Diseases and Management of Crops under Protected Cultivation
Diseases and Management of Crops under Protected Cultivation
Diseases and Management of Crops under Protected Cultivation
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Quantity in MT<br />
(<strong>Diseases</strong> <strong>and</strong> <strong>Management</strong> <strong>of</strong> <strong>Crops</strong> <strong>under</strong> <strong>Protected</strong> <strong>Cultivation</strong>)<br />
therefore it is safer to keep the fertilizer concentration <strong>of</strong> 1-2% in the irrigation water during<br />
fertigation.<br />
Water soluble specialty fertilizers<br />
A specialty fertilizer is a concept. The crux is to inculcate intangible concept initially which<br />
eventually leads to tangible results (Goel, 2007). These fertilizers are fully water soluble solid<br />
fertilizers. They have high content <strong>of</strong> primary nutrients with low salt index. They may or may not<br />
have secondary / micro nutrients. These water soluble fertilizers can be advantageously utilized for<br />
foliar feeding <strong>and</strong> fertigation, thus helping in precision agriculture. Since it is concept it has to be<br />
viewed differently with a different approach. In order to use the marketing strength effectively <strong>and</strong><br />
also to capture critical mass, this business into three segments i.e. foliar application, fertigation<br />
<strong>and</strong> soil application. The market size <strong>of</strong> water soluble fertilizers in India is presented in Fig.1.<br />
80000<br />
70000<br />
60000<br />
Fertigation<br />
Foliar<br />
Total<br />
50000<br />
40000<br />
30000<br />
20000<br />
10000<br />
0<br />
1999-00 2000-01 2001-02 2002-03 2003-04 2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 2010-11<br />
Years<br />
Fig 1. Market size <strong>of</strong> water soluble fertiliser in India<br />
4. Important Points to be considered during Fertigation<br />
Water quality: The interaction <strong>of</strong> water having pH values (7.2 -8.5) with fertilizers can cause<br />
diverse problems, such as formation <strong>of</strong> precipitates in the fertilization tank <strong>and</strong> clogging <strong>of</strong> the<br />
drippers <strong>and</strong> filters. In waters with high calcium content <strong>and</strong> bicarbonates, use <strong>of</strong> sulphate<br />
fertilizers causes the precipitation <strong>of</strong> CaSO 4 obtruding drippers <strong>and</strong> filters. The use <strong>of</strong> urea induces<br />
the precipitation <strong>of</strong> CaCO 3 because the urea increases pH. The presence <strong>of</strong> high concentrations <strong>of</strong><br />
calcium <strong>and</strong> magnesium <strong>and</strong> high pH values lead to the precipitation <strong>of</strong> calcium <strong>and</strong> magnesium<br />
phosphates. Recycled waters are particularly susceptible to precipitation due to its high<br />
bicarbonate <strong>and</strong> organic matter content. The resultant precipitates are deposited on pipe walls <strong>and</strong><br />
in orifices <strong>of</strong> drippers <strong>and</strong> can completely plug the irrigation system. At the same time, P supply to<br />
- 126 -
Change language