Author
 |
Lingle, Sarah |
|
Wiegand, Craig |
|
Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/18/1997 Publication Date: N/A Citation: N/A Interpretive Summary: Salt in soil is an increasing problem in many areas where crops are grown, especially where irrigation must be used. The effect of soil salinity on sugarcane was determined by measuring juice quality on stalks from a salt-affected field in commercial production. Increasing salinity decreased all quality parameters that influence how much sucrose can be recovered from sugarcane. In addition, specific salts in the soil accumulated to high concentrations in sugarcane juice. High concentrations of any chemical not sucrose interferes with the ability to recover sucrose during processing. Results of this study suggest that the sugarcane plant can hold only so much stuff in its stalk, and if that stuff is salt because of high soil salinity, then the plant cannot accumulate as much sucrose. One possible way to address this would be to find sugarcane types that do not accumulate as much salt, even when grown in salty soil. Another way would be to avoid salt-affected fields when planting sugarcane, and plant more salt-tolerant crops instead. Technical Abstract: The effects of soil salinity on sugarcane (Saccharum spp. hybrids) juice quality were examined during a two-year period. A salt-affected commercial field of 'CP 70-321' sugarcane was used for the experiment. Electrical conductivity of saturated water extracts of soil samples from 0 to 30, 30 to 60, and 60 to 90 cm depths was used to calculate weighted electrical conductivity (WEC) of the root zone. WEC in the field ranged from 0.46 to 12.74 dS m-1.Increased WEC decreased percent soluble solids (RFS; r2=0.876) and percent sucrose (Pol; r2=0.483) in the juice. There was a reduction in juice purity (sucrose percent total soluble solids) with WEC (r2=0.463) only in the second year. Juice conductivity increased with soil salinity (r2=0.592), but the osmolality of the juice was not significantly affected. Cane percent fiber, determined only in the second year, increased with soil salinity (r2=0.434). Sugar yield per tonne cane and per hectare were also reduced by WEC in both years. In this study, sodium and calcium were the most abundant cations in the soil extracts (ranges 0.05 to 1.59 g L-1 and 0.05 to 0.87 g L-1, respectively), but potassium was the most abundant cation in the sugarcane juice (2.05 to 4.20 g L-1). There was a weak curvilinear(R2=0.346) relationship between juice potassium and WEC, while juice sodium concentration increased with WEC from 0.11 to 0.86 g L-1 (R2=0.718). Magnesium and calcium were also present in the juice, and increased with WEC (R2=0.572 and 0.486, respectively). All juice cations were significantly correlated with each other and with soil cations. For most attributes, there were no significant differences between years. |
