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|Title:||Effects of stillage application on cane and sugar yields and juice quality|
|Authors:||Marzola, Deo Lauro|
|Keywords:||Sugarcane -- Analysis|
Sugarcane -- Fertilizers
|Abstract:||A sugarcane field experiment was carried out to evaluate the effects of a range of K rates (0-1920 Kg/ha) from cane juice stillage (residue from alcohol production) applied broadcast or in the furrow and KCl on cane and sugar yields and juice quality. Determination of soil pH, AI, Ca, Mg, K, Na, and P and analyses of N, P, K, Ca, and Mg in the +3 leaf, 3-6 sheaths, and 8-10 internodes were made throughout the crop. At harvest, yield of primary stalks and tillers were recorded, juice analyzed for Pol, brix, reducing sugars, fiber and ash, and total nutrient uptake determined. Yields of cane and sugar increased up to 120 Kg K/ha from both stillage and KCl broadcast applications. At this K rate, soil K concentration at 15 days after application was 0.22 meq/100 g and +3 leaf, 3-6 sheath, and 8-10 internode K concentrations were 1.99 and 1.51, respectively, at 4 months and 0.98, 2.43, and 0.75, respectively, at 10 months of age. Since these soil and tissue K levels were associated with the highest statistical yields from K broadcast, it may be concluded that they are adequate for sugarcane growth. It was necessary to add approximately 100 m3 of stillage to supply 120 Kg of K. Rates of K from stillage up to 480 kg/ha appear to have no detrimental effects on cane and sugar yields. However, 960 and 1920 Kg K/ha from stillage increased cane, but decreased sugar yields and juice quality. These negative effects of high stillage rates on sugar yields seem to be related to the N added with stillage. Addition of dolomite with high stillage rates raised soil pH and increased stillage N mineralization resulting in lower plant N and higher juice quality. Ripener (Polaris) application 10 weeks prior to harvest also lowered plant N and improved juice quality. Stillage applied in the furrow immediately after planting at 240 Kg K/ha resulted in the highest yields. This was probably due to the increased germination, emergence and early growth rates observed in these treatments. Soil pH, Ca, Mg, and especially K increased with stillage application while soil Al decreased, particularly at high stillage rates. Application of high stillage rates may induce Ca and Mg deficiencies because more K is added relative to Ca and Mg which leads to a high K/Ca + Mg ratio. Application of dolomite improved this ratio resulting in higher yields. Leaching of soil K increased with increasing stillage application rates. Concentrations of Ca and Mg decreased whereas K increased in plant tissues with increasing K rates. Therefore, if high stillage rates are to be applied, soil Ca and Mg levels should be determined to predict possible deficiencies. The 3-6 sheaths and 8-10 internodes appeared to be the most sensitive to plant K, Ca, and Mg status. All three tissues were adequate for plant N. A sugarcane yield response curve to K fertilization may be used to determine the amount of stillage K to be applied. In addition, since stillage N and K composition are highly variable, these should be determined to quantify the amounts of these nutrients supplied by stillage. If high amounts of stillage are to be applied for waste management, problems such as difficulty in cane ripening, lower juice quality and soil salinization should be considered. However, ripener application can overcome the delayed ripening and improve juice quality.|
Thesis (Ph. D.)--University of Hawaii at Manoa, 1984.
Bibliography: leaves -179.
xv, 179 leaves, bound ill. 29 cm
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|Appears in Collections:||Ph.D. - Agronomy and Soil Science|
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