FANR 3060 1st Edition Lecture 11Outline of Last LectureI. Soil Physical PropertiesII. Soil TextureIII. Soil StructureIV. Soil DensityOutline of Current LectureI. Soil Density con’tII. Managing Soil Physical PropertiesChapter 4I. SoilDensity con’ta. Pore spacei. Micropores1. Finer pores within aggregates 2. Water storage poresa. Don’t drain after rainb. Sandy soilsi. Coarseii. Coastal plainsiii. Lots of macropores, little to no microporesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.iv. Good water flow, good aerationv. Poor water holding capacity1. Needs irrigationvi. Easy to till and manage; best soils for agriculturec. Fine soilsi. High in micropores, variable amounts of macroporesii. High water holding capacity1. Best: sandy loam, loam, and silty loamiii. Amount of macropores depends on structure1. Good structure = okay water flow and aeration2. Bad structure = stays wet, poor aerationd. Humusi. High water holding capacity1. Can add to sandy soils to make them more desirableII. Managing Soil Physical Propertiesa. Poor physical condition of topsoil (tilth) reduces root growth and vigor, which then reduces plant performance and growthi. Avoid compactionii. Break up dense layers1. Deep tillageiii. Till only when necessary1. Preserve aggregates and humusiv. Add humus1. Residues, manure, wastea. Add over a period of time, not all at once2. Improve structure of fine-textured soils3. Increase water holding capacity in sandy soils b. You can’t change texture of soili. Acre-furrow slice1. Depth of tillage over an acrec. You can change structure of soili. Either mess it up or improve it1. Very important in fine-textured soilsii. Tillage1. Too much, or doing it when it’s too wet or dry, can break down aggregatesa. Aggregates are formed by root action and interaction with humus2. Humus is reduced with tillage, and aggregates are weakeneda. The humus gets oxidizedd. No-till agriculturei. Plant into residue from last year’s cropsii. Reduced run off, erosioniii. Improved infiltrationiv. More weeds1. Forced to use herbicides to