An Optimum Irrigation Schedule with Aeration for Greenhouse Tomato Cultivations Based on Entropy Evaluation Method

Abstract

To balance multiple objectives of high yield by farmers, high quality by customers, and high irrigation water use efficiency (IWUE) for sustainable development of agriculture, a two-growing-season study was performed to test the effect of aeration at three irrigation levels (60%, 80%, and 100% of full irrigation) on crop growth, nutrient uptake, yield, IWUE, and fruit quality of tomato. The results showed that compared to the control, aeration significantly increased total dry weight at harvest, total N and K accumulation, which increased tomato yield by 23% and IWUE by 23% (p < 0.05). Yield and IWUE were significantly affected by irrigation with the increasing rate of 20.5% and 14.3% for yield, and with the decreasing rate of 27.7% and 8.6% for IWUE under 100% of full irrigation than that under 60% and 80% of full irrigation, respectively. Aeration positively impacted fruit quality while irrigation had a negative impact (p > 0.05). Based on these indicators, full irrigation with aeration could be an appropriate schedule for greenhouse tomato cultivations by the entropy evaluation method with the comprehensive score of 0.879 and 0.77 for the spring-summer and autumn-winter season, respectively. The result is of great significance to the farmers’ or researchers’ management of aerated irrigation in greenhouse tomatoes.

Irrigation Combined with Aeration Promoted Soil Respiration through Increasing Soil Microbes, Enzymes, and Crop Growth in Tomato Fields

“…Taking dry biomass at harvest (142 DAT) as an example, dry biomass of tomato leaf, stem, fruit, and root under aeration were higher than the control ( Figure 5). As reported previously [31], the average increases of each part were 17.8%, 17.7%, 17.8%, and 8.4%, respectively, and the effect of aeration on leaf, stem, and fruit was significant ( Table 2, p < 0.05). These improvements of dry biomass were in agreement with the results of former research [4,32], which were beneficial from increased soil aeration and reduced phytohormones under AI [31].…”

“…As reported previously [31], the average increases of each part were 17.8%, 17.7%, 17.8%, and 8.4%, respectively, and the effect of aeration on leaf, stem, and fruit was significant ( Table 2, p < 0.05). These improvements of dry biomass were in agreement with the results of former research [4,32], which were beneficial from increased soil aeration and reduced phytohormones under AI [31]. Dry biomass of tomato leaf, stem, fruit, and root increased as irrigation amount increased, and the effect was significant on leaf, fruit, and root In our study, the highest mean values of soil microbe and enzyme activity were obtained when 100%W was applied coupled with AI.…”

“…Dry biomass of tomato leaf, stem, fruit, and root increased as irrigation amount increased, and the effect was significant on leaf, fruit, and root ( Table 2, p < 0.05). As noted previously [31], dry weight of root, stem, leaf, and fruit under 100%W was increased by 22.2%, 19.3%, 22.5%, and 19.0%, and by 20.1%, 5.4%, 7.0%, and 12.1% than that under 60%W and 80%W treatment, respectively. Zhu et al [4] demonstrated that with crop-pan coefficient increasing from 0.6 to 1.0, dry biomass of root, stem, and leaf was increased by 24.0%, 17.2%, and 22.8%, respectively.…”

“…Daily maximum and minimum temperatures inside the greenhouse during the experimental period, collected by an Automatic Meteorological Observing Station (Hobo event logger, Onset Computer Corporation, Bourne, MA, USA), are shown in Figure 8. The weather station, which was placed 2 m above the ground, recorded meteorological data at an interval of 15 min [31]. Higher temperatures were observed in August, while lower temperatures were recorded in December (Figure 8).…”

“…Therefore, six treatments were designed (W 0.6 O, W 0.6 S, W 0.8 O, W 0.8 S, W 1.0 O, and W 1.0 S). Three replicates of each treatment were used (18 total plots), and the experiment was arranged using a randomized block [31]. Each plot with one row was 4 × 0.8 m in size, with eleven tomato plants of cultivar "JINGPENG SEED" planted on 6 August 2017.…”