Effect Of Combined Application Of Potassium And Sulfur On Canola Yield And Nutrient Absorption

In order to study the effect of combined application of potassium and sulfur on canola yield,nutrient absorption and soil nutrient changes,a field experiment was conducted on the experimental farm of Huazhong Agricultural University in 2007-2008, by adopting Zhongyouza 11 as the material.The results were as follow:1,Effect on canola seedling quality before winterThe results indicated that in case of no sulfur applied,canola seedling height could increase with increasing application of potassium fertilizer.Seedling height of S0K3 treatment increased by 10.07%compared to that of S0K0 treatment;but increasing potassium didn't significantly affect collar diameter,seedling diameter and greenery number.In case of sulfur applied,increased potassium inhibited seedling height and collar diameter,lowered seedling diameter,but did not significantly affect the greenery number.2,Effect on canola yield and its componentsUnder the same sulfur fertilizer treatment,canola yield gradually increased with the increase of potassium supply,the differences between treatments were extremely significant,the treatment of the highest canola yield(4156.73kg/hm~2) was S1K3,the treatment of the lowest canola yield(3168.30kg/hm~2) was S0K0.Under the same potassium treatment,compared with non-application of sulfur fertilizer,canola yield increased with application of sulfur fertilizer;for K0,K1,K2 and K3 levels,canola yield were increased 9.19%,4.50%,2.34%and 5.75%respectively.No sulfur application, increasing application of potassium rate can increase 1000-grain weight,while not significantly affect pod number of main inflorescence,total pods of plant and number of seed per pod;under the application of sulfur,increase application of potassium can increase pod number of main inflorescence and lower 1000-seed weight,but not significantly affect total pods of plant and number of seed per pod.3,Effect on nutrient absorptionUnder the same sulfur supply,the total content of nitrogen and potassium of canola gradually increased with the increasing of potassium application rate during the whole growth period,while total phosphorus and sulfur content showed no apparent rule. Whether application of sulfur or not,have little impact on the total nitrogen,phosphorus, potassium and sulfur content.The total content of nitrogen and phosphorus of leaf gradually increased at seedling stage,while gradually declined after the seedling stage; the total content of potassium gradually decreased at seedling stage,but sharply declined in the later bolting stage;the total sulfur content of leaf didn't change largely at seedling stage,but gradually decreased at bolting stage,then gradually increased from the later bolting stage to full-blooming stage.4,Effect on soil nutrientDifferent sulfur and potassium fertilizer treatments have little impact on soil total nitrogen,phosphorus and available phosphorus,but have some impact on soil total potassium and available potassium,and have significant impact on soil available sulfur. Compared with no sulfur application,the absorption of soil nitrogen and potassium was enhanced by sulfur application;sulfur application can increase the soil available sulfur content;the effect of potassium on soil nutrients was not obvious.On the total quantity change of soil nutrient content,all nutrient contents are gradually reduced except for soil available phosphorus.