Fertiliser other nutrients

Others would extend the fertiliser concept to the simultaneous addition of readily biodegradable substrates along with the fertiliser nutrients to stimulate the growth of contaminant-degrading organisms most rapidly, and to aid in the rapid utilisation of the fertiliser nutrients before they might be leached from the contaminated area. The specific requirements for the most efficacious substrates is an area of current research. 

Weed competition for water and nutrients can have similar effects on fruit quality as described above for fertilisation. For example, if weed competition is completely prevented by chemosynthetic herbicides in conventional production, this can lead to excess supply of certain mineral nutrients, in particular nitrogen and potassium, which in turn results in reduced sensory quality and shelf-life (Section 16.2.2). On the other hand, excessive weed competition, in particular, during the pre-bloom phase and the end of the first shoot growth period (Gut and Weibel, 2005), can induce nutrient and/or water deficiency and a risk of quality loss. 

Some of the ammonia produced by the Haber process is used to produce nitric acid. If ammonia is then reacted with the nitric acid, we have the basic reaction for the production of many artificial fertilisers. The use of artificial fertilisers is essential if farmers are to produce sufficient crops to feed the ever-increasing world population. Crops remove nutrients from the soil as they grow these include nitrogen, phosphorus and potassium. Artificial fertilisers are added to the soil to replace these nutrients and others, such as calcium, magnesium, sodium, sulfur, copper and iron. Examples of nitrogenous fertilisers (those which contain nitrogen) are shown in Table 11.7. 

Of course there is a loss of information in the study of secondary and micronutrients (Ca, Mg, B, Fe, Mn, Cu and Zn). On the other hand the study would still be able to show whether the soils can supply these nutrients adequately to support any increased yield of grass due to the fertilisers or else that the grass becomes depleted in these nutrients. 

Dicalcium phosphate (anhydrous or sometimes as the dihydrate) has many uses. These include glass manufacture, plastics stabilisation, fertilisers and animal feeds. In addition, it is used as a dough additive, a nutrient and a dietary supplement. In pharmacy, it is used as a tablet diluent and dispersant calcium phosphates have other medical applications [32]. Other uses include paint and pigments and in toothpaste as a secondary abrasive. 

The mobility of P in soil is low compared with most other plant nutrients. The soluble P rarely travels more than 2-3 cm from the fertiliser granule before reaction with the soil, and so on. Because of this, the placing of the fertiliser in relation to the plant roots can be important in obtaining optimum efficiency. The band application of phosphatic fertilisers is sometimes practised. Diammonium phosphate solutions, for example, are injected at a distance below the surface, to suit the crop. 

In intensively cultivated areas, soil acidification from the nitrification process, following application of nitrogen fertilisers, far outweighs any effect from acid precipitation -Section 5.4.3. The potential loss of nutrients caused by this process are made up by application of the other fertilisers (Section 5.5). Only in the poor soils of pine and spruce forests is the acidification caused by acid precipitation substantial in relation to other sources. It may also be seen that forestry practices themselves can be a significant cause of soil acidification - Section 5.4.4. However, an important distinction should be made between organic acids formed from natural acidification processes, which are weak acids, and acidification... 

Farmers harvest crops to provide the world with food. Each year millions of tonnes of fertilisers are spread onto fields to replace the nitrogen and other plant nutrients lost from the soil. About 85% of the millions of tonnes of ammonia produced each year in the Haber process are used to make fertilisers. A relatively small amount of ammonia itself is used as fertiliser, mainly in the USA. This is injected into the soil. However, the vast majority of ammonia is reacted with acids to make solid ammonium salts. 

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