增氧地下滴灌改善土壤通气性促进番茄生长

    Aerated subsurface drip irrigation improving soil aeration and tomato growth

    • 摘要: 增氧地下滴灌将空气与灌溉水混匀后输送到作物根区,可实现作物提质增产和水肥高效利用,而其关键作用机制尚不明确。该文以番茄为供试作物,设置灌水量和增氧量2因素2水平完全随机区组试验,记为W1和W2(分别为作物-蒸发皿系数的0.6和1.0倍)、A和C(增氧和对照组),系统监测了壤质黏土条件下作物生长生理动态与土壤通气性状况,探究土壤通气性与作物生长之间的响应机制。结果表明,增氧地下滴灌对土壤溶解氧浓度、氧气扩散速率、氧化还原电位和土壤呼吸有一定的改善作用。与对照相比,W2A处理开花坐果期灌水后第2天的土壤溶解氧浓度、氧气扩散速率、氧化还原电位和土壤呼吸速率提高了25.71%、52.90%、41.99%和64.70%(P<0.05)。土壤氧气扩散速率和氧化还原电位分别与溶解氧浓度和充气孔隙度呈极显著正相关(P<0.01)。增氧地下滴灌促进了番茄生物量积累和养分利用,促进了作物的光合作用,表现为产量提高和品质改善。与对照相比,W2A处理3个时期的光合速率分别增大14.51%、21.72%和13.76%(P<0.05),地上及地下部鲜质量分别增加了68.14%和55.18%(P<0.05),根、茎、叶氮素吸收量增加了52.94%、42.03%和24.12%(P<0.05),产量、可溶性固形物和维生素C含量增加了66.40%、51.77%和20.26%(P<0.05)。1.0倍作物-蒸发皿系数灌水时增氧处理在改善土壤通气性,促进番茄生长,提高番茄产量方面的效果最为明显。作物产量与溶解氧浓度、氧化还原电位及土壤呼吸均值均呈显著正相关(P<0.05),作物品质(可溶性固形物、总酸含量)与土壤溶解氧浓度、氧气扩散速率和土壤呼吸均值呈显著正相关(P<0.05)。研究结果为揭示增氧地下滴灌对土壤通气性的改善效应提供了科学依据。

       

      Abstract: Abstract: Effects of aerated subsurface drip irrigation (ASDI) on yield potential and quality of crop, and relationships between soil aeration, crop yield and fruit quality are less known so far. In order to reveal the relationship between crop growth and soil aeration under ASDI, a pot experiment was conducted using tomato in the Efficiency Agriculture Water Experimental Farm of North China University of Water Resources and Electric Power (34°47′5.91″N, 113°47′20.15″E). Herein, 2 levels of irrigation amount (W1 and W2 as 0.6 and 1.0 times of the crop-pan coefficient, respectively) and 2 aeration treatments (A and C as ASDI and control treatment, i.e., non-aeration treatment by subsurface drip irrigation) were set up. During the trial, the soil aeration index under a loamy clay soil, such as air-filled porosity, soil dissolved oxygen (DO), oxidation-reduction potential (Eh), oxygen diffusion rate (ODR), soil respiration, photosynthesis index, crop aboveground biomass, root biomass, nutrient uptake, yield and fruit quality were monitored systematically. The correlation analysis was conducted among soil aeration index, photosynthesis index, nutrient uptake efficiency, yield, and fruit quality. Results showed that the ASDI improved the soil aeration. Compared to control treatment groups, the DO in W2A and W1A treatments were increased by 25.71% and 10.64% on the next day after irrigation at flowering and fruit bearing period (P<0.05). In W2A and W1A, similarly, the ODR were increased by 52.90% and 32.27% and the Eh were increased by 41.99% and 20.99%, respectively (P<0.05). In contrast with the control groups, the soil respiration in W2A and W1A were significantly increased by 64.70% and 28.45% during the flowering and fruit bearing period, 14.17% and 33.24% during the fruit expanding period, 56.91% and 32.86% during the mature period (P<0.05). Meanwhile, there were obvious positive correlations between ODR and Eh and DO and air-filled porosity (P<0.01). The ASDI had a positive effect on the crop photosynthesis, benefiting the increment in biomass, nutrient uptake and crop quality. Compared to the control groups, the net photosynthetic rate in W2A treatment at flowering and fruit bearing period, fruit expanding period and mature period were increased by 14.51%, 21.72% and 13.76%, respectively (P<0.05). The net photosynthetic rate in W1A treatment at fruit expanding period was increased by 55.26% (P<0.05). The aboveground fresh weight and root fresh weight significantly increased by 68.14% and 55.18% in W2A treatment, while the aboveground fresh weight and root fresh weight increased by 9.88% and 45.37% in W1A treatment (P<0.05). Compared to the control treatment, nitrogen uptake in root, stem and leaf were increased by 52.94%, 42.03% and 24.12%, and phosphorus utilization in root and stem were increased by 74.07% and 36.00%, while the potassium accumulation in root, stem and leaf were increased by 56.52%, 41.09% and 22.44% in W2A treatment (P<0.05). Similarly, the crop yield, fruit soluble solids, vitamin C content, total acid content and soluble protein in W2A were increased by 66.40%, 51.77%, 20.26%, 55.26% and 63.64%, respectively (P<0.05). The fruit soluble solids, vitamin C content and total acid content in W1A treatment were increased by 43.55%, 29.68% and 71.43%, respectively (P<0.05). The ASDI treatment at the irrigation of 1.0 times of the crop-pan coefficient showed the most efficient promotion on soil aeration, crop growth and fruit quality enhancement. There were significantly positive correlations between crop yield and DO, Eh and respiration under ASDI (P<0.05). In addition, there were positive correlations between crop quality (soluble solids and total acid content) and soil aeration indexes (DO, ODR and respiration) (P<0.05). In sum, these results would provide valuable information for the effect of ASDI on soil aeration, crop yield and fruit quality enhancement.

       

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