Mingzhi Zhang

Introduction: There is a limited amount of research available on how changes in soil hydrothermal cycles impact soil N₂O emissions in greenhouses that use a tomato irrigation system with micro-sprinkler irrigation mulched (MSM).Methods: This study examined the effects of different irrigation frequency (F, F1 which is every 3 days, F2 which is every 5 days, F3 which is every 7 days) and irrigation amount (I, I1 which is 0.7 Epan, I2 which is 1.0 Epan, I3 which is 1.2 Epan) on soil N₂O emissions in tomato cultivation. The research was carried out using a randomized experimental design over two consecutive growing seasons for greenhouse tomatoes in Northwest China.Results: The findings revealed that F1 and F3 did not support the accumulation of microbial biomass carbon and nitrogen in the tomato soil under MSM. This limitation hindered the enhancement of soil extracellular enzymes BG and LAP, and decreased the diversity of the bacterial community structure. The functional genes related to bacterial nitrogen metabolism were abundant. The application of I2 treatment can result in a high accumulation of microbial biomass carbon and nitrogen in tomato soil, leading to enhanced soil BG and LAP activities and contributing to the stability of the soil bacterial community structure. As the F decreased, the cumulative emission flux of N₂O in tomato soil initially decreased, then increased. Increasing the I showed a rising trend in the cumulative emission flux of N₂O in tomato soil. The yield of spring and autumn tomatoes in F2 was higher compared to F1 and F3 at approximately 5.27 and 3.24%, and 19.31 and 11.30%, respectively. The yield of spring and autumn tomatoes in I2 was around 24.44 and 26.15% higher than in I1 and 1.64 and 3.06% higher than in I3. The regulation of the irrigation system in MSM resulted in a favorable interaction among tomato soil, microbial biomass carbon and nitrogen, soil extracellular enzymes, and soil bacterial community. When the I increased by 1.00%, the cumulative N₂O emission flux and yield of tomato soil increased by at least 30.68 and 39.24%, respectively. For every 1.00% increase in F, the cumulative N₂O emission flux and yield of tomato soil decreased by at least 7.41% and 11.23%, respectively. A quadratic relationship was observed between soil N₂O emission flux and the abundance and yield of soil bacterial nitrogen metabolism functional genes. The assessment of tomato yield potential in the area could be indirectly done by examining the abundance of soil bacterial nitrogen metabolism functional genes. The study demonstrates the feasibility of regulating soil N₂O emissions under the MSM irrigation system. Moreover, the findings indicate that F2I2 can significantly improve tomato yield without causing a considerable rise in soil N₂O emission flux.Discussion: This conclusion can provide a scientific basis for the optimization of irrigation system in facility agriculture, so as to ensure the high yield of crops and reduce the negative impact on the environment. It is also of great significance for the green development of agriculture under the background of global climate change.

Moistube irrigation was driven by the gradient of water potential inside and outside the pipe wall, which has the advantages of continuous irrigation during the crop growth period. However, the response mechanism of soil nutrients and enzyme activities of greenhouse tomatoes under the integration of water and fertilizer by moistube irrigation is still unclear. In order to explore the changes in soil nutrients and enzyme activities of greenhouse tomatoes regulated by irrigation and fertilization in moistube irrigation greenhouse, a completely randomized experimental design was conducted to explore the effects of different irrigation amounts (I, controlling the working pressure head of moistube to achieve different irrigation amount gradients, capillary working pressure was 1 (I1), 2 (I2), 3 (I3) m) and fertilization amounts (F, single fertilization amount was 100 (F1), 200 (F2), 300 (F3) kg/hm2) on soil nutrients, enzyme activities and yield of greenhouse tomato. It was found that with the increase of I, the total organic carbon content (TOC), soil β-glucosidase (BG), leucine amino peptidase (LAP), N-acetylglucosaminidase (NAG), and alkaline phosphatase (AP) activities enzyme of greenhouse tomato soil increased first and then decreased. When the I increased from I1 to I3, the soil total nitrogen (TN) decreased by 5.07% and 4.91%, respectively, and the soil total phosphorus (TP) by 4.37% and 4.22%, respectively. With the increase of fertilizer amounts, the TOC of tomato soil increased first and then decreased, the activities of BG, LAP, NAG and AP in soil increased first and then decreased, and the contents of TN and TP in soil decreased by 4.79% and 4.68%, 12.32% and 10.47%, respectively. The yield of tomatoes treated with I2 was significantly higher than that of I1 and I3 by about 13.99% and 1.29%, respectively. The tomato yield of F2 treatment was significantly higher than that of F1 and F3 treatments by about 22.57% and 1.72%, respectively. Based on the analysis of stoichiometry, it was found that soil carbon was more scarcity than nitrogen in greenhouse tomatoes under the integration of water and fertilizer by moistube irrigation. Soil carbon, nitrogen, phosphorus, enzyme activity and their respective stoichiometry showed a quadratic curve relationship with yield. Therefore, I2F2 treatment of greenhouse tomatoes can not only reduce soil carbon and nitrogen limitations but also improve soil enzyme activity and achieve multiple goals of increasing greenhouse tomato yield, and saving water and fertilizer. This conclusion contributes to a more reasonable irrigation and fertilization of tomatoes in moistube irrigation greenhouse and soil nutrient management of facility agriculture through empirical proofs.

The micro-sprinkler irrigation mulched (MSM) has been suggested as a novel water-saving approach in controlled environment agriculture. However, the effects of microbial community structure and enzyme activity in the rhizosphere soil on crop growth under MSM remain unclear. This study conducted a randomized experimental design using greenhouse tomatoes to investigate changes in bacterial community structure and enzyme activity in rhizosphere soil under different irrigation frequencies (F) and amounts (I) of MSM. The findings revealed that with the increase of F or I, The total count of soil bacteria in tomatoes first rose and then fell in terms of Operational Taxonomic Units (OTUs) classification. Compared to other F, the most abundance of nitrogen and phosphorus metabolism genes and enzyme activities were observed with a 5-day F. Moreover, the diversity of soil bacterial community structure initially rose before eventually declining with the increase of the I. Applying 1.00 Epan (cumulative evaporation of a 20 cm standard pan) under MSM helped boost the abundance of nitrogen and phosphorus metabolism functional genes in soil bacteria, ensuring higher enzyme activities related to nitrogen, carbon, and phosphorus metabolism in the rhizosphere soil of tomatoes. Tomatoes’ yield initially rose before eventually declining with the increase in F or I, whereas I had a more significant effect on yield. A 1.00% increase in I yielded a minimum of 39.24% increase in tomato yield. The study showed a positive correlation between soil bacterial community, soil enzyme activity, and greenhouse tomato yield under MSM. Considering the results comprehensively, the combined irrigation mode of F of 5 d and I of 1.00 Epan was recommended for greenhouse tomatoes under MSM. This conclusion provides theoretical support for water-saving practices and yield improvement in facility agriculture, especially tomato cultivation.

To determine suitable thresholds for deficit irrigation of winter wheat in the well-irrigated area of the Huang-Huai-Hai Plain, we investigated the effects of different deficit irrigation lower limits and quotas on the photosynthetic characteristics and grain yield of winter wheat. Four irrigation lower limits were set for initiating irrigation (i.e., light drought (LD, 50%, 55%, 60% and 50% of field holding capacity (FC) at the seedling-regreening, jointing, heading and filling-ripening stages, respectively), medium drought (MD, 40%, 50%, 55% and 45% of FC at the same stages, respectively), adequate moisture (CK1, 60%, 65%, 70% and 60% of FC at the same stages, respectively), heavy drought (CK2, 35%, 40%, 45% and 40% of FC at the same stages, respectively)) and five irrigation quota per event (30, 60, 90, 120 and 180 mm) were set for each lower limit. We found that the increase of drought stress is conducive to normal photosynthesis of winter wheat leaves which is supported by the following findings. First, photosynthetic rate (Pn) of LD60 treatment was higher than that of LD30, LD90, LD120, LD180, MD30, MD60, MD90, MD120 and MD180. Then, Under the 90 mm irrigation quota treatment, the yield of winter wheat basically increased with the increase of irrigation’s lower limit. Moreover, With the increase in irrigation quota, the yield of winter wheat increased, and the water use efficiency (WUE) of winter wheat increased at first and then decreased. In addition, compared with the LD30, MD30, MD60, MD90, MD120, and MD180, the yield of winter wheat in LD60 treatment increased by about 3.23% (3-year average), 32.3%, 19.9%, 11.7%, 10.1%, and 14.6%. At the same time, the WUE with LD60 treatment of winter wheat was significantly higher than LD90, LD120, LD180, MD30, MD60, MD90, MD120, MD180 treatments. There was a positive correlation between soil volumetric water content and Pn and between yield and Pn. The key period for yield formation in winter wheat is 180 days after sowing. In conclusion, to achieve the dual goals of stable winter wheat yield and efficient utilization of water resources in this region, the suitable threshold for initiating deficit irrigation of winter wheat is the LD60 treatment. This conclusion provides data support for water-saving and stable yield of winter wheat in this area.

Rhizosphere hypoxia constrains plant growth, and numerous studies have shown that root zone aeration accelerates plant photosynthesis and growth and increases crop yields. Nevertheless, the mechanism by which soil microorganisms are involved in this process is not clear. The purpose of the present study was to examine the effects of aeration and irrigation depth on the composition and structure of rhizosphere soil fungal communities and tomato plant performance. The amount of aeration assayed was equal to 0 (CK), 0.5 (V1), 1 (V2), and 1.5 (V3) times the porosity of the soil. The two depths of subsurface drip irrigation used were 15 (D15) and 40 cm (D40). The results demonstrated that soil aeration not only increased tomato plant performance but also influenced fungal diversity and composition. Compared to the no-aeration treatment, the V3 soil aeration treatment increased the total dry weight and fruit yield by 39.9% and 65.6%, respectively. The results also showed that the abundance of the phylum Ascomycota and the family Lasiosphaeriaceae increased with increasing soil aeration, whereas those of members of the phylum Zygomycota and the order Capnodiales decreased with increasing soil aeration. Moreover, the variation in subsurface irrigation depth altered the rhizosphere soil fungal community. In general, the results of this study demonstrate that root zone aeration can ameliorate hypoxic conditions in Lou soils and is beneficial to soil fungal communities and tomato plant performance. Keywords: tomato, soil aeration, rhizosphere soil fungal community, plant performance DOI: 10.25165/j.ijabe.20231601.6368 Citation: Li Y, Zhang M Z, Cao X S, Wang J W, Zhang Z X, Niu Q W. Subsurface aeration alters the fungal composition of rhizosphere soil and tomato plant performance in Northwest China. Int J Agric & Biol Eng, 2023; 16(1): 172–183.

The mechanism of greenhouse tomato growth and yield under the integrated water and fertilizer of moistube irrigation (MI) is not clear. Thus, to fill the research gap, a completely randomized trial design was used to study the effects of different irrigation amounts (I; to realize different I, the tube working pressure was 1 (I1), 2 (I2), 3 (I3) m) and fertilizer amounts (F, N-P-K: 20%-20%-20%; the F at a single time was 100 (F1), 200 (F2) and 300 (F3) kg/ha) on growth and yield of tomato. The results showed that with an increase in I, the photosynthetic rate (Pn) of leaves and total dry matter mass (TDM) first increased and then decreased, while the nutrition and the flavor indexes of fruit decreased. With an increase in F, the Pn of leaves, the TDM of tomato and the fruit quality increased at first and then decreased. The effects of I on the yield of tomato was higher than that of F. With an increase in I, the partial fertilizer productivity (PFP) increased at first and then decreased, and the water use efficiency (WUE) decreased by 13.96%. With an increase in F, the WUE increased at first and then decreased, and the PFP decreased by 148.97%. The conclusion based on a spatial analysis was consistent with the comprehensive evaluation of yield and water use efficiency, which showed that I2F2 was the best.

The purpose of this study was to analyse the suitability of the frequency and amount of microsprinkler irrigation under plastic film technology (MSPF) in a greenhouse. This study was aimed at determining the effects of different irrigation frequency and irrigation amount of the MSPF on the quality, yield (Y), and water use efficiency (WUE) of tomato, and the optimal irrigation period and irrigation amount of tomato with MSPF were determined by spatial analysis method. Irrigation frequency was set 3 levels, 3 d (F1), 5 d (F3), and 7 d (F3), respectively. Irrigation amount was set 3 levels, 0.7 (I1), 1.0 (I2), and 1.2 (I3) ( is the diameter of 20 cm standard pan evaporation, mm), respectively. The results show that increase in the single fruit weight (SFW), transverse diameter (TD), vertical diameter (VD), total soluble solids (TSS), total soluble sugar (TSU), soluble solid content (SSC), sugar-acid ratio (SAR), soluble protein (SP), vitamin C (VC), lycopene (L), Y, and WUE of spring and autumn tomatoes was observed initially with decreasing irrigation frequency; however, decrease in all these variables was observed thereafter. Similarly, SFW, TD, VD, and SAR of spring and autumn tomatoes first added and then reduced with increasing irrigation amount, whereas TSS, SP, TSU, VC, L, and WUE exhibited an overall decreasing trend. On the basis of spatial analysis, the comprehensive score, Y, and WUE of F2I2 tomato were predicted to simultaneously reach more than 95% of the maximum, which is consistent with the earlier studies on comprehensive evaluation of yield and WUE.

This study aimed to expound the changes in soil water flow, heat transport, and tomato production under micro-sprinkler irrigation and plastic film (MSPF) conditions. The effects of different irrigation amounts (I1:0.7 Epan; I2:1.0 Epan; and I3:1.2 Epan (Epan is the cumulative evaporation from a 20 cm diameter standard pan, mm)) on soil water, soil temperature, and tomato yield were studied. A completely randomized trial design was used; meanwhile, the drip irrigation under plastic film (CK1) and micro-sprinkler irrigation without mulch film (CK2) were used as controls. The results showed that the shape of soil moisture was banded under MSPF; the soil wetting range was larger than that of CK1 and CK2 in the profile of MSPF. The change range of 5 cm soil temperature of MSPF 1–5 days after irrigation was 4.05 °C. The change range of 5 cm soil temperature of MSPF was lower than that of CK1 from 1 to 5 days after irrigation. During the growth period of spring and autumn tomato, the average soil moisture content of 0–40 cm with CK1 was 1.97% and 3.83% (spring and autumn, respectively) higher than that of MSPF, and the average soil temperature of 5–25 cm was 2.36% and 1.66% (spring and autumn, respectively) lower than that of MSPF. Compared with CK2, the average soil moisture content of 0–40 cm under MSPF increased by 8.30% and 3.83% (spring and autumn, respectively), and the average soil temperature of 5–25 cm under MSPF increased by 5.85% and 1.68% (spring and autumn, respectively). The spring and autumn tomato yield of MSPF was significantly higher than that of CK1 by 19.39% and 4.54%, respectively. The spring and autumn tomato yield of MSPF were higher than that of CK2 by about 20.46% and 49.22%, respectively. With an increase in the irrigation amount of MSPF, the soil moisture and yield of spring and autumn tomato increase; the soil temperature and water use efficiency of spring and autumn tomato decrease. Considered comprehensively, the MSPF can be used as one of the methods of greenhouse tomato micro-irrigation, and 1.0 Epan is recommended for irrigation parameters in northwest China facility agriculture.

Agriculture is a major source of global greenhouse gas emissions. Approximately 1/3 of vegetables in China are produced in greenhouses. However, the effects of different irrigation strategies and plastic film (PF) mulching combinations on N₂O emissions and tomato fruit yields in greenhouses are unclear. The aims of this study were to explore the effects of micro-sprinkler irrigation under plastic film (MSPF), drip irrigation under plastic film (DIPF) and micro-sprinkler irrigation (MSI) on the soil nutrients, enzyme activity, nirS-type denitrifying bacterial community, N₂O emissions and fruit yields of tomato. The results showed that MSPF could improve the uniformity of soil water distribution and surface (0–40 cm) soil water content. Film mulching could increase soil temperature at depths of 5–25 cm. Both MSPF and DIPF increased microbial nitrogen, promoted the activity of rhizosphere soil urease and leucine aminopeptidase, changed the community of denitrifying bacteria, accelerated the turnover of soil nutrients and improved yield and water use efficiency. PF mulching had a greater impact on the nirS-type denitrifying bacterial community when compared to irrigation strategy. We conclude that MSPF can be used to configure commercially available installation and operation. The comprehensive benefit of MSPF treatment is that it is more profitable than that of DIPF.