الفهرس 
INTRODUCTION
Effect of fertilization applying on growth, nutrient status and fruitingOnly 14 pages are availabe for public view
 |  | from | 132 |  |  |
| | | from | 132 | | |
Abstract
The present study was carried out during two successive seasons of 2015 and 2016 on Thomson Seedless grapevines. The vines were 16 years old, spaced at 2x2.5 m apart and grown in experimental vineyard of the Faculty of Agriculture, Assiut University, Egypt, where the soil is clay. The chosen vines were received the usual agriculture practices that are used in the vineyard including P and K fertilization, irrigation, hoeing and pest control. The vines were trained according to the head training system and pruned during the second week of January.
Sixty healthy vines, with no visual nutrient deficiency symptoms and at almost uniform in their vigor were chosen. The treatments set up in completely randomized block design (CRBD) in a split-plot arrangement with three replicate, where factor A is an antioxidant and factor B is the fertilization treatments.
The first factor (A) involved four antioxidants spraying as follows:
A1- Control (sprayed with distilled water).
A2- Ascorbic acid at 500 ppm sprayed.
A3- Citric acid at 500 ppm sprayed.
A4- Selenium at 250 ppm sprayed.
The second factor (B) involved five treatments of nitrogen fertilization as follows:
B1- Application of 100% mineral-N (control).
B2- Application of 75% mineral-N plus 25% bio-form (12.5% nitrobin + 12.5% EM).
B3- Application of 50% mineral-N plus 50% bio-form (25% nitrobin + 25% EM).
B4- Application of 50% mineral-N plus 50% bio-form (12.5% nitrobin + 37.5% EM).
B5- Application of 50% mineral-N plus 50% bio-form (37.5% nitrobin + 12.5% EM).
Ammonium nitrate (33.5%) as mineral-N source was applied at three times, growth start, after berry set and 45 days later. Nitrobin and EM as bio-form was mixed with surface layer of the soil and added at first bloom and one month later. Solution of ascorbic acid, citric acid and selenium concentration were prepared with distilled water and then sprayed after berry set and month later.
The following parameters were determined to evaluate the effect of different treatments on growth, nutrient status and fruiting.
1- Some vegetative growth parameters.
2 – Leaf nutritional status.
3- Yield components.
4- Cluster and berry characteristic.
The results obtained during the course of manuscript will be demonstrated as follow:
1- Effect of certain antioxidant and bio-fertilizers on vegetative growth and leaf nutrient contents:
1.1- Shoot thickness and pruning wood weight:
Using bio-fertilization program at either 25 or 50% out of recommended dose of nitrogen (RDN) significantly increased the shoot thickness and annual pruning wood weight compared to using RDN at 100% mineral alone.
The maximum values of shoot thickness and pruning wood weight were recorded on the vines that fertilized with the required N as 50% mineral-N along 37.5% nitrobin plus 12.5% EM.
Ascorbic acid, citric acid and selenium spraying significantly increased the shoot thickness and weight of pruning wood compared to unsprayed ones (control). Using ascorbic acid or selenium gave the highest values of these traits compared to citric acid spraying. No significant differences were recoded due to spray any antioxidant compared to others.
The shoot thickness and pruning wood weight significantly responded to the interaction between the two studied factors. The highest values were obtained in vines that fertilized with 50% RDN via mineral-N plus 37.5% nibrobin and 12.5% EM combined ascorbic acid spraying (A2B5).
No significant differences due to fertilize with 50% mineral plus any 50% of bio-form along spray with ascorbic acid or selenium.
The combination effects significantly increased the shoot growth traits than increment due to individual effects of either fertilization treatments or antioxidants spraying.
1.2- Leaf characteristics:
Fertilizing with 75 or 50% of the recommended dose of nitrogen (RDN) as mineral-N along 25 or 50% as bio-form (Nitrobin or EM) significantly increased the number of leaves/ shoot, leaf area and total chlorophyll compared to use RDN via mineral-N source only.
The maximum values of number of leaves/shoot, leaf area and total chlorophyll were recorded on the vines that fertilized with 50% mineral-N plus 37.5 nitrobin and 12.5% EM. No significant differences were detected due to fertilize by 50% mineral-N along with any level of nitrobin or EM.
Number of leaves/shoot, leaf area and total chlorophyll significantly increased due to ascorbic acid, citric acid or selenium spraying compared to unsprayed ones. The highest values of these leaf traits due to ascorbic acid spraying compared to other antioxidants spraying. Using ascorbic acid failed to show any significant increase in these leaf traits compared to citric acid or selenium spraying.
Leaf characteristics significantly responded to the interaction between the two studied factors. The highest values were obtained in vines that fertilized with 50% RDN via mineral-N plus 37.5% nitrobin and 12.5% EM along ascorbic acid spraying (A2B5).
No significant differences due to use any 50% mineral 50% bio at any form combined ascorbic acid or selenium spraying.
1.3- Leaf nutritional status:
Application of required N through 75 or 50% of the recommended dose of nitrogen (RDN) as mineral-N along with using 25 to 50% as a bio-fertilizer significantly increased parentage of N, P and K in leaves compared to use RDN via mineral N fertilizer only.
The maximum values of leaf N, P and K percentage were recorded in the leaves of vines that fertilized with RDN via 50% mineral N and 37.5% nitrobin plus 12.5% EM (B5). On other hand, the lowest values were recorded in the leaves of trees that fertilized with 100% mineral-N (check treatments, B1).
Spraying either ascorbic acid, citric acid or selenium significantly increased the percentage of N, P and K in leaves compared to unsprayed ones (control). The highest values of these nutrients were detected on vines that sprayed with ascorbic acid compared to other treatments during two studied seasons. No significant differences were obtained due to citric acid spraying compared to selenium spraying.
All combination of fertilized by double forms (mineral and bio-form) with antioxidants spraying significantly increased percentage of N, P and K in leaves compared to check treatment. All combination of fertilization by 50% mineral plus 37.5 nitrobin and 12.5% EM form was most effective in the percentage of N, P and K in leaves.
The combination effects has more than effects due to individual application of either fertilization treatments or antioxidant spraying. Therefore, it could be concluded that fertilizing by triple form (mineral-N plus nitrobin and EM) along ascorbic or selenium spraying would achieve a beneficial improvement vegetative growth and nutritional status of Thompson Seedless grapevines. In addition, it reduced the need of mineral fertilizers and decreases the cost of production as well as environmental pollution problems.
2- Effect of certain antioxidant and bio-fertilizers on yield components:
Cluster number and yield (kg)/vine were significantly affected by various bio-fertilizers (Nitrobin & EM) program used. Using nitrogen fertilization as double form (mineral plus bio) significantly increased the clusters number and yield/vine compared to using recommended dose of nitrogen (RDN) via 100% mineral-N during the two studied seasons. Double form caused a remarkable promotion on clusters number and yield compared to use RDN via mineral-N source only.
The highest clusters number and yield/vine were detected due to fertilize by 50% mineral-N plus 37.5% nitrobin and 32.5% EM (B5).
The numbers of clusters and yield were significantly increased when antioxidant i.e. ascorbic acid, citric acid or selenium spraying compared to unsprayed ones. Spraying selenium gave the highest number of clusters and yield/vine compared to other treatments. No significant differences found due to selenium spraying compared to citric spraying.
The number of clusters and yield/vine significantly responded to the interaction between the two studied factors. The highest values were obtained in vines that fertilized with RDN via 50% mineral-N plus 37.5% nitrobin and 12.5% EM combined by selenium spraying (A4B5) compared to other combinations.
No significant differences due to use RDN via 50% mineral plus 50% of bio-form whatever (12.5, 25 or 37.5 nitrobin or (37.5, 25 or 12.5 EM) combined citric acid selenium spraying.
3- Effect of certain antioxidants and bio-fertilizers on cluster traits:
Using bio-form either 25 or 50% out of recommended dose of nitrogen (RDN) significantly increased the weight, length and berries number/cluster and significantly decreased the cluster compactness coefficient compared to use RDN at 100% mineral-N.
The maximum values of cluster weight, cluster length and berries number/cluster and least value of cluster compactness coefficient were recorded in the clusters of vines that fertilized with triple form (50% mineral-N plus 37.5% nitrobin and 12.5% EM, B5).
No significant differences on these studied cluster traits were found due to fertilize via 50% bio-form at any combination of nitrobin and EM whatever, 12.5 to 37.5%.
The cluster weights and its length significantly increased due to ascorbic acid (A2), citric acid (A3) and selenium (A4) spraying compared to unsprayed one (check treatment A1). The heaviest and length cluster was found on the vines that sprayed by selenium and ascorbic acid compared to other treatments, respectively.
The highest values of berries number per cluster and least values of cluster compactness coefficient were recorded on vines that sprayed with selenium and ascorbic acid, respectively.
On other hand, the least values of berries number and highest cluster compactness coefficient were found on vines that unsprayed (check treatment, A1). No significant differences on berries number/cluster was found due to selenium spraying compared to citric acid spraying. As well as no significant differences on cluster compactness coefficient was found due to ascorbic acid spraying compared to selenium spraying.
All combination of fertilization by double forms (mineral and bio-form) with antioxidants significantly improved the studied cluster traits compared to check treatment. All combination of fertilization by triple form (50% mineral-N, 37.5% nitrobin and 12.5% EM) was most effective compared to other combinations. Contrarly, the minimum values of cluster weight, cluster length, and maximum values of cluster compactness coefficient recorded on vines that fertilized with RDN via 100% mineral-N and unsprayed ones (A1B1). Other combination of double form (50% mineral plus 50% bio-form) combined with antioxidants spraying gave the intermediate values.
No significant differences were found among of combinations of fertilizing by RDN via 50% mineral plus 50% bio-form with selenium or citric acid spraying. As well as, all combinations of either selenium or citric acid spraying along with any fertilization treatments.
4- Effect of certain antioxidant and bio-fertilizers on some berry quality:
Using bio-fertilizers program at either 25 or 50% out of recommended dose of nitrogen (RDN) significantly increased the berry weight, berry size and total soluble solids (TSS), as well as reducing sugars and significantly decreased total acidity compared to using RDN at 100% mineral-N only (check treatment). The promotion on such berry characteristics was associated with increasing the applied level of bio-form from 25 to 50%.
The maximum values of these physiochemical properties except total acidity (least value) were recorded on the vines that fertilized with the RDN via 50% mineral-N along 37.5% nitrobin plus 12.5% EM. On other hand, the minimum values of then except total acidity (highest value) were recorded on the vines that fertilized with 100% mineral-N (check treatment B1). No significant differences were found due to fertilize by 50% mineral-N plus 50% bio-form at any combination from nitrobin and EM.
The berry dimension, TSS, reducing sugar contents and total acidity significantly decreased due to ascorbic acid, citric acid or selenium spraying compared to unsprayed ones. The highest values of berry weight, berry length and berry diameter were recorded due to selenium spraying compared to other treatments. On other hand, the least values of these berry traits detected on vines that unsprayed ones (check treatment A1). No significant differences were found due to spraying compared to citric acid or selenium spraying.
All combination of bio-form 50% plus 50% mineral as well as ascorbic and citric acid or selenium spraying significantly increased weight and dimension of berry as well as total soluble solids and reducing sugar and significantly reduced titratable acidity, compared to use mineral form and unsprayed ones (check treatment, A1B4).
The highest values of these berry quality parameters except total acidity (least) recorded on vines that received 50% mineral-N plus 37.5 nitrobin and 12.5% EM and combined with ascorbic acid (A2B5) or selenium spraying (A4B5). Whereas the minimum values of these traits except total acidity (highest) were detected on vines that fertilized with RDN via 100% mineral and unsprayed ones (A1B1).
Conclusion:
On the light of previous results, it could be concluded that fertilizing by 50% bio-form plus 50% mineral accompanied with ascorbic acid or selenium as a source of antioxidants fertilization enhancing growth and nutritional status of Thompson Seedless grapevines. In addition, they increased the yield and improved the cluster and berry traits. Moreover, they improved the soil fertility and minimized the production cost and the environments pollution which could be occurred by excess of chemical fertilizers used.