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Sanborn试验地建立于1888年,是密西西比河西部建立最早的一个农业试验地.它为长期作物轮作和土壤管理,包括每年的施肥对土壤侵蚀以及这些技术措施的持续性的影响提供了可靠的依据.对各试验小区中连作玉米的、连作梯牧草的和6年一轮玉米、燕麦、小麦、三叶草及2年梯牧草轮作的连续耕作100年后的表土保留情况进行了分析.结果表明,种植100年后的连作玉米小区比6年一轮梯牧草小区保留的表土有明显减少.连作玉米小区保留的表土只相当于梯牧草小区的44%.而轮作小区则相当于梯牧草小区的70%.连作玉米小区耕层的粘土含量比轮作和梯牧草小区有显著增高,而且玉米小区还出现耕层与底层粘土混合的现象.据测产表明,在有侵蚀的小区即使施用大量肥料,其玉米产量仍比无侵蚀小区减产60%.因此,如果要持续长期生产就必须改进条播耕作管理工作.
Established as the earliest experimental farm in western Mississippi, the Sanborn trial was established in 1888. It provides a reliable basis for long-term crop rotation and soil management, including the effects of annual fertilization on soil erosion and the persistence of these technological measures The topsoil retention after 100 years of continuous tillage with continuous maize and even six-year-old corn, oats, wheat, clover and two-year-old grasses in each experimental plot was analyzed.The results showed that planting After 100 years of continuous cropping corn plot than 6 years of a step ladder grassland retained topsoil significantly reduced.Copper corn retained area of the topsoil is only equivalent to 44% of timothy grassland.While the rotation of the community is equivalent to the tim grass community 70% The clay content of the tillage layer in the continuous cropping corn plot was significantly higher than that of the crop rotation and the timothy grass plot, and the tillage layer was also mixed with the bottom tillage clay in the maize plot.According to the survey results, even in the eroded plot, Production is still 60% less than non-eroded plots, so managing tillable tillage must be improved if long-term production is to continue.