Mikhael, G.B.Y. and Manal A. Aziz( 2016). Effect of replacing mineral nitrogen by organic Manures under different irrigation regimes on: A. Vegetative growth and nutritional status of “anna” Apple treesJ. Plant Production, Mansoura Univ., Vol. 7 (2): 203 - 216, 2016
Abstract: This investigation was carried out during three consecutive seasons of 2011, 2012 and 2013 to study the effect of irrigation regime, organic fertilization treatments and their interaction on some soil chemical and physical properties, vegetative growth and nutritional status of “Anna” apple trees budded on Malus root stock grown on clay soil at Tanta district, El-Gharbia Governorate. Results were only taken in 2012 and 2013 seasons. In this respect, three irrigation regimes at 70, 50 and 30% of available soil water (I1, I2 and I3) were used and cattle or chicken organic manures was applied at 0, 50, 75 and 100% combined with mineral N at 100%, 50%, 25% and 0% of the recommended dose of 400 g/tree/year in seven fertilization treatments (F1-F7).
The obtained results indicated that, soil physical and chemical properties except for pH and EC were significantly influenced by the tested organic fertilization and irrigation treatments in both seasons. The best results in increasing the percentage of organic matter and organic carbon, total porosity, aggregation parameters and reducing soil bulk density were obtained by increasing the application rate of organic manures up to 100% and using moderate irrigation rate at 50% AW (I2) compared to high (I1) or deficit (I3) irrigation one. Data of both seasons cleared that, shoot and leaf growth parameters, trunk cross section area-increase as well as average number and fresh weight of fibrous roots were significantly increased with increasing irrigation rate up to 50, 70% AW.
However, fertilization of 50% cattle or chicken manure + 50% mineral fertilizer (F2 or F5) resulted in the highest significant values of these vegetative growth parameters. The application of (I1 x F2), (I1 x F5), (I2 x F2) and/or (I2 x F5) considered to be the
best combination treatments for enhancing vegetative growth of “Anna” apple trees.
Obtained data revealed that application of cattle or chicken organic manure alone (F4 & F7) significantly increased leaf macro and micro nutrients as well as total chlorophyll contents, but significantly reduced free proline content. Moreover, fertilizing with chicken manure alone surpass of cattle manure alone in enhancing leaf mineral content. On the other hand, reducing irrigation rate up to 30% AW led to a significant reduction in leaf macro and micro-nutrients and total chlorophyll content, while, leaf free proline content was significantly increased in both seasons of study. The maximum values of N, P, K, Ca, Mg, Fe, Mn, Zn and total chlorophyll content were produced by (I1 x F7), (I1 x F4) and/or (I2 x F7) combination treatments without significant difference among them, while the minimum values recorded with (I3 x F1) treatment in both seasons.
Thus, this study recommended “Anna” apple growers to apply 50% cattle or chicken manure + 50% mineral N fertilizer under moderate irrigation regime in (I2 x F2) or (I2 x F5) which considered to be the best combination treatments for improving the most of soil physical and chemical properties, saving irrigation water with 11.73% and keeping soil moisture content which enhanced top and root system growth and leaf mineral and chlorophyll contents under clay soil conditions. By this treatment organic manures can reduce the need for about 50% of N mineral fertilizers, minimizing both production cost and environmental pollution which could be occurred by excess of chemical fertilizer.
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