Tillage importance

Fertilizer Use. The worldwide use of fertilizers has an important, positive effect on the environment. Conservative estimates (112) iadicate that about 30% of world food production is direcdy attributable to fertilizer use. Without fertilizer, therefore, at least 30% mote virgin land would have to be devoted to agriculture, and 30% more labor and other resources would have to be expended. Even more serious would be the effects of land tillage and cropping without nutrient replenishment. Past experience has shown that, under such a condition, crop yields progressively decrease, the land eventually becomes barren, and forces of wiad and water erosion prevail. 

A review of the available literature allows a hierarchical ranking of the importance of different factors that influence the pre-harvest infection of cereal grains by Fusarium weather/climate (year) > inoculum pressure/tillage/ previous crop > fungicides > available plant nitrogen. The individual factors related to other fungi are described in separate sections below. 

Rizvi SJH, Mishra GP, Rizvi V (1989) AUelopathic effects of nicotine on maize I. Its possible importance in crop rotation. Plant Soil 116 289-291 Roshchina VV (2001) Molecular-cellular mechanisms in pollen allelopathy. Allelopathy J 8 11-28 Roth CM, Shroyer JP, Paulsen GM (2000) Allelopathy of sorghum on wheat under several tillage systems. Agron J 92 855-860... 

After these steps are acconq>lished, it should be possible to survey for the organisms, to relate their abundance to management practices such as tillage and rotation, and to develop management alternatives to reduce their inq>acts. Importantly, more trials of bacteria-treated seed are necessary to determine the precise agronomic importance of these organisms. 

The relative importance of the pros and cons of tillage in a given environment should... 

Conventional tillage exposes the OM, which are naturally stabilized in the soil, to the action of sunlight and oxidation conditions that favor microbial activity. Consequently, only the very stable fraction of SOM generally remains. The importance of SOM functions is well known, but structural information, chemical composition, and changes induced by anthropogenic factors, such as tillage practices, are still under research. 

The benefits of the triazines in multiple cropping systems range from their application flexibility, effective weed control, soil residual activity, and crop selectivity to their important role in resistance management and conservation tillage. The triazines also have made a major impact on agricultural sustainability and crop yields, as evidenced by the use of atrazine, especially in com. 

Seeds are an important food source for many insects, birds, and small mammals. Seed predation is usually less in agricultural systems due to the intensive soil disturbance, seed burial by tillage, and lack of habitats for predators. However, studies have found significant weed seed loss by predation when seeds remained on the soil surface. 

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