Nitrogen forms affect root growth,photosynthesis, and yield of tomato under alternate partial root‐zone irrigation |
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Authors: | Chu Chen Fei Xu Ji‐Rong Zhu Rong‐Fu Wang Zhi‐Heng Xu Liang‐Zuo Shu Wen‐Wen Xu |
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Affiliation: | 1. Anhui Key Laboratory of Resource and Plant Biology, College of Life Sciences, Huaibei Normal University, Huaibei 235000, P.R. China;2. College of Life Sciences, Anhui Agriculture University, Hefei 230036, P.R. China |
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Abstract: | To increase efficiency of water and nitrogen (N) fertilizer use, this study was conducted with a split‐root pot experiment to investigate the effects of different forms of N fertilizer on root growth, photosynthesis, instantaneous water use efficiency (IWUE), and yield of tomato (Lycopersicon esculentum L.) under alternate partial root‐zone irrigation (APRI). Three irrigation modes comprised conventional irrigation (CI) and two kinds of APRI, i.e., APRI with water content in the drying soil compartment controlled at ≥ 60% or 40% of the water‐holding capacity (APRI‐60, APRI‐40). Two N forms included ammonium‐N and nitrate‐N supplied as calcium nitrate or ammonium sulfate, respectively. The results show that APRI‐60 enhanced root growth and increased leaf IWUE with a slight yield reduction compared with CI regardless of the N form supplied. In contrast, APRI‐40 significantly decreased root growth and inhibited photosynthesis, thereby resulting in a significant yield loss. In addition, at the flowering stage tomato plants grew better with ammonium‐N than nitrate‐N supply; however, at the fruit expansion stage and maturity stage, the tomato plants had a higher biomass accumulation and yield with nitrate‐N than ammonium‐N supply. Therefore, the application of APRI should consider the soil water condition coupled with an appropriate N form. In the present study, APRI controlled at ≥ 60% of the water‐holding capacity (WHC) for the drying soil side with nitrate‐N supply was the best water‐fertilizer supply for tomato cultivation. |
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Keywords: | alternate partial root‐zone irrigation / Lycopersicon esculentum L. nitrogen form root growth instantaneous water use efficiency yield |
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