Compaction layers are widely distributed in the Huang-Huai-Hai Plain, China, which restrict root growth and reduce yields.  The adoption of subsoiling has been recommended to disrupt compacted soil layers and create a reasonable soil structure for crop development.  In this paper, the effects of subsoiling depth (30, 35 and 40 cm), period interval (2 or 3 years) and combined pre-sowing tillage practice (rotary cultivation or ploughing) on soil condition improvement was studied on a tidal soil in the Huang-Huai-Hai Plain.  Seven tillage patterns were designed by combining different subsoiling depths, period intervals and pre-sowing.  The evaluation indicators for soil condition improvement were as follows: thickness of the plough layer and hard pan, soil bulk density, cone index, soil three-phase R values, alkali nitrogen content, crop yield, and economic benefits.  The results showed that subsoiling can significantly improve the soil structure and physical properties.  In all subsoiling treatments, the depth of 35 or 40 cm at a 2-year interval was the most significant.  The thickness of the plough layer increased from 13.67 cm before the test to 21.54–23.45 cm in 2018.  The thickness of the hard pan decreased from 17.68 cm before the test to 12.09–12.76 cm in 2018, a decrease of about 40.07%.  However, the subsoiling combined pre-sowing tillage practice, that is, rotary cultivation or ploughing, was not significant for soil structure and physical properties.  For all subsoiling treatments, the soil bulk density, cone index and soil three-phase R values of the 15–25 cm soil layer were significantly lower compared to single rotary cultivation.  Subsoiling was observed to increase the soil alkaline nitrogen and water contents.  The tillage patterns that had subsoiling at the depth of 35–40 cm at a 2-year interval combined with rotary cultivation had the highest alkali nitrogen and water contents, which increased by 31.08–34.23% compared with that of the single rotary cultivation.  Subsoiling can significantly increase the yield both of wheat and corn, as well as the economic benefits.  The treatment of subsoiling at the depth of 35 cm at an interval of 2 years combined with rotary cultivation had the highest annual yield and economic benefits.  For this treatment, the annual yield and economic benefits increased by 14.55 and 62.87% in 2018, respectively.  In conclusion, the tillage patterns that involved subsoiling at a depth of 35 cm at a 2-year interval along with rotary cultivation are suitable for the Huang-Huai-Hai Plain.

 

Mango is an important cash crop in the tropics and subtropics.  Determining the yield gap of mango and production constraints can potentially promote the sustainable development of the mango industry.  In this study, boundary line analysis based on survey data from 103 smallholder farmers and a yield gap model were used to determine the yield gap and production constraints in mango plantations in the northern mountain, central valley and southern mountains regions of Tianyang County, Guangxi, China.  The results indicated that the yield of mango in three representing regions of Tianyang County, Northern Mountains, Central Valley and Southern Mountains, was 18.3, 17.0 and 15.4 t ha^–1 yr^–1, with an explainable yield gap of 10.9, 6.1 and 14.8 t ha^–1 yr^–1, respectively.  Fertilization management, including fertilizer N, P₂O₅ and K₂O application rates, and planting density were the main limiting factors of mango yield in all three regions.  In addition, tree age influenced mango yield in the Northern Mountains (11.1%) and Central Valley (11.7%) regions.  Irrigation time influenced mango yield in the Northern Mountains (9.9%) and Southern Mountains (12.2%).  Based on a scenario analysis, the predicted yield would increase by up to 50%, and fertilizer N use would be reduced by as much as approximately 20%.  An improved understanding of production constraints will aid in the development of management strategy measures to increase mango yield.

Apple occupies a dominant position in fruit production globally, and has become the main income source of local smallholder farmers in Luochuan County in the Loess Plateau area, one of the largest apple production areas in China.  However, the annual productivity of apple orchards in this region remains low and has gradually declined over the years.  The distinction and correlation of production constraints can contribute to the promotion of apple orchard productivity and the development of a sustainable orchard system.  In the present study, survey data from 71 smallholder farmers were analyzed using a yield gap model to distinguish the production constraints and determine their correlation with the yield gap based on the structural equation model (SEM).  The results indicated that the average apple yield in Luochuan County was 29.9 t ha^–1 yr^–1, while the attainable yield (Yatt; the highest yield obtained from the on-farm surveys) was 58.1 t ha^–1 yr^–1.  The average explained and unexplainable yield gaps were 26.3 and 1.87 t ha^–1 yr^–1.  According to the boundary line analysis, crop load, number of sprayings and base fertilizer N were the top three constraints on apple production in 9.8, 7.8 and 7.8% of the plots, respectively.  Among the production constraints, crop load and fruit weight affected apple yield through direct pathways, whereas other constraints influenced apple yield through an indirect pathway based on the SEM, explaining 51% of the yield variance by all the main production constraints.  These results can improve the current understanding of production constraints and contribute to the development of management strategies and policies for improving apple yield.

Zinc finger-homeodomain proteins (ZF-HDs) are transcription factors that regulate plant growth, development, and abiotic stress tolerance.  The SL-ZH13 gene was found to be significantly upregulated under drought stress treatment in tomato (Solanum lycopersicum) leaves in our previous study.  In this study, to further understand the role that the SL-ZH13 gene plays in the response of tomato plants to drought stress, the virus-induced gene silencing (VIGS) method was applied to downregulate SL-ZH13 expression in tomato plants, and these plants were treated with drought stress to analyze the changes in drought tolerance.  The SL-ZH13 silencing efficiency was confirmed by quantitative real-time PCR (qRT-PCR) analysis.  In SL-ZH13-silenced plants, the stems wilted faster, leaf shrinkage was more severe than in control plants under the same drought stress treatment conditions, anyd the mean stem bending angle of SL-ZH13-silenced plants was smaller than that of control plants.  Physiological analyses showed that the activity of superoxide dismutase (SOD) and peroxidase (POD) and the content of proline (Pro) in SL-ZH13-silenced plants were lower than those in control plants after 1.5 and 3 h of drought stress treatment.  The malondialdehyde (MDA) content in SL-ZH13-silenced plants was higher than that in control plants after 1.5 and 3 h of drought stress treatment, and H₂O₂ and O₂^-· accumulated much more in the leaves of SL-ZH13-silenced plants than in the leaves of control plants.  These results suggested that silencing the SL-ZH13 gene affected the response of tomato plants to drought stress and decreased the drought tolerance of tomato plants. 

The Oriental fruit fly, Bactrocera dorsalis (Hendel), is among the most destructive fruit/vegetable-eating agricultural pests in the world, particularly in Asian countries such as China.  Because of its widespread distribution, invasive ability, pest status, and economic losses to fruit and vegetable crops, this insect species is viewed as an organism warranting severe quarantine restrictions by many countries in the world.  To understand the characteristics and potential for expansion of this pest, this article assembled current knowledge on the occurrence and comprehensive control of the Oriental fruit fly in China concerning the following key aspects: invasion and expansion process, biological and ecological characteristics, dynamic monitoring, chemical ecology, function of symbionts, mechanism of insecticide resistance, control index, and comprehensive control and countermeasures.  Some suggestions for the further control and study of this pest are also proposed.