Sandy soils cropping

Seed germination reduced 50% (Kulshrestha etal. 1982) Effectively controls weeds in wet sandy soils some damage to crop possible in dry clay soils (Amor et al. 1987)... 

Hi. Because PRs are natural minerals requiring minimum processing they are environmental benign (Schultz 1992) and iv. PRs could be more efficient than soluble fertilizers in terms of recovery of phosphate by plants, even for short term crops in soils where soluble P is readily leached, as in sandy soils (Yeates and Clarke 1993) and possibly for long-term crops also in other soils (Rajan et al. 1994). 

Nitrous oxide emissions are generally induced by fertiliser application. Emission strength varies with soil type, temperature and moisture and is substantially crop specific. There is a considerable difference between woody species and cereals. While the Intergovernmental Panel on Climate Change (IPCC) general N20 emission value is set to 1.25% of the nitrogen applied an average of 0.8 to 1.0% could be found from sandy soils. 

Fig. 5.4 Long-term impact of reduced nitrogen fertilisation on the yield of whole crop cereals and SRCs on a sandy soil in Germany (relative yield related to the yield of an application rate of 150 kg N ha-1). The reduction of the N application rate by 50% results in a mean relative yield loss of -10% after 15 years for rye and triticale. Non-fertilisation cause significantly higher losses. By contrast, the relative yields of poplar and willow on reduced and even non-fertilised stands do not decrease, but instead increase, although the absolute yields grow over time. One of the reasons for this phenomenon seems to be mycorrhica...

Reliable long-term measurements have been performed by Hellebrand et al. (2008). They measured the N20 emissions on different fertilised energy crop plots on a sandy soil over a period of 9 years and found differences not only between the various fertilisation levels, but also between the crop species. In spite of the yearly spread it can be summarised that SRCs cause less N20 than cereals and grass. So the N20 emissions rate on non-fertilised poplar and willow fields is only 17-26% of the rate on conventionally fertilised cereal fields (Fig. 5.5). 

Fig. 5.5 Crop-specific N20-N emissions with and without hotspots for different N fertilising rates according to Hellebrand et al. (2008), continuously measured for up to 9 years on sandy soil in Germany. The additional N20 emissions caused by the hotspots are not insignificant. However, the reason for these irregular increases is not yet clear...

Copper deficiency in plants is most frequent on organic soils, such as newly drained bogs, and on very sandy soils The severe copper deficiency often found when bogs and marshes are first used for crop production is called nyUinutliori disease in some parts of the world. 

In the United States, severe iron deficiency in crop planls occurs most frequently on the alkaline soils of the western stales and on v ery sandy soils, although some plants, especially hroad-leaved evergreens, are sometimes iron deficient on many other kinds of soils. Iron deficiency is rarely due to t total lack of iron in the soil. It is nearly always due to die low solubility of the iron that is present. For example, some soils that arc red from iron compounds may contain too little available iron for normal planl growth. The relative susceptibilities of cultivated crops to iron deficiency arc listed in Tabic I. 

Lobe, I, Du Preez, C. C., and Amelunga, W. (2002). Influence of prolonged arable cropping on lignin compounds in sandy soils of the South African Highveld. Eur. I. Soil Sci. 53, 553-562. 

Hellebrandt H.J. Kern J. and Scholz V. (2003). Long-term studies on greenhouse gas fluxes during cultivation of energy crops on sandy soils. Atmospheric Environment, 37(12), 1635-1644. 

Scholz, V. and Ellerbrock, R., The growth, productivity, and environmental impact of the cultivation of energy crops on sandy soil in Germany, Biomass Bioenergy, 23, 81-92, 2002. 

Three factors determine how much brine can be disposed of in a field, assuming that the brine does not contain boron. The first factor is the type of crop crown. Different crops tolerate different levels of salt. For example, some clovers are extremely sensitive to salt, while some grasses, like tall fescue, are quite tolerant (Table 11.2). The second factor is the CEC of the soil. A soil with a CEC of 10 meq 100 g-1 can tolerate approximately 460 lb of sodium per acre (10% of CEC) before it reaches its critical toxicity threshold. However, a soil with a CEC of 20 meq 100 g 1 can tolerate up to 920 lb of sodium per acre before it reaches its critical threshold. The third factor is the texture of the soil. A sandy soil can take very little sodium chloride salt before it... 

Insecticides tend to persist longer in soils of high organic matter. In fact, in muck soils (50% or more organic matter), residues have been found bound to soil particles to such an extent that the same amount of toxicant is less effective in muck soil as compared with a sandy type. It has been noted that pesticides are absorbed into crops most readily from sandy soils and least from muck soils. Moisture enhances the release of volatile pesticides from soil particles and also influences the breakdown of other toxicants. Microbial attack has been found to oxidize aldrin to dieldrin, and parathion in the presence of yeast is reduced to the nontoxic aminoparathion in soil. As might be expected, increased soil temperatures can dramatically increase the rate of pesticide loss owing to volatilization and increased breakdown. Cover crops, such as alfalfa, can decrease pesticide volatility from soil whereas cultivation... 

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