土壤管理.ppt

What is Tillage? The practice of keeping the soil mellow (soft) and free from weeds mechanically (physically) Can be seedbed preparation or post-emergence cultivation What are the purposes of tillage?土壤耕作的目的 调节耕层三相比，创造深厚的耕层和适宜的苗床 To adjust the water-air-solid proportion in topsoil；Creating deep tilth and suitable seed bed. 除灭杂草 To kill weeds. 翻转耕层，翻埋残茬和肥料 To bury crop stubbles and fertilizers. 改变土壤耕层构造和地面状况，调节土壤水、肥、气、热因素，翻埋 根茬和肥料，清除田间杂草，控制土传病害，调节土壤微生物区系，为作物播种、出苗和生长发育提供适宜的土壤环境。 What is Soil Tilth?什么是耕层 指耕作措施经常作用的土层，也是作物根系分布最密集的层次。 The physical condition of the soil fitness for cultivation How is good soil tilth developed?如何创造适宜的耕层 适时、适法、 适度耕作 till at proper time, proper method and proper frequency to maintain proper aggregation. Too wet during tillage makes soil lumpy, too dry during tillage makes soil too fine and likely to blow; Over tillage will destroy soil structure and lead to soil compaction. What is a seedbed?什么是苗床 种子萌发和幼苗汲取营养之所在。 Place where seeds germinate nourish young plants. Seedbed Characteristics 要紧实，以便种子和根能够接触到土壤颗粒而吸收养分 must be firm to allow seed and root to come in contact with soil particles to absorb moisture； 要有足够的空隙以利于通气、扎根和水分运动 must be porous to allow air to move, root development, water movement. If soil is too loose, rain will wash away young plants； Air and water conduct heat more rapidly than soil, looser soils warm up sooner； Plant residue on surface insulates, warms up slower, also provides buffer against wind. What is the definition of a weed?什么是杂草 A plant that grows out of place -tillage can cut roots or bury weeds Is crop residue a benefit or detriment?作物残茬的利用 Definitely a benefit 当然是有益的 It helps control erosion, retain water, improve tilth 它有益于防止土壤侵蚀、保持水分、改良耕层土壤结构。 dark soils absorb light, warm up quicker; residue insulates, warms slower in wet areas soil is plowed; in dry areas leave residue What is primary tillage?什么是基本耕作 入土深、作用强烈、能显著改变耕层物理性状、后效较长的土壤耕作措施。一般在种植作物播种之前进行。 the