Agriculture Reference
In-Depth Information
Application of Active EM-Calcium in Green Agricultural Production — Case Study in Tomato and…
http://dx.doi.org/10.5772/58329
2.3. Discussions
Calcium is well known for having regulatory roles in metabolism and sodium ions may
compete with calcium ions for membranebinding sites (Tuna et al., 2007), and is also known
to bind to phospholipids and proteins on the membrane surface, which is required to maintain
proper membrane structure and integrity (Jones and Lunt, 1967; Suzuki et al., 2003), thus to
some degree, high calcium levels can protect the cell membrane from the adverse effects. In
view of the important role calcium played, much emphasis was put on the exogenous Ca
application for plants. In the choice of Ca nutrient solution for tomato, materials such as
CaSO
4
2H
2
O (Hall, 1977), CaNO
3
4H
2
O (Eraslan et al., 2007; Murillo-Amador et al., 2006),
CaCl
2
(Dong Cai-xia, 2001; Schmitz-Eiberger et al., 2002; Xu et al., 2010), CaO (Almeida et al.,
2009; Asiegbu and Uzo, 1983) had been selected as Ca resources for different studies. Before
preparing the Ca solution in this study, the activity of Ca ions and cost of the calcium solution
were mainly taken into consideration during the selection process of materials, we tried to
mixed the gypsum with EM previously, while it was found that the solubility of gypsum in
EM was not satisfactory compared to that of lime, the lime was finally selected as the Ca
resource. Before the experiment we also concerned about whether the Ca
2+
suspension made
by lime would change the survival environment of the acid-loving effective microbes, results
proved later that the pH of the mixed liquor fallen back to suitable levels after several days'
fermentation. Under microbial actions, the solubility of calcium in EM obtained a satisfactory
result (maximum Ca
2+
solubility of 89.50%), while with the increasing application of lime, EM,
and molasses, the dissolving capacity of calcium presented a decline trend, it was predicted
that the measured Ca
2+
concentration of the EM-Calcium solution would stay in a certain value
and the solubility of calcium would decrease with the increasing of raw materials. According
to the results of the lab experiment, the mixture of Ca
2+
suspension/ EM/ molasses/ DI water
with a volume ratio of 3: 1.5: 1.5: 4 was recommended to practice.
Recent studies tented to adopt foliar-sprayed method on the exogenous Ca application for
tomato plants (Eraslan et al., 2007; Gezerel, 1986; Murillo-Amador et al., 2006); there were also
experiments (Tabatabaie et al., 2004) about the use of solutions of different concentrations
applied to different parts of tomato root system. This experiment showed that the foliar-
sprayed method was most beneficial for the Ca accumulation of tomato fruits according to
Table 4, spraying EM-Calcium solution on plant leaves increased the Alc-Ca, H
2
O-Ca, NaCl-
Ca, HAC-Ca contents of tomato fruits more significantly than spraying on the other organs,
increment of NaCl-Ca content (calcium pectate) was especially notable, this might be related
to the increases of soluble pectin in tomato fruits with the ripening of tomatoes (Ashraf M,
1981). Spraying the calcium nutrition on surface of fruits such as litchi, sweet cherry and grape
proved not to be an effective way (Combrink, 1995; Huang et al., 2008; Koffmann, 1996), while
for tomato fruits in this experiment, results showed that EM-Calcium application had no
significant effects on the Ca increment in old tomato fruit, while which had significant effects
on the Ca increment in young tomato fruit.
Vitamin C acts as an antioxidant in plants and its levels are responsive to a variety of envi‐
ronmental or stress factors, for example light, temperature, salt and drought, atmospheric
pollutants, metals or herbicides (Singh et al., 2012), and which was reported having positive
