Agriculture Reference
In-Depth Information
correlation with potassium (K) supply (Marin, 2009), Bangerth (1976) observed an increase in
vitamin C content of tomato fruits treated with calcium chloride. In this experiment, we do
not exclude the Ca factor when explained the improvement of tomato quality, while EM was
more likely to be the main factor, since EM had been reported to have effects on enhancing
crop photosynthesis, increasing crop protein contents, and improving crop quality (Daming,
1999; Shousong, 1998). Another evidence to support this speculation was that the soluble sugar
correlated negatively with calcium (Beckles, 2012). Taken as a whole, EM-Calcium application
significantly improved the fruit quality of tomato (evaluation indexes including vitamin C,
soluble sugar, soluble protein, and nitrate); meanwhile, foliar-spray proved to be a preferable
method when supplying EM-Calcium in this study.
The BER incidence may induced by the stresses in the root zone, such as salinity, soil water
stress, NH
4
+
toxicity and oxygen withholding (Saure, 2001; Tachibana, 1991), although the
impact mechanisms are not fully understood, these factors were considered either directly or
indirectly related to Ca
2+
deficiency: Tuna et al.(2007) reported that the exogenous
Ca
2+
application significantly improved growth and physiological variables affected by salt
stress, from another perspective, Adams (1990) showed that increasing the salinity above 4mS
cm
-1
by addition of major nutrients would reduce Ca content; According to some studies
(Albahou, 1999; Žanić et al., 2011), the increased proportions of NH
4
+
in standard nutrient
solution were often associated with severity of blossom-end rot known as a physiological
disorder of tomato fruit, and Siddiqi (2002) suggested that the NH
4
+
presence with a percentage
of 10% in total N reduced Ca
2+
accumulation; The BER occured commonly when the soil
moisture content was deficit or fully adequate (Adams, 1992, 1993), and there was a minimum
rate of transpiration relative to leaf growth rate below which calcium deficiency symptoms
were occured (Hamer, 2003); Tachibana (1991) also reported that withholding the oxygen
supply to roots at night was a cause of tomato BER, which greatly inhibited the absorption of
Ca. The negative correlation between Ca nutrient supply and BER incidence was also found
in this study, similar to many other studies (Besford, 1978; Mestre et al., 2012; Olle M, 2009). It
was concluded here that the BER incidence of different EM-Calcium treatments was
2.23%-13.39% lower than that of CK.
Fig. 5 showed the yield of marketable tomatoes, which was significantly increased by the
treatments except ST, Gezerel (1986) reported the application of foliar fertilizer containing
calcium of 0.2% increased the tomato yields and fruit weight. Mayer (2010) inferred that the
effects of EM preparation on crop yield increasing could be related to nutrient inputs by EM
carrier substrates. Hu and Qi (2013b) reported that long-term effective microorganisms
application could promote crop growth and increase yields and nutrition. In this study, we
deduced that EM alone had no obvious effects on crop yield, while it could enhance the
availability of nutrient supplied. Mestre et al.(2012) observed a negative and significant
correlation between fruit yield and BER (r=-0.810), our results showed that the BER incidence
had significant correlation with total tomato yield (r=-0.736) and marketable tomato yield
(r=-0.862).
Early study (del Amor and Marcelis, 2006) reported that Ca concentration of tomato plant was
significantly reduced by low-Ca supply (0.5 meq L
-1
) compared with the nutrient standard
