Effects of combined application of chemical fertilizers with different sources of organic manure on the grain quality of winter wheat

Objectives The objectives of this study were to improve winter wheat grain quality and provide a theoretical basis for efficiently using different types of organic fertilizers by optimizing fertilization techniques.

Methods A field experiment was conducted in whinter wheat using chicken fest, pig manure and cattle manure as orgain N resources. At base of total N input of 225 kg/hm², single applicaion of chicken, pig and cattle manure and urea, combined application of the three manures with urea in ratio of 25%, 50% and 75%, and the double single N input treatments (total 18 treatments) were designed. Three wheat grain indexes, 5 flour indexes, and 7 dough indexes were measured. Principal component and cluster analyses were applied to assess the effects of different fertilization treatments in wheat quality.

Results At the N input level of 225 kg/hm², single application of chicken and pig manure had the same effect on wheat quality with urea, and distinctly superior to cattle manure. Compared with the cattle manure, the average dough development time of applying chicken manure, pig manure, or chemical fertilizer alone was extended by 50.85%. As well, the average farinogram quality number was increased by 25.75%, the average wet gluten was increased by 19.71%, the average sedimentation value increased by 18.17%, the average crude protein content increased by 14.37%, and the average dough viscoelastic ratio decreased by 36.84%. When N input was doubled, the wheat quality indices were not increased obviously. In the urea and manure combination treatments, lower manure proportion (25%) were more effective to increase grain protein contents and winter wheat quality under normal N rate. 15 indexes of wheat quality were divided into 3 priciple components. The variance proportion of the first component was 60.22% and it also contained the most data information (e.g. wet gluten).With the the tested indices from high to low, the 18 fertilization treatments were classified to 4 clusters: no fertilizer treatment; conventional cattle and double cattle manure treatments; conventional chicken manure, pig manure, and chemical fertilizer treatments, combined under conventional rates; double chemical fertilizer, chicken manure, and pig manure treatments.

Conclusions Under conventional N rate, chicken or pig manure can be applied alone or combined with 25% of urea, cattle manure have to be combined with large proportions of urea. Overuse of urea or manures should not be recommonded for good winter wheat quality.