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The Effect of Crop Sequence on Erosion Under Individual Crops
Author(s) -
Smith Dwight D.
Publication year - 1947
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1947.036159950011000c0098x
Subject(s) - soil conservation , crop , agriculture , service (business) , presentation (obstetrics) , citation , tillage , cover crop , mathematics , library science , sociology , agricultural science , computer science , political science , agroforestry , archaeology , environmental science , history , geography , business , agronomy , forestry , biology , marketing , medicine , radiology
sequence is the transition from one crop to _ another within a rotation or cropping system. This factor determines to a large degree the erosional characteristics of a given crop rotation. The two elements of crop sequence that effectuate the control it provides are (a) soil conditioning and (b) crop cover protection for the soil. Crop sequence is a very usable means of securing erosion control, and, as such, it may be considered an erosion control practice. It is essential that it be considered in the development of conservation farming plans along with fertilitybuilding treatments, contouring, terracing, or strip cropping. A study of the erosion process and of rainfall characteristics reveals why the two elements of crop sequence are so essential to control of erosion. Ellison (3) has stated that the primary cause of sheet erosion is, rainfall impact and associated raindrop splash. Borst ( i) has shown that the absorption of the energy of the falling rain .on a surface mulch of straw would nearly eliminate erosion. This is particularly true on relatively flat slopes where runoff does not attain a velocity of high magnitude. It is, of course, not possible to provide a continuous or a sufficiently dense plant cover, at all periods of the year if different crops are to be grown. Proper crop sequence will limit the number and extent of these periods. When they do occur, minimum erosion can be assured only if the soil has been properly conditioned. Soil conditioning refers to a combination of factors that may act to limit erosion when the soil is without plant cover protection. Stability of aggregation is probably the most important. It is related to the organic matter content (2) of the soil. The presence of undecayed grass roots and stems is an important factor. Infiltration capacity and percolation rates are also involved. Rainfall has the capacity to do a tremendous amount of work on the .soil surface. Calculations based on published literature (6, 7, 9) show that 58% of the annual central Missouri rainfall on i acre of land contains nearly 60,000,000' foot pounds of energy. This .is 2:5 times the energy required to plow I acre of Putnam soil, or 24% more than that required to produce an acre o'f corn (5). The average intensity of the rainfall used in these calculations was O.66 inch per hour. It was all of the rain that fell at an intensity of 0.19 inch per hour of greater. This paper will present the results of crop sequence studies on the Missouri Soil Conservation Experiment Farm near McCredie, Mo., during the 5-year period 1941-45 and show how this type of data may be used for the scientific design of soil-conserving cropping systems.