| Effects of water and nitrogen regulation on growth and radiation utilization of alfalfa and Bromus inermis Leysis. mixed cropping grassland |
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| DOI：10.7606/j.issn.1000-7601.2023.02.19 |
| Key Words: mixed forage water and nitrogen regulation dry matter accumulation radiation use efficiency |
| Author Name | Affiliation | | WANG Aixia | College of Water Conservancy and Hydropower Engineering of Gansu Agricultural University, Lanzhou, Gansu 730070, China | | QI Guangping | College of Water Conservancy and Hydropower Engineering of Gansu Agricultural University, Lanzhou, Gansu 730070, China | | YIN Minhua | College of Water Conservancy and Hydropower Engineering of Gansu Agricultural University, Lanzhou, Gansu 730070, China | | KANG Yanxia | College of Water Conservancy and Hydropower Engineering of Gansu Agricultural University, Lanzhou, Gansu 730070, China | | MA Yanlin | College of Water Conservancy and Hydropower Engineering of Gansu Agricultural University, Lanzhou, Gansu 730070, China | | WANG Jinghai | College of Water Conservancy and Hydropower Engineering of Gansu Agricultural University, Lanzhou, Gansu 730070, China | | JIA Qiong | College of Water Conservancy and Hydropower Engineering of Gansu Agricultural University, Lanzhou, Gansu 730070, China | | TANG Zhongxia | College of Water Conservancy and Hydropower Engineering of Gansu Agricultural University, Lanzhou, Gansu 730070, China | | JIANG Yuanbo | College of Water Conservancy and Hydropower Engineering of Gansu Agricultural University, Lanzhou, Gansu 730070, China |
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| Abstract: |
| To solve the problems of extensive production management of artificial grassland and insufficient utilization of climatic resources in inland arid areas of China, a reasonable pattern of forage planting, water and nitrogen supply was employed to fully explore the production potential of regional forage. Triennial (sown in 2018) alfalfa (referred to as ‘alfalfa’) and Bromus inermis Leysis. were used to analyze planting patterns (alfalfa and Bromus inermis Leysis. mixed: D1; Bromus inermis Leysis. single: D2), nitrogen application (low N1: 60 kg·hm-2; high N2: 120 kg·hm-2) and irrigation amount on forage leaf area index (LAI), dry matter accumulation, cumulative interception of photosynthetically active radiation (CIPAR), radiation use efficiency (RUE), yield (Y), water consumption (ETa) water use efficiency (WUE) and nitrogen partial factor productivity (PFPN). The irrigation amount was measured using percentage of the lower limit of irrigation to the field water holding capacity θf, with adequate irrigation (75% to 85% θf) at the branching stage, mild water deficit W1 of 65% to 75% θf, moderate water deficit W2 of 55% to 65% θf, and severe water deficit W3 of 45% to 55% θf at the budding and first flowering stage, and the upper limit of irrigation was 85% θf. The results showed that: (1) The LAI and dry matter accumulation of forage grass increased with the increase of irrigation and nitrogen application. With the advance of growth period，LAI increased rapidly first and then slowly increased or decreased. Dry matter accumulation increased rapidly first and then increased slowly. (2) Both irrigation and N application promoted the accumulation of photosynthetically active radiation interception in forage. Compared with W1N1 treatment, W1N2 increased by 6.38%, W1N1 increased by 15.82% when comparing with W3N1 treatment. And the amount of N application was positively correlated with the RUE of forage grass, and the amount of irrigation was positively correlated with the RUE of mixed forage grass, while the opposite was true for unicasted forage. (3) The increase of irrigation and nitrogen application increased forage yield. Of which W1N2 treatment reached the maximum forage yield, with mixed and unicasted yields of 26 050.73 kg·hm-2 and 12 186.10 kg·hm-2, respectively. While the increase of irrigation reduced water use efficiency, W1 was 2.05% to 8.16% smaller than other treatments. And the increase of nitrogen application reduced the partial productivity of nitrogen fertilizer, N2 was 9.68% to 46.42% smaller than other treatments. (4) Compared with Bromus inermis Leysis, respectively, the LAI, dry matter accumulation, CIPAR, RUE, WUE and PFPN of mixed forage increased by 132.62%, 112.93%, 49.27%, 45.34%, 88.76% and 111.55%, respectively. Alfalfa mixed with Bromus inermis Leysis. combined with mild water deficit (lower limit of irrigation 65%~75% θf) and higher N application (120 kg·hm-2) significantly improved forage biomass and radiation use efficiency. |
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