Evaluation Of Boron Release Characterization Of Boron Fertilizers Etibor-48 And Colemanite And Effects Of Them On Crops Yield And Quality

Boron (B) is an essential microelement for plant growth and development. The available B content of most of the soil of middle and lower reaches of Yangtze river in China is is very low. Oilseed rape, cotton, peanut, soybean are the main crops in this area, which showed sensitive to B deficiency. Therefore, the application of B fertilizer has become a standard measure in many B deficient regions nowadays,. The physical and chemical properties, the slow-releasing characterization, and improvement in crop yield and seed (grain, fruit) quality of two kinds of boron fertilizers, Etibor-48 (EB, Na2B4O7·5H2O) and Colemanite (CB, Ca2B6O11·5H2O) were investigated in this research.The main results are as follows:1 Boron release characterization of Boron Fertilizers EB and CBB desorption rate B, EB and CB increased with the rising of temperatures. The desorption rate of EB was lower than that of borax and far higher than that of CB. Thus, EB could keep a relative high B level for some time. CB is a slow-releasing boron fertilizer, especially suitable for sand soil. Double-parameter equation has the best fitting effect of B, EB and CB releasing dynamics curves at 10℃, and also best fitting of B and EB at 25℃and 40℃, thus parabolic diffusion equation and zero-order equation has of CB at 25℃and 40℃, respectively. Results of the boron leaching experiments showed that the trends of changes in soil available boron content of boron (B), EB and CB treatments were similar from January to December in a year, mainly appears as a rapid leaching before May. After May, the soil available boron content of EB and B treatments was under 0.3 mg/kg in purple-sand soil, however, between 0.3 mg/kg and 0.5 mg/kg in paddy soil. The soil available boron content of CB treatment was above 0.5mg/kg in both soils, which was higher than that of EB and B treatments. In addition, boron leaching was also influenced by rainfall and temperature besides boron fertilizer types and the soil texture.2 Effect of EB and CB on seed yield and seed quality of oilseed rape (Brassica napus) and their residual effectiveness for rotated riceThe effects of EB and CB on seed yield and seed quality of oilseed rape (Brassica napus) and their residual effectiveness for rotated rice were investigated in pot culture experiments and field trials, respectively. Seed yield of oilseed rape in the EB and CB treatments was significantly higher than that in-B treatment, and higher than that of B treatment for the first crop. Field trial results of the first crop (oilseed rape) in Anhui province, China, were consistent with those of the pot culture experiments. Grain yield of the second crop (rice) in all B fertilizer treatments was slightly higher than that of the-B treatment in the pot culture experiment; however, there was no significant difference in seed yield between EB and CB treatments and-B treatment in field trials in both Anhui and Hubei provinces. Pot culture experiments indicated that seed yield of the third crop (oilseed rape) was significantly lower than that of the first crop. In addition, there was no significant difference in seed yield of oilseed rape among the B fertilizer treatments, but seed yield in these treatments was significantly higher than that of the-B treatment. Seed yield of the third crop of oilseed rape in both B application treatments was also higher than that of the-B treatment and CB achieved the highest seed yield in field trials in Anhui province. Split plot experiments indicated that seed yield of oilseed rape in all B application treatments was slightly higher than that of each corresponding-B treatment for the third crop, and there was no significant difference in seed yield among the B application treatments. Residual effectiveness in the field trials conducted in Anhui and Hubei were not consistent, which could be attributed to a higher soil-available B content in the Hubei experimental plot than that in Anhui. For B deficient soils, B application can not only increase seed yield, but also improve seed quality of oilseed rape, whereas B application had little effect on grain quality of rice.3 Present and residual effectiveness of EB and CB on seed yield in three other rotation modesThis part presented effects of EB and CB on yield of peanut (Arachis hypogaea L.), cotton, soybean (Glycine max L.) and their residual effectiveness on seed yield for rotated oilseed rape (Brassica napus) by field trials. Results showed that basal application of B, CB and EB increased yield of peanut, cotton, soybean and oilseed rape in different extent. It indicated that the increasing rates of yield of peanut and oilseed rape could not increase with the increasing of B dosage, at potential boron deficiency. Seed yield of oilseed rape and cotton of EB and CB treatments didn't increase at Honghu, Hubei Province, but significant increased at Wangjiang, Anhui Province, thus the residual effectiveness for rotated oilseed rape of CB treatment is better than EB. Results showed that grain yield of soybean and seed yield of oilseed rape of EB and CB treatments increased during the soybean-oilseed rape experiments. The residual effectiveness of EB for the rotated two crops was better than that of CB and B. Double application of EB and B decreased the grain yield of soybean in the cropl, but increased seed yield of rotated oilseed rape. 4 Present and residual effectiveness of EB and CB on yield and quality of Shatin pomelo (Dicotyledoneae Rutaceae)The field trial was conducted to study effects and residual effectiveness of EB and CB on yield and quality of Shatin pomelo at Yangshuo, Guangxi Province from 2008 to 2010. Results showed that B application did not increase the fruit yield per plant of Shatin pomelo in 2008. There was no significant increasing in boron content of leaves of CB and B treatment, but a slightly increasing in EB treatment. Boron content of leaves of B application treatments was higher than that of-B treatment in 2009. In 2010, the fruit yield per plant of B application treatments increased and boron content of leaves were also significant higher than that in 2008 and 2009. Boron application could improve total water-soluble sugar content, but showed little effect on ascorbicacid and total acidity.