Effect Of Cane-Leaf Returning On Sugarcane Growth And Some Soil Characters

Taken sugarcane variety of Yuanlin 6 as the experimental material, on the fieldcondition, applying CO(NH₂)₂ 40kg, CaO-MgO-P₂O₅ 75kg and KCL 15kg per666.7m², takenthe treatment without cane-leaf returning as the comparasion(CK), according to differentsugarcane leaf processing mode and time, four different cane-leaf returning treatments weremade: 1. residues left after harvest (including top department and leaves) were returned tothe field directly without any process, and as the base fertilizer(A treatment);2. residues leftafter harvest (including top department and leaves) were shatterd using mechanie andreturned to the field as the base fertilizer(B treatment); 3. residues were piled as compost andreturned to the field as stem fertilizer(C treatment); 4. leaves peeled in September andOctoberwere piled as the compost and returned to the field as base fertilizer(D treatment).Photosynthesis, physiological and biochemical characters, drought resistance, soil fertility,yield and quality of sugarcane were studied and results are shown as below:1. Growing dynamics of colonies: C shows the highest germination rate whichreached 54.20%, the second was A with 48.83%,the lowest one was treatment D, only 38.77%;For tiller rate, the highest one was treatment CK which was 31.83%, the second was C with27.63%, and the lowest was treatment B, only 13.60%. The fastest average growing rate in thewhole elongating period was treatment A and D, 1.90 cm/d, the next was treatment B,1.89cm/d, and the lowest was treatment CK, only 1.84cm/d; The number of productive stemsof C reached 4526/666.7m² which was the most of all treatments, the second was CK with4304/666.7m², and the lowest was treatment B, only 4176/666.7m².2. Photosynthesis index: changes of chlorophyll content of different treatment was similar: lower in the tiller period, heightest in the elongating period. For the netphotosynthesis rate, the content of CO₂ in cell and stomatal conductance, the result of fivetreatments had the same trends: lower in the tiller period, higher in star elongating period,the highest in fast elongating period, low in the later elongating period. D treatment's netphotosynthesis rate was lower than the others from tiller to fast elongating period, but higherin the later elongating period.3. Some physiological and biochemical indices related to sugarcane growth : Nitratereductase and acid invertase activity were lower in tiller period, and higher in the fastelongating period (C treatment's nitrate reductase activity was the highest and A treatment'sacid invertase activity was the highest), low in mature period. Neutrality invertase activity waslower in May to July, and highest in the early August (CK treatment's neutrality invertaseactivity was the highest), and turned low later.4. Effect on drought resistance: We studied some indices which relative to thesugarcane's drought resistance, includding field soil moisture, MDA, proline, cytoplasmmembrane penetrate character, relative water content and green leaf rate. In general, thecomparing order of drought resistance for all treatments was: D＞C＞A＞CK＞B.5. Effect on soil fertility: In the reseach, all treatments improveed the content ofavailable nitrogen in soil. C was the highest, improved 22.11mg/kg, A was the lowest, justimproved 1.00 mg/kg; the contents of available P of all treatments were declined; B declinedgreatestly declined 3.68mg/kg ; For K, all treatments were decreased except for C , Bdecreased greatestly for 37.72 mg/kg;Organic content of soil in CK and B were reduced, A,C and D treatments increased slightly; The pH values of soil in all treatments were increasedexcept for CK. Capacity of soil in B, C, D were reduced.6. The yield and quality of sugarcane:the highest yield of stems per 666.7m² wastreatment C of 7993.5 kg, the lowest was treatment B, only 7015.0 kg, in four treatments withcane-leaf returning (A, B, C, D). The difference between C and CK was significant; Thehighest content of sucrose was treatment B, with 15.21%, the lowest was treatment D, only15.07%; Glucose contents of all the treatments were lower than 0.25%; the gravity purity ofcane juice of all treatment was more than 85% and the rank was:A＞D＞C＞B＞CK. Thehighest sucrose per 666.7m² was treatment C of 1207.82 kg ; the lowest was treatment B, only 1066.98 kg. In four treatments with cane-leaf returning, the difference between D and CKreach the significant level.7. Summarize of the experiment: cane-leaf returning can fatten cane-field's soil,promote sugarcane's growth, improve the sugarcane's drought resistance and quality, promotethe sugarcane's high and steady yield. synthesizing all of surveyed result, In the experiment, Ctreatment was the best in the fatten cane-field's soil, and it's increased production and sucroseefect was the most significant.