Rotations of crops

Koppelung,/. coupling linkage. Koppelwirtschaft, /. rotation of crops. Kopra-bl, -fett, n. coconut oil. 

Daubeny GGB. Memoir on the rotation of crops, and on the quantity of inorganic matters abstracted from the soil by various plants under different circumstances. Roy. Soc. (London) Phil. Trans. 1845 135 179-253. 

The total mineral constituents removed from the soil by this four years rotation of crops, will be, in pounds —... 

As different kinds of plants require for their development in some cases the same mineral substances, but in unequal quantities, a Boil may become barren for any one kind of plant, when by a series of crops one only of these constituents, as for example, soluble silica has been so far removed that the remaining quantity is no longer sufficient for a crop but it may still contain sufficient mineral constituents for another kind of crop which does not require soluble silica. A third sort of plant may thrive on the same soil after the second, if the remaining mineral constituents suffice for a crop of it. Upon thia fact depends the rotation of crops. 

Food production in the last few decades has been improved greatly by applying chemical fertilizers, irrigation methods, rotation of crops, and plant-breeding practices. Despite these new technologies for increased food production, the crop losses caused by insect pests, pathogens,... 

In the modern rotation of crops, plant growers plough under the leguminous crops or their nodule-producing roots which decay and enrich the soil with ample nitrogenous material to supply the next season s crop of nitrogen-consuming plants. 

Sclerotiiim, 426 stem (see Stem rot) of trees, shrubs, and vines, 238 Rotation of crops. See Crop rotation Rotenone, 481-82 Roundheaded appletree borers, 26, 318,318... 

Rhenish dynamite, 98, 112 Rigid cartridges, 103 Roburite, 103, 113 Rotation of crops, 4 Ruthenium, catalytic, 55... 

Herbicide resistant populations have evolved only in monoculture and/or mono-herbicide conditions at the rates we have previously predicted. Contrary to our original model, no populations of atrazine-resistant weeds have appeared in corn where rotations of crops and herbicides or herbicide mixtures were used. This is due to the previous lack of information about the greatly reduced fitness of the resistant individuals, which could be expressed only during rotational cycles, and also to the greater sensitivity of resistant individuals to other herbicides, pests and control practices. 

Tank mixtures of carbamothioates with atrazine or metolachlor reduced the expression of enhanced biodegradation (Tables V-VI). Other rotations of crops and or chemical classes can achieve the same results (4). 

Fusariosis, the disease caused by Fusarium toxins carmot be entirely prevented today. Improved agrotechnical, pest control and storage techniques collectively known as good agricultural practice can minimize the risk of fusariosis. Although some industrial processes can reduce the amounts of toxins, it is impossible to remove them entirely. Rotation of crops, appropriate soil treatment, fertihzation, and... 

For the first two rotations of crop rotation with balance of phosphoms of 943 kg/ha, the content of mobile phosphorus in soil increased Ifom 149 to 210 mg/kg, hence, the value of increment was 61 mg/kg. By the end of the fourth rotation, with balance of phosphorus of 523 kg/ha in siun for the third and the fourth rotations, even a decrease in the mobile phosphorus content in the arable layer was observed from 210 to 174 mg/kg, for example, by 36 mg/kg (Table 20.1, Figure 20.3). 

Studies of the Stavropol Scientific Research Institute of Agriculture [9] showed that in conditions of ordinary loamy chernozem annual fertilizer phosphorus application for crops of a six coarse rotation rate of N,2oP9oKj2o first rotation of crop rotation ensured positive phosphorus balance (the content of phosphorus was determined by the method of Machigin) 270 kg/ha (Table 20.2, Figure 20.5). 

Mobile phosphorus content in subsurface soil in the end of the rotation increased to 26 mg/kg or 13 mg/kg compared with the beginning of the rotation. During the second and third rotations at the same rate and the same total phosphorus balance 542 kg/ha mobile phosphorus content in the soil of the variant increased to 52 mg/kg, for example, 26 mg/kg compared with the beginning of the second rotation. But to the end of fifth rotation of crop rotation, for example, 12 years after the end of the third rotation in spite of systematic mineral fertilizer application at the same rate with phosphorus balance for these years 250-kg/ha mobile phosphorus content in the surface soil increased by only 2 mg/kg. 

Oats can be taken at almost any stage in a rotation of crops. They are a useful take-all break crop and are often a lower input crop than other cereals. 

Forage maize shottld form part of a rotation of crops. On some farms this may not be possible and maize may have to be grown for several years in the same fields. Where maize provides a very high (up to 100%) proportion of the winter bulk feed ration there may be no alternative to repeated cropping. 

---