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| DOI：10.13522/j.cnki.ggps.2020069 |
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| Optimal Fertigation and Irrigation for Sweet Sorghum Production in Arid Regions in Northwest China |
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SI Rui, LIU Bing, ZHU Zhaocen, LIU Chan, ZHAO Ying
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1. Linze Inland River Basin Research Station, Chinese Ecosystem Network Research, Key Laboratory of Ecohydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences, Lanzhou 730000, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China
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| Abstract: |
| 【Background】Sweet sorghum has emerged as a crop with multiple usage ranging from feeding animals to being used for biofuel to sugar production. The large diurnal temperature variation in arid areas in northwest China is suitable for sweet sorghum growth, and its marginal lands including saline-alkali lands and sandy lands have become a main sweet sorghum production base in China. However, there is a lack of understanding about its optimal fertilization and irrigation.【Objective】This paper is to fill this gap by experimentally studying how irrigation and fertilization combine to affect growth and yield of sweet sorghum in these regions.【Method】The experiment was conducted in a desert oasis on the edge of Hexi corridor. It compared three irrigation amounts: 6 000 m3/hm2 (W1), 7 200 m3/hm2 (W2) and 8 400 m3/hm2 (W3), and three nitrogen fertilizations (N-P2O5-K2O with mass fractions of N, P and K all being 15%): 450 kg/hm2 (F1), 600 kg/hm2 (F2) and 750 kg/hm2 (F3). Overall, there were nine treatments which were arranged randomly in the field. In each treatment, we measured the growth traits and ultimate yield of the sorghum.【Result】①The irrigation amount did not show significant effects on plant height, stem thickness and biological yield, but the fertilization did, with irrigation and fertilization combining to affect plant height and biological yield at significant level. ②W1F3 was optimal in terms of increasing plant height (to 333.1cm), stem thickness (to 22, 63 cm), biological yield (to 29.35 t/hm2) and water productivity (to 3.80 kg/m3), where were 12.16%, 11.29%, 30.82% and 87.19% up, respectively, compared to those in W3F3; its associated yield income, net income and production-to-investment ratio was 26 418.84 Yuan/hm2, 15 850.73 Yuan/hm2 and 2.50% respectively, increasing by 30.84%, 88.17% and 45.35%, compared with that in W3F3. ③Plant height, stem thickness, the number of internodes and leaves, leaf dry mass, stem dry quality, ear dry quality and stalk juice sugar hammer were all positively correlated with biological yield. In addition to juice yield, other traits including the stem thickness, plant height, leaf number and stem quality, were also found to positively affect biological yield.【Conclusion】Irrigation of 6 000 m3/hm2 coupled with 750 kg/hm2 of nitrogen fertilization is optimal for growth and ultimate yield of the sweet sorghum in northwestern China. |
| Key words: sweet sorghum; growth traits; biological yield; irrigation water productivity; partial fertilizer productivity; economic benefits |
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