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 are...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.展开更多
Newly planted apple orchards in the USA comprising the highly biennial cultivar, “Honeycrisp”, are prone to flower within the first two years from planting and set fruit. These processes limit canopy development and...Newly planted apple orchards in the USA comprising the highly biennial cultivar, “Honeycrisp”, are prone to flower within the first two years from planting and set fruit. These processes limit canopy development and subsequent yield potential. GA4 + 7 can inhibit floral formation processes of apples. The timing and dose for eliminating return bloom of young “Honeycrisp” trees, however, is unclear. A factorial experimental design to test GA4 + 7 application timing and rate produced significant reductions in return bloom for both factors and their interaction. Treatment responses demonstrated that florigenic processes in “Honeycrisp” occurred early. The most pronounced reduction in return bloom followed the 2-week after full bloom (WAFB) application timing, increasing with increasing rate. The effect on return bloom was progressively diminished over the next two weeks of applications but remained significantly lower than the control. Three successive applications timed one week apart eliminated return bloom of spurs at the highest rate. Both factors and their interaction also significantly reduced return bloom of terminal buds of leaders;in contrast to floral buds on spurs, the response of terminal buds on leaders improved with delayed application timings. Timing exerted a stronger effect than rate on return flowering of the terminal buds of leaders. Leader growth was positively affected by GA4 + 7, the year of application, when three successive applications were made. Tree height, overall growth, expressed as the increase in trunk cross-sectional area, and limb number were also significantly improved by GA4 + 7 but varied in their responses to application timing and rate, and were inconsistent. Overall, successive applications of GA4 + 7 had good efficacy for inhibiting floral initiation of meristems on spurs and terminals while improving the vegetative growth of young “Honeycrisp” trees.展开更多
【目的】以黄土高原半干旱区有限降水持续高效利用为目标,研究不同覆膜方式下连作玉米(Zea May L.)的产量表现和水分利用特征,揭示其增产机理,明确不同覆膜方式下有利于土壤水分持续高效利用的连作年限,为试区高产、水分高效持续利用型...【目的】以黄土高原半干旱区有限降水持续高效利用为目标,研究不同覆膜方式下连作玉米(Zea May L.)的产量表现和水分利用特征,揭示其增产机理,明确不同覆膜方式下有利于土壤水分持续高效利用的连作年限,为试区高产、水分高效持续利用型玉米连作技术提供理论依据。【方法】以田间定位试验为基础,量化连作玉米农田土壤水分的年际平衡关系、产量稳定性;以持续高产和收获期不发生土壤干燥化为依据,确定适用于不同覆膜方式的玉米连作年限。【结果】3年试验结果表明,全膜双垄沟播具有良好的保墒、提高土壤水分有效性,利于协调关键生育时期土壤-作物的水分供需关系,提高产量和水分利用效率的作用。与半膜平作处理相比,全膜双垄沟播玉米的籽粒产量、水分利用效率分别提高了41.8%和33.4%,生物产量、单位耗水的干物质累积量、总产值、净产值、毫米水产值和产投比分别提高了21.8%、12.3%、31.2%、27.8%、21.1%和-3.2%;与露地栽培处理相比生物产量、单位耗水的干物质累积量、总产值、净产值、毫米水产值和产投比分别提高了24.9%、39.1%、225.5%、1 423.9%、212.4%和93.5%。地膜覆盖增大了玉米全生育时期的耗水量,全膜双垄沟播、全膜平作和半膜平作耗水量较露地栽培增幅分别为15.5%—29.2%、10.0%—20.8%和4.2%—12.6%。单季较高的耗水量导致3种覆盖处理在连作第二年收获期土壤贮水量较连作开始期分别降低了37.3%、33.5%和30.9%,第三年降低了29.6%、27.5%和23.9%,造成土壤水分亏缺;随着连作年限的延长,土壤水分亏缺累计,出现土壤干化现象,引起产量波动,不利于土壤水分的持续利用。【结论】黄土高原半干旱区,在同等降雨条件下,全膜双垄沟播具有明显的增产增效和提高水分利用效率的作用,是理想的玉米种植模式;当年降雨量在320 mm左右时,全膜双垄沟播玉米连作不宜超过2年,全膜平作、半膜平作玉米的连作时间不宜超过3年。展开更多
调查分析了五三农场果团三个砂梨品种(Pyrus pyrlfolla Nakai)树体状况与结果的关系。结果显示:砂梨平均单果重量 Y 与果实负载量 X 在一定范围内,呈极显著的负相关,且因品种而异,湘南,晚三吉、长十郎相关方程分别为: _1=247.25-11.28x_...调查分析了五三农场果团三个砂梨品种(Pyrus pyrlfolla Nakai)树体状况与结果的关系。结果显示:砂梨平均单果重量 Y 与果实负载量 X 在一定范围内,呈极显著的负相关,且因品种而异,湘南,晚三吉、长十郎相关方程分别为: _1=247.25-11.28x_1, _2=220.53-8.37x_2, _3=162.65-4.03x_3;结果枝组姿态对单果重量的影响,与品种习性有关,晚三吉梨果个大小随枝组从直立到斜生、平生和下垂的变化过程由大变小,大小差异经邓肯法检验,均达到显著水平;湘南梨果个大小受枝组姿态影响差异不明显。展开更多
基金funded by the National Key Research and Development Program of China (2016YFD0201137 and 2016YFE0101100)the Innovative Group Grant of the National Science Foundation of China (31421092)
文摘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.
文摘Newly planted apple orchards in the USA comprising the highly biennial cultivar, “Honeycrisp”, are prone to flower within the first two years from planting and set fruit. These processes limit canopy development and subsequent yield potential. GA4 + 7 can inhibit floral formation processes of apples. The timing and dose for eliminating return bloom of young “Honeycrisp” trees, however, is unclear. A factorial experimental design to test GA4 + 7 application timing and rate produced significant reductions in return bloom for both factors and their interaction. Treatment responses demonstrated that florigenic processes in “Honeycrisp” occurred early. The most pronounced reduction in return bloom followed the 2-week after full bloom (WAFB) application timing, increasing with increasing rate. The effect on return bloom was progressively diminished over the next two weeks of applications but remained significantly lower than the control. Three successive applications timed one week apart eliminated return bloom of spurs at the highest rate. Both factors and their interaction also significantly reduced return bloom of terminal buds of leaders;in contrast to floral buds on spurs, the response of terminal buds on leaders improved with delayed application timings. Timing exerted a stronger effect than rate on return flowering of the terminal buds of leaders. Leader growth was positively affected by GA4 + 7, the year of application, when three successive applications were made. Tree height, overall growth, expressed as the increase in trunk cross-sectional area, and limb number were also significantly improved by GA4 + 7 but varied in their responses to application timing and rate, and were inconsistent. Overall, successive applications of GA4 + 7 had good efficacy for inhibiting floral initiation of meristems on spurs and terminals while improving the vegetative growth of young “Honeycrisp” trees.
文摘【目的】以黄土高原半干旱区有限降水持续高效利用为目标,研究不同覆膜方式下连作玉米(Zea May L.)的产量表现和水分利用特征,揭示其增产机理,明确不同覆膜方式下有利于土壤水分持续高效利用的连作年限,为试区高产、水分高效持续利用型玉米连作技术提供理论依据。【方法】以田间定位试验为基础,量化连作玉米农田土壤水分的年际平衡关系、产量稳定性;以持续高产和收获期不发生土壤干燥化为依据,确定适用于不同覆膜方式的玉米连作年限。【结果】3年试验结果表明,全膜双垄沟播具有良好的保墒、提高土壤水分有效性,利于协调关键生育时期土壤-作物的水分供需关系,提高产量和水分利用效率的作用。与半膜平作处理相比,全膜双垄沟播玉米的籽粒产量、水分利用效率分别提高了41.8%和33.4%,生物产量、单位耗水的干物质累积量、总产值、净产值、毫米水产值和产投比分别提高了21.8%、12.3%、31.2%、27.8%、21.1%和-3.2%;与露地栽培处理相比生物产量、单位耗水的干物质累积量、总产值、净产值、毫米水产值和产投比分别提高了24.9%、39.1%、225.5%、1 423.9%、212.4%和93.5%。地膜覆盖增大了玉米全生育时期的耗水量,全膜双垄沟播、全膜平作和半膜平作耗水量较露地栽培增幅分别为15.5%—29.2%、10.0%—20.8%和4.2%—12.6%。单季较高的耗水量导致3种覆盖处理在连作第二年收获期土壤贮水量较连作开始期分别降低了37.3%、33.5%和30.9%,第三年降低了29.6%、27.5%和23.9%,造成土壤水分亏缺;随着连作年限的延长,土壤水分亏缺累计,出现土壤干化现象,引起产量波动,不利于土壤水分的持续利用。【结论】黄土高原半干旱区,在同等降雨条件下,全膜双垄沟播具有明显的增产增效和提高水分利用效率的作用,是理想的玉米种植模式;当年降雨量在320 mm左右时,全膜双垄沟播玉米连作不宜超过2年,全膜平作、半膜平作玉米的连作时间不宜超过3年。
文摘调查分析了五三农场果团三个砂梨品种(Pyrus pyrlfolla Nakai)树体状况与结果的关系。结果显示:砂梨平均单果重量 Y 与果实负载量 X 在一定范围内,呈极显著的负相关,且因品种而异,湘南,晚三吉、长十郎相关方程分别为: _1=247.25-11.28x_1, _2=220.53-8.37x_2, _3=162.65-4.03x_3;结果枝组姿态对单果重量的影响,与品种习性有关,晚三吉梨果个大小随枝组从直立到斜生、平生和下垂的变化过程由大变小,大小差异经邓肯法检验,均达到显著水平;湘南梨果个大小受枝组姿态影响差异不明显。
