Parâmetros fisiológicos, químicos e biológicos da cana-de-açúcar (Saccharum spp.) em solo cambissolo eutrófico sob condições de colheita com e sem queimada

Abstract

CHAPTER I: In a Inceptisol soil, at Santa Cruz Sugar Mill, Campos dos Goytacazes/RJ, an experiment was conducted with the purpose to evaluate, during the cycle of second ratoon answers to the application of sugarcane agroindustry wastes, in consitions of harverst management with and without previous burning, using the growth quantitative analysis and utilizing the RB72454 sugarcane variety. The experimental field was planted in April 1992. The plant cane cut ocurred in July 1993. The first ratoon was harvested in August 1994, when the test was reinstalled to evaluation in the second ratoon, which harvest was in September 1995. The tested treatment were: 1 = CC = raw cane; 2 – CC + TF = raw cane + 30 t.ha-1 of filter cake; 3 – CC + TF + B = raw cane + 20 tons of filter cake ha-1 + 10 t.ha-1 of bagasse; 4 – CQ = burned cane; 5 – CQ + TF = burned cane + 30 t.ha-1 of filter cake; 6 – CQ + TF + B = burned cane + 20 t.ha-1 of filter cake + 10 t.ha-1 of bagasse. The physiological rates discussed and interpreted were: a) Number of stalks by linear meter; b) Stalk height (m); c) Total biomass (g.m-2 soil); d) Leaf area index (m2 leaf. m-2 soil); e) Growth tax of the cultural (g.m-2 leaf. day-1); f) Liquid assimilation tax (g.m-2 leaf.day-1); g) Leaf nitrogen concentration; h) Stalk nitrogen concentration. The results allowed the following conclusions: 1) The application of the sugar agroindustry wastes (filter cake and bagasse) in areas harvest with or without burning, didn’t increased the stalks number and canes height. 2) The fact of not have significant differences to the stalks number rates by linear meters and canes height, reflected directly in a not statistical difference among the evaluated treatments, beeing relative a industrial stalks final productivity in t.ha. 3) The value of total biomass, obtained in the various treatments, was very low, mainly in function of hydric deficit ocurred in the period of the development of the experiment. 4) O I.A.F. (leaf area index), showed little significant changes in the first samples (second, fourth and sixth months), with higher values to burning treatments, in function of a higher stalks number by meter found in this parcels. 5) The straw index calculated (20, 6 t.ha-1) affected the ratoon budding, lowing the stalks population. 6) The leaf area index stayed lower than that considered ideal to the development of a productive sugarcane plantation, correlating with the law productivity obtained, beeing a good physiological parameter to the estimation of a sugarcane’s production. 7) The growth tax of the culture showed the highest values between 120 e 240 days after cut, similar to all treatments during the vegetative development cycle and coincided to the highest foliar area index. 8) The liquid assimilation tax was affected by the hydric stress in the period of the maximum growth of the culture. 9) The nitrogen leafs concentration, as the nitrogen stalks concentration didn’t show differences among the treatments. The fact that the soil studied was a Inceptisol soil, with great natural fertility and that ocurred a great hydric stress during the culture cycle, may have equalized the answers. -------------------------------------------------------------------- CHAPTER II: In a Inceptisol soil of Santa Cruz sugar mill; located at Campos dos Goytacazes,RJ, an experiment was conducted to evaluate the influence, in the chemical and biological properties of the soil, during the sugar cane second ratoon, of the sugar industry wastes (filter cake and bagasse) applied into experimental parcels harvested with and without previous burning of the cane. The experimental field was planted in April 1992. The harvest of the cane ocurred in July 1993. The first 1994, ratoon was harvested in August when the experiment was reinstalled for evaluation in the second ratoon, which harvest was done in September 1995. The tested treatments were: 1= CC= raw cane; 2- CC+TF= raw cane + 30 t.ha -1 of filter cake; 3-CC+TF+B= raw cane + 20 tons of filter cake ha-1 + 10 t. ha-1 of bagasse; 4-CQ= burned cane; 5- CQ +TF= burned cane + 30 t ha-1 of filter cake; 6-CQ + TF + B= burned cane + 20 t.ha-1 of filter cake + 10 T.ha-1 of bagasse. The parameters discussed and interpreted were: a) manufacturable stalks productivity in t.ha-1; b) Sugar production in t Pol ha -1; c) microbial soil biomass-carbon in mgCg -1 of soil; d) agroindustrial wastes effect among treatments on the productivity of second and the third curts of the in t.sugarcane ha-1; e) treatments effects on soil chemical properties; f)straw index determination. The results allowed the following conclusions: 1- The application of the sugar agroindustry wastes (filter cake and bagasse), in the sugar cane fields harvested with or without burning, didn`t result in increasing of productivity, in t.ha-1 or in t.ha-1. 2- Raw cane treatments, that received industrial wastes, showed expressive higher values of BMS-C, in comparison with burned cane treatments, mainly in raw cane treatment with filter cake. 3- The Inceptisol soil, may have facilitaded the similarity of the production results (t cane ha-1), due to the its high natural fertility. 4- Straw index, equivalent to 20,6 t. straw ha, may have affected the ratoon budding of the raw cane treatments. 5- generally speaking, the soil chemical properties studied haven`t been modified when the treatments are compared.