Effects of manure application on yield and quality of Red Globe grape and soil environment

Objectives This study was to quantify the effects of manure application on yield and quality of grape and on the soil environment, to provide theoretical basis for rational manuring in grape production.

Methods A 4-years field experiment was conducted in Huailai National Grape Demonstration Base in Zhangjiakou, Hebei Province. The tested grape was the 13-year-old Red Globe, and six treatments were designed as: conventional fertilization (CK), chemical fertilizer (NPK), manure 9 t/hm² (M), chemical fertilizer + manure 7.5 t/ham² (M1NPK), chemical fertilizer + manure 15 t/hm² (M2NPK), and chemical fertilizer + manure 45 t/hm² (M3NPK). The yield, quality and heavy metal contents in grape fruit were measured. The nitrate nitrogen, microbial biomass carbon and nitrogen, and heavy metal contents in soil were determined. The years for reaching the heavy metal limits in vineyard soil were estimated.

Results Compared with NPK treatment, M treatment significantly increased the grape yield, and the highest average yield of the four years was obtained in M2NPK treatment, which was 21503 kg/hm² and 14% higher than that in the CK. The fruit Vc content in M2NPK treatment was also the highest, which was averaged 14.25 mg/100 g and significantly higher than that of the CK during 2010–2013 (P < 0.001). There were no significant differences in 100-fruit-weight, pH value, soluble solids and titrable acid contents and solid acid ratio among the treatments. In the M2NPK treatment after fruit harvest, the accumulation of nitrate in 0–20 cm and 20–40 cm soil layers were decreased in M2NPK treatment, while the soil microbial biomass carbon and nitrogen contents were significantly higher than those in CK. After 4-years continuous manure application, the contents of Cr, Cd, As, Pb, Hg, Cu and Zn in both grape fruits and soils were lower than the upper limits, however, they showed a linear and quadratic increasing trend with the increase of the organic manure application rate. Thereafter the M3NPK treatment would be the fastest one to accumulate soil heavy metal beyond the limits of pollution.

Conclusions Application of 15 t/hm² of chicken manure combined with NPK fertilizers could produce high yield and good quality of grapes, low accumulation of nitrate nitrogen in surface and subsurface soil layers, and increase soil microbial carbon and nitrogen contents. The content of heavy metals in grape fruits and orchard soil is not beyond the limit in M2NPK treatment. Heavy application of manures will not produce further improvement in yield and quality of grapes, but lead to fast heavy metal accumulation in orchard soil under the tested experimental condition.