RESPONSES OF SOME SUGARCANE VARIETIES TO STANDARD AND COMBINATION RIPENER TREATMENTS
The effects on sucrose yield of varying the time interval between Ethrel and Fusilade Super applications in a com­ bination treatment were tested on variety NC0376. Results suggested that Ethrel applied 12 weeks, and Fusilade Super applied eight weeks before harvesting were the most bene­ ficial. Other varieties which responded to a combination treatment were N19, N12 and N22. Varieties N14, N19, N17, N12, N22 and NC0376 grown under irrigation all re­ sponded to one of the ripener treatments, and their responses to Ethrel and Fusilade Super are discussed. There were no significant gains in sucrose yield of CP66/1043 in response to the ripeners although sucrose content was increased.
Chemical ripening of sugarcane: global progress and recent developments in China
Chemical ripening of sugarcane is a well established practice to enhance sucrose content in many sugarcane growing countries. Chemical ripeners such as Ethephon, Glyphosate analogues, Fusilade Super, Gallant Super are being used in large scale sugarcane plantations. The gains in sucrose content in sugarcane have been reported from 0.5-2.0 units, depending upon variety-weather-ripener interaction. In mainland China, many chemicals with ripeners like properties such as Lanthanium rich rare earth mixture, lime water, potassium di hydrogen phosphate etc. have been tried. Duoxiaohao- a product consisted of multiple nutrient elements also showed good results in improving plant growth and sugar accumulation in sugarcane. However, the best results have been obtained with glyphosate-borate complex which was effective even under water deficit stress and did not affect sprouting of subsequent ratoon crop. The average improvement in pol% cane was over 1.0 unit. Due to its commercial benefits, it has been popularized in large scale of sugarcane plantations in Guangxi Province and at present about 20,000 hectares have been brought under chemical ripening using glyphosate-borate aerial spray.
Investigations on the rôle of organic matter in plant nutrition
1. As the result of decomposition of green manure in a swamp soil, the coarse fractions (including coarse and fine sand) of the surface layer (first 3 inches) decreased by 11·2 per cent. while the fine ones (silt+clay) increased by 9·8 per cent. in the course of 43 days. The effect was less pronounced in the manured soil maintained at 60 per cent. saturation, while no alteration was to be noticed in the case of the unmanured specimens. 2. Treatment with dilute hydrochloric acid prior to dispersion had no appreciable effect on the estimates of mechanical composition obtained in the different cases. Loss in solution was also comparatively small. 3. The silica-sesquioxide ratio increased slightly as the result of decomposition of green manure in swamp soil. The composition of the fine fractions was also altered, the total percentages of the oxides of iron, aluminium and silicon increasing from 90·5 to 99·3 in the course of 71 days. 4. The practical significance of the above and related observations has been discussed.