexes showed a downward trend under N₃. Compared with LX-3, T-43 RLD, SAD, RVD increased significantly (p < 0.05), nitrogen metabolism enzyme activity increased, and yield increased by 21.8%. Rational water and nitrogen management can optimize the root growth and distribution characteristics and achieve simultaneous improvement of rice yield, nitrogen absorption, and nitrogen utilization efficiency under drip irrigation.

Drip irrigation under plastic film mulching is an important technique to achieve water-conserving and high-efficiency rice (Oryza sativa L.) production in arid areas, but the grain yield of drip-irrigated rice is much lower than the expected yield (10.9-12.05 t·hm^-2) in practical production applications. Therefore, we hope to further understand the photosynthetic physiological mechanism of drip-irrigated rice yield formation by optimizing water and nitrogen management during the growth period and provide a scientific reference for improving yield and nitrogen use efficiency (NUE) of drip-irrigated rice in arid areas. In 2020 and 2021, T-43 (a drought-resistant; V1) and Liangxiang-3 (a drought-sensitive cultivar; V2) were cultivated under two water treatments (W₁: limited drip irrigation, 10200 m³·hm^-2; W₂: deficit drip irrigation, 8670 m³·hm^-2) and three nitrogen fertilization modes with different ratios of seedling fertilizer:tillering fertilizer:panicle fertilizer:grain fertilizer (N₁, 30%:50%:13%:7%; N₂, 20%:40%:30%:10%; and N₃, 10%:30%:40%:20%). The photosynthetic characteristics, nitrogen metabolism, yield, and NUE were analysed. The results showed that compared with other treatments, the W₁N₂ resulted in 153.4-930.3% higher glutamate dehydrogenase (GDH) contents and 19.2-49.7% higher net photosynthetic rates (P_n) in the leaves of the two cultivars at 20 days after heading, as well as higher yields and NUE. The two cultivars showed no significant difference in the physiological changes at the panicle initiation stage, but the P_n, abscisic acid (ABA), indole acetic acid (IAA), gibberellic acid (GA₃), and zeatin riboside (ZR) levels of V1 were higher than those of V2 by 53.1, 25.1, 21.1, 46.3 and 36.8%, respectively, at 20 days after heading. Hence, V1 had a higher yield and NUE than V2. Principal component analysis revealed that P_n and GDH were the most important physiological factors affecting rice yield performance. In summary, the W₁N₂ treatment simultaneously improved the yield and NUE of the drought-resistant rice cultivar (T-43) by enhancing the photosynthetic characteristics and nitrogen transport capacity and coordinating the balance of endogenous hormones (ABA, IAA, GA₃, and ZR) in the leaves.

Biodegradable mulch films not only provide similar field benefits to conventional mulch films but also degrade naturally, rendering them an effective alternative to traditional polyethylene mulch films for mitigating “white pollution”. However, recent studies have focused on the material selection and soil ecological impacts of biodegradable mulch films, while their effects on soil water temperature regulation and root architecture in drip-irrigated rice cultivation remain unclear. To address this research gap, in this study, various treatments including no mulch (NM), conventional plastic mulch (PM), and four types of biodegradable mulch films (BM-W₁, BM-B₁, BM-B₂, and BM-B₃) were established, and their effects on the soil hydrothermal flux, root architecture, biomass accumulation, and resource use efficiency of drip-irrigated rice were analyzed at different growth stages. The results indicated the following: (1) Compared with the NM treatment, film mulching increased the soil hydrothermal fluxes and water retention capacity, thereby promoting root growth and biomass accumulation, ultimately increasing the effective panicle number and grain yield. (2) Among the biodegradable film treatments, BM-B₃ (with a degradation period of 105 days) maintained relatively higher soil temperature for a longer duration, which increased surface root distribution in the mid-to-late growth stages, further improving fine root growth and biomass accumulation, consequently enhancing both yield and water use efficiency. In contrast, BM-B₁ and BM-B₂ exhibited excessively rapid degradation rates, leading to significant fluctuations in soil moisture and temperature, thereby negatively affecting water supply and nutrient uptake and ultimately restricting root growth and development. (3) The entropy weight (EW) technique for order of preference by similarity to ideal solution (TOPSIS) model results revealed that although the PM treatment was more advantageous in terms of soil temperature, root dry weight, and soil moisture content, BM-B₃ provided a slightly higher yield than the PM treatment did and offered the advantage of biodegradability, making it a preferred alternative to conventional mulch film. In summary, this study revealed the mechanism by which biodegradable mulch films enhanced biomass accumulation and yield formation in drip-irrigated rice production by optimizing soil hydrothermal dynamics and root architecture, thereby exploring their potential as replacements for conventional mulch films. These findings provide a theoretical basis for the efficient and sustainable production of drip-irrigated rice in arid regions.

The effects of the application of different nitrogen (N) forms via drip-irrigation on the physiological photosynthetic characteristics of rice and their contributions to yield remain incompletely understood. To address this knowledge gap, a field drip-irrigation experiment was conducted from 2020 to 2022 using a high-NUE cultivar (T-43) and a low-NUE cultivar (LX-3). Using a no-nitrogen treatment (CK) as the control, the effects of three nitrogen fertilizer treatments—urea (Urea), ammonium (NH₄⁺), and nitrate (NO₃⁻)—were compared. The main results are as follows. (1) The application of nitrogen significantly increased the biomass (26.74%–30.71%) and yield (40.35%–84.91%). Compared with Urea and NO₃⁻, NH₄⁺ increased the chlorophyll content (Chl) and N metabolic enzyme activity, decreased the abscisic acid (ABA) content, and improved stomatal conductance (G_s). (2) T-43 presented relatively high levels of indole-3-acetic acid (IAA), Chl a + b, and G_s, and a relatively high photosynthetic rate (P_n), whereas LX-3 presented increased ABA levels and reduced Chl a + b, and G_s. (3) Partial least squares path model revealed that under NH₄⁺, IAA was positively correlated with Chl b, G_s, and F_v/F_m, whereas ABA was negatively correlated with Y(II), and Chl a + b. Conversely, the Chl contents decreased, and the ABA and Chl a/b increased in the Urea and NO₃⁻ treatments, thereby increasing the contribution of NH₄⁺ (GoF = 0.714) to yield when compared to the yields in the Urea (0.614) and NO₃⁻ (0.594). In summary, NH₄⁺ synergistically enhances Chl content, photochemical efficiency, antioxidant capacity, and regulates hormone balance while increasing source–sink dry matter accumulation and distribution, thereby achieving efficient production of drip-irrigated rice in arid areas.