When does plastic-film mulching yield more for dryland maize on the Loess Plateau of China? A meta-analysis

Authors: WANG, NAIJIANG - Northwest A&f University; DING, DIANYUAN - Northwest A&f University; Malone, Robert - Rob; CHEN, HAIXIN - Northwest A&f University; WEI, YONGSHENG - Northwest A&f University; ZHANG, TIBIN - Northwest A&f University; LUO, XIAOQI - Northwest A&f University; LI, CHEN - Northwest A&f University; CHU, XIAOSHENG - Northwest A&f University; FENG, HAO - Northwest A&f University

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2020
Publication Date: 6/16/2020
Citation: Wang, N., Ding, D., Malone, R.W., Chen, H., Wei, Y., Zhang, T., Luo, X., Li, C., Chu, X., Feng, H. 2020. When does plastic-film mulching yield more for dryland maize on the Loess Plateau of China? A meta-analysis. Agricultural Water Management. 240. https://doi.org/10.1016/j.agwat.2020.106290.
DOI: https://doi.org/10.1016/j.agwat.2020.106290

Interpretive Summary: The Loess Plateau in China is a major source of maize production with variable and limited precipitation across the region, so management practices that conserve water are needed to improve food security. Plastic-film mulching (PM) has been widely adopted for maize production in China to improve yield, especially under water stress conditions. The impact of PM on grain yield depends on the conditions of the study such as climate, management, and soil, but this has not been fully investigated. Data obtained from a large number of peer-reviewed publications were collected to conduct a "meta-analysis" and evaluate maize grain yield increase induced by plastic mulch (GY-I) under 12 different influence factors (climate related variables, soil related variables, and management practices). Results showed that on average, grain yield significantly increased by 56% under under PM compared to no-mulching (NM). The effects of PM on GY-I mainly depended on mean annual precipitation, mean annual temperature, soil texture (particle size), soil bulk density (soil mass per unit volume), plant density (plants per unit area), nitrogen fertilizer rate, and phosphorus fertilizer rate. These results suggest that 1) in general a significant increase in maize yield under PM occurs on the Loess Plateau of China compared to NM and 2) to determine the PM effects on maize yield, the site specific conditions must be considered (climate, soil properties, and field management). This research will 1) help agricultural scientists more fully understand the relationship between application of plastic mulch, maize yield, climate conditions, soil conditions, and management practices and 2) potentially lead to improved food security through development of decision support tools that help optimize agricultural management practices and crop production for site specific conditions.

Technical Abstract: Plastic-film mulching (PM) has been widely adopted for dryland maize (Zea mays L.) on the Loess Plateau of China. However, its impact on grain yield (GY) is variable, so an improved understanding of the factors influencing the PM effects is needed to support evidence-based management decisions. Using the data obtained from peer-reviewed publications (83 studies with 1339 paired observations), we conducted a meta-analysis to evaluate the GY increase induced by PM (GY-I) under different influence factors (climate, soil properties, and management practices). For the controllable influence factors in practice, the optimum conditions for PM application were determined based on the GY-I and GY under PM (GY-P). Results showed that on average, GY significantly increased by 56.10%, from 7345 kg ha-1 under no-mulching (NM) to 10512 kg ha-1 under PM. Among the chosen twelve influence factors, the sample-to-sample variation in the GY-I mainly depended on mean annual precipitation (MAP), mean annual temperature (MAT), soil texture, soil bulk density (SBD), plant density (PD), nitrogen fertilizer rate (NFR), and phosphorus fertilizer rate (PFR). At MAP of 203.8-281.3 mm and MAT of 3.3-4.6 ', PM could increase GY about 1866 kg ha-1, whereas NM had GY of nearly zero. However, the GY-I gradually decreased with increasing MAP and MAT, reaching zero at MAP and MAT of 627.6 mm and 13.1 ', respectively. The GY-I was significantly higher for the silt loam soil than for the loam soil. Increasing SBD, NFR and PFR tended to reduce the GY-I, but the GY-P showed an inverted U-shaped relationship with SBD and changed from increasing to constant with increasing NFR and PFR. As PD increased, the GY-I decreased firstly and then increased, while the GY-P was observed to change oppositely. Given the GY-I and GY-P, it may be advisable to adopt PM at SBD, NFR, PFR, and PD of 1.14-1.30 g cm-3, 160-220 kg N ha-1, 105-135 kg P2O5 ha-1, and 72000-80000 plants ha-1, respectively. These results suggest that in general a significant increase in maize GY under PM occurs on the Loess Plateau compared to NM. However, for optimizing the PM effects on GY, we must consider the local climate, soil properties, field managements in practice, and both GY-I and GY.