| 4-year-old Summer Black and Red Globe grape cultivated under rain-shelter in Pengshan County of Sichuan Province were selected as materials in present study to investigate the effect of topdressing using chicken manure (fermented or dried) combined with chemical fertilizer (urea or compound fertilizer or potassium sulfate). In the control group (CK), conventional fertilization (urea in sprouting period, and compound fertilizer in fruit enlargement period) were conducted. The portable photosynthesis system (Li-6400xt) was used to determine the leaf gas exchange parameters at different phenophases, Diurnal variation of leaf gas exchange parameters and the response characteristics of Pn to environmental factors were also evaluated in fruit enlargement period. The results were as follows:1. The photosynthetic capacity of Summer Black and Red Globe were affected by the combined application of chicken manure and chemical fertilizers in flowering period, fruit enlargement period, fruit turning period and fruit ripening period. The photosynthetic capacity presented a general up-trend with increasing amount of fertilizer for both grapes.(1)1.00kg dried chicken manure,0.20kg compound fertilizer and0.10kg urea per plant in germination period, and1.00kg dried chicken manure,0.05kg urea and0.20kg potassium sulfate per plant in fruit enlargement period was the best fertilizing combination for Summer Black. Almost all the combined fertilization using chicken manure and chemical fertilizer promoted the Pn of this grape by0.83～14.26%in flowering period, except that a few combinations were slightly inhibitory. The Pn in all combined fertilization treatments were significantly higher than that in CK in fruit enlargement period. Compared with that in CK, the ascentional amplitude of Pn in combined fertilization treatments ranged from3.90%to18.14%,3.94%to31.00%,19.37%to59.6%in fruit enlargement period, fruit turning period and fruit ripening period, respectively. Generally, Gs, Tr and WUE were all enhanced, while Ci was suppressed applied with chicken manure and chemical fertilizers simultaneously.(2)1.25kg dried chicken manure,0.20kg compound fertilizer and0.10kg urea per plant in germination period, and1.25kg dried chicken manure,0.05kg urea,0.20kg potassium sulfate per plant in fruit enlargement period was the best fertilizing combination for Red Globe. All but a few combined fertilization treatments were stimulative to the Pn of this grape in flowering period, and in fruit enlargement period all combined fertilization treatments showed stimulative effects. An increase of0.70%～13.04%., an increase of4.77%～17.78%, and an increase of13.80%～39.45% were observed in Pn treated with combined fertilizers in flowering period, fruit turning period and fruit ripening period, respectively. Similar to those in Summer Black, G5, Tr and WUE were all enhanced, while Ci was suppressed in Red Globe applied with combined fertilizers.2. The photosynthetic capacity was enhanced in two grapes in fruit enlargement period when combined application of chicken manure and chemical fertilizers was implemented, but the diurnal variation of gas exchange parameters was not altered. In fruit enlargement period (late May and early June), the diurnal variation of Pn presented a bimodal curve in fair weather for both grapes. An obvious "midday depression" phenomenon appeared, and the second peak value was lower than the first peak value. The diurnal variation curves in treatments applied chicken manure and chemical fertilizers simultaneously were above that in CK for both grapes. The diurnal variation of Gs and WUE also presented bimodal curves, while a single-peak curve was observed in Tr, and a "W" curve was observed in Ci. During10:00～12:00, the Pn descended sharply accompanied with the fall of CI and Gs, and the rise of Ls. So the stomatal factor should be responsible for the "midday depression" at this time. During12:00～14:00, a sharp decrease was still seen in Pn and Gs, but Ci increased. This indicated that the non-stomatal factors, i.e., the limitation on the photosynthetic assimilation capacity led to the phenomenon of "midday depression" at this time.3. The Pn-PAR curve was quadratic either in treatments applied medium chicken manure (1.00kg) and medium chemical fertilizers (0.25kg compound fertilizer or0.05urea combined with0.20kg potissum sulfate) as well, or in CK in fruit enlargement period for both Summer Black and Red Globe. The AQY in each combined fertilizing treatment was higher than that in CK for both grapes, indicating that the light utilization efficiency of two grapes was enhanced by combined application of chicken manure and chemical fertilizers. Additionally, the ability of using low-light was improved, and the available light interval was expanded under combined fertilization, because both Lcp and Lsp increased. This was benefitial for two grapes to accumulate photosynthetic products. Compared with CK, an increase of25.8%-64.2%in Pnmax, and an increase of18.2%-51.5%in AQY were observed for Summer Black, while an increase of23.4%-53.2%in Pnmax, and an increase of12.5%-35%in AQY were observed for Red Globe.4. The-Pn-CO2curve was also quadratic either in combined fertilizing treatments with medium chicken manure and medium chemical fertilizers, or in CK in fruit enlargement period for both Summer Black and Red Globe. The CE, Pnmax, Csp, Rp and available range of CO2concentration in each combined fertilizing treatment were all higher than those in CK, but Ccp were lower than that in CK. Combined application of chicken manure and chemical fertilizers was potential to improve the CO2utilization efficiency of two grapes, especially to improve the ability to use low concentration of CO2, and additionally, to expand the available range of CO2concentration. After combined fertilization, the Pnmax was improved by13.6%～41.0%and11.9%-28.7%for Summer Black and Red Globe, respectively.5. The dried chicken manure was better than the fermented chicken manure in stimulating the photosynthetic capacity. In fruit enlargement period, combined application of urea and potassium sulfate was slightly better than the application of compound fertilizer alone when both the type and the amount of chicken manure were fixed. |
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