الفهرس 
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Abstract
This study was conducted during three successive seasons of 2008, 2009 and 2010 on Balady mandarin cultivar. The selected trees were uniform in vigour, 40 years old budded on sour orange rootstock. They grown in the Experimental Orchard of Faculty of Agriculture, Assiut University, Egypt, where the soil is clay and well drained. This study aimed to throw light on the beneficial effects of slow release and organic-N and K fertilizers as well as foliar spray of citrine (citric acid plus chelated Zn, Fe and Mn each 2%) on growth, nutritional status and fruiting of Balady mandarin trees. In addition, the target was planned for producing organic Balady mandarin fruits depending on reducing the application of fast mineral release fertilizers, as well as, reducing the environmental pollution which could be occurred by excess of chemical fertilizers use and industrial wastes.
This experiment included three factors (A, B and C). The first factor (A) which occupied the main plots comprised from the following two citrine, as antioxidants and micro nutrient complex treatments:
A1- Spraying citrine (citric acid plus chelated Zn, Fe and Mn each at 2%) at 0.5% twice at pre-flowering and fruit seting.
A2- Control (water spraying) and Triton B as wetting agent was added.
whereas, the second factor (B) involved three treatments from fast, organic and sprays liquid potassium fertilizer, as following:
B1- Potassium sulphate (48% K2O) 1000 g/tree as soil dressing in two equal batches on the first week of March and August.
B2- Spraying Vinasse (2.02% K2O) at 10%.
B3- Spraying Potassien (30% K2O) at 0.7%.
The third factor (C) comprised three treatments from fast, slow release and organic nitrogen fertilizers, as following:
C1- Application of the recommended rate (R.R.) of N (1000 g N/tree completely via fast mineral release source 3 kg ammonium nitrate 33.5% N)
C2- Application of 60% of (R.R) via slow release N fertilizer (3 kg Per/ka, (CaCN2) 19.8% N).
C3- Application of 40% of (R.R) via organic N fertilizer (135 kg F.Y.M., 0.3% N) + 20% via mineral via mineral (600 g ammonium nitrate 33% N)
Therefore, the experiment involved 18 treatments (2x3x3). Each treatment was replicated four times, one tree per each. Citrine was applied two times. Potassium sulphate was added at two equal batches and applied on the first week of March and August. Both vinasse and potassien were applied three times on mid of March, June and August, where solutions sprays were done till runoff (10 L/tree)
The organic N fertilizer (farmyard manure 0.3% N) was added once at the first week of January. slow release N fertilizer was added once at spring growth cycle started at (the first week of March). Ammonium nitrate as a fast release N fertilizer was splitted into three equal batches and added on the first week of March, May and August. Other horticulture practices were carried out as usual.
The treatment were set up as a randomized complete block design in split split plot arrangement with four replications and one tree for each. The following parameters were measured during the three studied seasons:
1- Some vegetative growth characters.
2- Leaf N, P and K contents.
3- Yield and its components.
4- Some physical and chemical fruit properties.
The data obtained during the three studied seasons could be summarized under the following main items:
1- Vegetative growth characters.
- Citrine spraying, as micronutrients, significantly increased the shoot growth and leaf parameters i.e. shoot length, thickness and its laterals number and total leaf surface area compared to unsprayed one.
- Vinasse spraying as source of potassium significantly increased the growth and leaf traits compared to fertilize by potassium sulphate (check treatment). Contrarly, potassien spray significantly deceased these shoot growth and leaf traits as compared to check treatment.
- In addition, all potassium fertilization sources in presence of citrine spraying significantly increased the shoot growth and leaves number and their area compared to untreated one.
- Using vinasse on the citrine treated trees gave the highest growth traits values, whereas potassien spraying on untreated trees recorded the least one.
Therefore, it could be concluded that foliar application either citrine or vinasse singly or incombination were effective in shoot growth and the number and area of leaves, such effect gave a pronounced improve in the vigour trees and its leaf surface expansion.
- Fertilizing by 60% of recommended dose of nitrogen (RDN) via 40% organic plus 20% mineral-N (two fertilization form) significantly increased shoot length and thickness and its number and total leaf surface area compared to using 100% RDN via fast mineral source only (check treatment). No significantly effect due to fertilization by 60% of RDN via slow release-N form compared with check treatment.
- The maximum shoot growth and leaf traits were detected in trees that fertilized with 60% of RDN via two fertilization form.
Moreover, all combinations of citrine spraying, vinasse spraying and nitrogen fertilization sources were significantly increased shoot growth and number and area of leaves. All combinations with either slow release or organic plus fast release-N (two fertilization form) gave the highest values of shoot growth and leaf traits compared to other combinations.
Therefore, it could be concluded that using 60% of RDN either 40% organic plus 20% mineral or slow release-N besides vinasse and citrine spraying would achieve a beneficial improvement of the tree growth and vigour.
In addition, it reduces the need for mineral fertilizers and decreases the cost of production as well as environmental pollution problems.
2 – Percentage of N, P and K in leaves:
- Nitrogen, phosphorus and potassium were significantly increased by citrine spraying comparison with unsprayed one (control).
- Using vinasse as foliage spray at 12% of recommended dose of potassium (RDK) significantly increased the percentage of N, P and K in the leaf compared to fertilize with potassium sulphate (check treatment).
- whereas, potassien spray at same concentration had unsignificant increase in N%, significantly increased in P% and significantly decreased in K% in leaves than check treatment.
- As interaction, all combinations of citrine spraying significantly increased the N, P and K% in leaves as compared to other fertilization treatments. The maximum percentage of N, P and K was recorded in leaves of citrine treated trees followed by vinasse spray.
- The least of leaf N and P% were recorded when trees not citrine sprayed and fertilized with potassium sulphate (check treatment), whereas the least K% found in leaves that untreated citrine and potassien spraying.
Therefore, using citrine as chelate micronutrient either only or combined with vinasse spraying as potassium source was very effective in improving the nutritional status of Balady mandarin trees.
Moreover, using micronutrients spraying accompanied with vinasse amending surpassed than either micronutrients or vinasse spraying alone.
- Fertilizing of RDN via 40% organic plus 20% fast release (two form) significantly increased the N, P and K% in leaves compared to using totally of RDN via fast release-N.
- No significant differences in N and K% in leaves due to fertilize with either 60% via slow release-N or 100% of RDN via fast release-N.
- All combinations of citrine (micronutrients) spraying, vinasse spraying and nitrogen fertilization sources significantly increased the N, P and K% in leaves. All combinations with 40% organic-N plus 10% mineral (two form) gave the highest percentage of N, P and K in leaves compared to other combinations.
Therefore, it could be concluded that fertilization by the two form of nitrogen and vinasse spraying along micronutrients spraying would achieve a beneficial improvement to vigour and nutritional status of trees. In additional, it reduced the need for mineral fertilizers and environmental pollution problems.
3 – Yield and its components:
- Fruit retention and number of fruits per tree were significantly increased due to using citrine compared with the untreated one. Hence, the maximum yield/tree were recorded on the trees that sprayed with citrine than unsprayed one.
- Using vinasse spray significantly increased the yield components compared to fertilize with potassium sulphae (check treatment). Meanwhile, potassien spray failed to show any significant differences on fruit retention, but significantly decreased the fruits number and yield/tree compared to check treatment.
All combinations of citrine spray significantly increased the yield components compared to other combinations. Vinasse spraying on the citrine treated trees gave the highest fruit retention, fruits number and yield/tree. However, the lowest these readings were recorded on untreated citrine trees that fertilized with potassien spraying.
- Thus, it could be concluded that citrine spraying plus using vinasse as organic-K would achieve a beneficial improvement of vigour, nutritional status and productivity of Balady mandarin trees.
- The trees fertilized with either slow release-N or two fertilization forms significantly increased the fruit retention, fruits number and yield/tree compared to application of N as 100% via fast mineral-N. The maximum values were recorded in trees fertilized with 60% of RND via 40% organic plus 20% fast release-N (C3). On other hand, application of N as 100% via fast mineral (C1) gave the minimum values of yield components.
- All combinations of micronutrients spraying, vinasse spraying and nitrogen fertilization sources (C) were significantly increased the fruit retention, fruits number and yield (kg)/tree. All combinations with 40% organic plus 20% fast release-N gave the highest fruit retention, fruits number and yield/tree compared other combinations. The highest values of fruit retention and fruits number, as well as, the heaviest yield were found on the trees that fertilized with two form of nitrogen p;lus vinasse and citrine spraying.
- Therefore, it could be concluded that slow release-N fertilizers, as well as the two form of fertilization along organic-K sources (vinasse) plus micronutrients spraying were a good modern method to increase the yield. In addition for using to organic farming production since they improved the soil structure and fertility of the soil. Such method reduce the cost of production as well as environmental pollution problems which could be occurred by excess of fast release mineral fertilizers and industrial wastes.
4 – Fruit properties:
4.1- Physical fruit properties:
- Using citrine as micronutrients spraying caused a better effect in increasing the weight and size of fruits and percentage of pulp and its size, as well as their juice volume comparing with untreated ones.
- Vinasse spraying significantly increased in these fruit traits compared to fertilize by potassium sulphate (check treatment). Contrarily potassien spraying significantly decreased these fruit traits compared to check treatment.
- Hence, it could be mentioned that using vinasse foliage as an alternative natural source of fast slow potassium (K2SO4) induce an increase in weight and size of fruit and consequently caused an increase pulp percentage and juice volume compared to check treatment (K2SO4).
- In general, most combinations of micronutrients spraying significantly increased the physical fruit properties compared to check treatment. Moreover, all combined micronutrients spraying with vinasse spraying significantly increased these fruit traits compared to other combinations.
- The heaviest and biggest fruits that had highest pulp percentage and juice content were found on the trees that sprayed by micronutrients and vinasse, followed by sprayed micronutrients along potassium sulphate. Contrarily, the lightest and smallest fruits had least pulp percentage and juice content were recorded on the trees that unmicronutrients applied along potassien spraying. whereas, the intermated for these fruit traits were recorded on check treatment.
- So, it can be concluded that micronutrients spraying accompanied with vinasse spraying as organic-K was more effective in improving the physical fruit properties compared to use either micronutrients or vinasse application only.
- Fertilized with 60% out of RDN via slow release-N or two form (40% organic plus 20% mineral, caused better effect in increasing the weight and size of fruit as well as pulp percentage, pulp size % and juice volume as compared to 100% RDN via fast mineral-N form.
- It could be mentioned that fertilization whatever, slow release-N at 60% or with 60% of two form were more pronounced than fertilization by 100% RDN via fast mineral-N.
Moreover, all combinations, especially with organic plus fast mineral-N was very effective in increasing the weight and size of fruit as well as percentage of pulp and pulp size % and juice content. All combinations of micronutrients and vinasse along organic plus mineral-N significantly increased the physical fruit properties compared to other combinations during the three studied seasons. The best physical fruit properties were detected on the trees that treated by 60% of RDN via two fertilization form plus vinasse and citrine spraying.
On the other hand, the least values of physical fruit traits were recorded on the trees which unmiconutrients applied and fertilized with mineral-N and potassien sprayed.
So, it can be concluded that either slow release or organic plus fast release mineral-N singly or in accompanied vinasse as organic-K fertilizer plus micronutrients spraying was more effective in improving the physical properties of the Balady mandarin fruits.
4.2- Chemical constituents juice:
Citrine spraying (as micronutrients) was non-significantly improved the soluble solids and sugar contents, whereas V.C. was significantly increased by application of citrine spraying compared with untreated one.
Using vinasse spraying improved the chemical constituents of fruits juice compared to fertilization by potassium sulphate (check treatment). whereas, potassien sprays significantly decreased the vitamin C contents and had insignificant effect on other chemical fruit properties compared to check treatments. Therefore, the highest fruit chemical properties were obtained when vinasse spraying compared to fertilization by potassium via fast release source or potassien spraying.
All combinations of micronutrients spraying along with potassium sources improved the fruit chemical quality as compared to check treatments. The highest values and best fruit chemical properties were found on the micronutrient sprayed trees that were fertilized with vinasse as organic-K fertilizer. On contrary, the least fruit property values were recorded on fruits from untreated micronutrients and fertilized with potassien sulphate or potassien sprayed.
Fertilization with 60% of RND via either slow release-N or 40% organic plus 20% fast release-N were improved the fruit chemical properties in terms of increasing total soluble solids, TSS/acid ratio as well as, sugar and V.C. contents and decreasing the total acidity compared to fertilize with 100% via fat release-N only (C1). No significant differences were found among fertilization either C2 or C3.
All combinations, especially with organic plus fast release-N (C3) or slow release-N (C2) were effective in improving fruit chemical properties. The highest these chemical properties were detected on trees that amended by A1B2C3. whereas, the least fruit chemical properties was recorded on trees that check treatment (A2B1C1). Theremore, all combinations either organic plus fast release or slow release-N was more effective in improving the fruit chemical quality compared all combinations of fast release-N.
Therefore, it can be concluded that fertilizing with 60% of recommended nitrogen dose (60% of RDN) whatever, two forms (40% organic plus 20% mineral-N) or slow release-N accompanied with vinasse spraying as organic-K along micronutrients spraying significantly improved the fruit properties and hastened the fruit maturation.
Conclusion
On the light of the previous results, it could be concluded that fertilization with either 60% of recommended nitrogen doses (RND) at two forms (40% organic plus 20 mineral-N) or slow release accompanied with vinasse spraying as a organic-K along citrine spraying as micronutrients to enhancing growth and nutritional status of Balady mandarin trees. In addition, they increased the yield and fruit quality. Moreover, they minimized the production cost and environments pollution which could be occurred by excess of chemical fertilizers used and excess of industrial wastes (vinasse).
These advantage will eventually enable growers to obtain high yield with good fruit quality. Furthermore, using slow release and organic forms of nitrogen and potassium enhance and preserve the soil fertility, as well as reduce the added fertilizer requirement amount, thus, the growers enable to produce organic mandarins.