The prolonged effect of film mulch and P application on lucerne forage yield in a semiarid environment

Meng Kong; Yan-Jie Gu; Cheng-Long Han; Xiao-Peng Shi; Jing Kang; Kadambot H M Siddique; Feng-Min Li; Zi-Qiang Yuan

doi:10.3389/fpls.2023.1331704

The prolonged effect of film mulch and P application on lucerne forage yield in a semiarid environment

Front Plant Sci. 2023 Dec 11:14:1331704. doi: 10.3389/fpls.2023.1331704. eCollection 2023.

Authors

Meng Kong^{1

2

3}, Yan-Jie Gu^{3

4}, Cheng-Long Han^{3

4}, Xiao-Peng Shi³, Jing Kang³, Kadambot H M Siddique⁵, Feng-Min Li^{3

6}, Zi-Qiang Yuan³

Affiliations

¹ Shanxi Province Key Laboratory of Sustainable Dryland Agriculture, Shanxi Institute of Sustainable Dryland Agriculture, Shanxi Agricultural University, Taiyuan, Shanxi, China.
² Key Laboratory of Sustainable Dryland Agriculture (Co-construction by Ministry of Agriculture and Rural Affairs and Shanxi Province), Shanxi Agricultural University, Taiyuan, Shanxi, China.
³ State Key Laboratory of Herbage Improvement and Grassland Agroecosystems, College of Ecology, Lanzhou University, Lanzhou, Gansu, China.
⁴ State Key Laboratory of Plateau Ecology and Agriculture, Department of Grassland Science, College of Agricultural and Husbandry, Qinghai University, Xining, Qinghai, China.
⁵ Institute of Agriculture, The University of Western Australia, Perth, WA, Australia.
⁶ Jiangsu Collaborative Innovation Center for Modern Crop Production co-sponsored by Province and Ministry, College of Agriculture, Nanjing Agricultural University, Nanjing, China.

Abstract

Introduction: Limited water and soil phosphorus (P) availability often hampers lucerne productivity in semiarid regions. Plastic film mulch and P application typically enhance young lucerne (2-3 years) productivity by increasing soil water use and P availability. However, the prolonged impact of film mulch and P application on lucerne productivity as the stand ages remains unclear.

Methods: This study conducted a 9-year field experiment on the semiarid Loess Plateau to investigate how film mulch and P application affect lucerne forage yield, soil water content, and soil fertility. The field experiment used a split-plot design with randomized blocks, in which the whole plots were with (M1) and without plastic film mulch (M0), and the split plots were four P rates (0 (P0), 9.7 (P1), 19.2 (P2), and 28.8 (P3) kg P ha^-1).

Results and discussion: The M1 treatment produced significantly higher lucerne forage yields than the M0 treatment during the first five years, but the yield-increasing effect of film mulch gradually diminished over time, with no effect in Years 6-8, and lower yields than the M0 treatment in Year 9. Phosphorus fertilization significantly increased forage yield after Year 3 in the M0 treatment, but only in Years 3-5 in the M1 treatment. In Years 2-5, film mulch significantly increased soil organic carbon, total nitrogen (N), inorganic N, and microbial biomass carbon in P0, P1, and P2 but not in P3. However, in Years 7-9, film mulch significantly decreased soil available potassium (K), organic carbon mineralization, lucerne density, and shoot K concentration, but did not reduce soil N and P availability at any level P of application. Moreover, plastic film mulch significantly increased the soil water content at 0-300 cm deep from Year 7 onwards. In conclusion, film mulch ceased to enhance lucerne production beyond year 6, which could not be attributed to soil water content, N or P availability but was partially associated with reduced soil K availability. Consequently, future research should focus on soil K availability, and K addition should be considered after five years in lucerne pastures mulched with plastic film in semiarid areas.

Keywords: film mulch; legume forage; loess plateau; phosphorus application; soil fertility; soil water deficit.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was supported by the Fundamental Research Program of Shanxi Province (No. 202203021212473), the Doctoral Scientific Research Start-up Foundation of Shanxi Agricultural University (2021BQ47), the Program of Doctoral Research Foundation of Shanxi Province (No. SXBYKY2021087), the ‘111’ Program (BP0719040), and Gansu Province Science and Technology Foundation for Youths (21JR7RA516).