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The current investigation aimed to: 1) study the useful effects of using different phosphorous fertilizer sources on some faba bean genotypes and 2) determine the validity and usefulness of using alpha lattice design over randomized complete block design, RCBD, for increasing the precision of faba bean yield trials.
To investigate each one of the abovementioned research topics, two field experiments were separately carried out at Giza Agricultural Research Station, Giza Governorate, Egypt during the winter growing seasons of 2015/2016 and 2016/2017.
Accordingly, the present work can be classified into two parts of experimentation as follows:
Experiment I: The response of three faba bean cultivars to five phosphorous fertilizer forms,
Experiment II: The efficiency of alpha lattice design versus RCBD.
Experiment I. The response of faba bean cultivars to phosphorous fertilizer forms:
Such field trail was carried out to study the effects of five phosphorous fertilizer forms on growth and productivity of three faba bean cultivars being Sakha 3, nubaria 1 and Giza 843. The factorial treatments were laid out in randomized complete block design with three replicates. The fertilizer treatments contained mineral, natural and bio-phosphorous fertilizers as well as three combinations of them as follows:
6. Rock phosphate,
7. Super phosphate,
8. Phosphate dissolving bacteria (Bacillus megatherium),
9. Rock phosphate + (Bacillus megatherium),
10. Super phosphate + Bacillus megatherium).
Each of rock phosphate, 32 % P2O5 and super phosphate 15.5% P2O5 were applied during land preparation at a rate of 15.5 kg P2O5 fed−1 representing 6.5P kg fed−1. The seeds were inoculated by soaking in cell suspension of Bacillus megatherium (in the form of phosphorein as a commercial product) for 30 minutes before sowing. Sucrose solution 30% was added as an adhesive agent prior to inoculation.
The whole experimental plot size was 9.6 m2 containing 3 ridges (4.0 m length and 60 cm apart). Seeds of faba bean cultivars were sown on mid–November in both growing seasons (2–3 seeds per hill) with 15–cm distance on one side of the ridge.
Results of this experiment were illustrated on the following items:
1. P content in soil: It is shown that rock phosphate along with Bacillus megatherium and rock phosphate + B. megatherium recorded the highest values of available P in soil after harvest in 2nd season. However, Nubaria 1 and Sakha 3 possessed higher available P values than Giza 843 in 1st season. more available P remained in soil after harvest due to application of super phosphate x Nubaria 1 in the 1st season or Rock phosphate x Sakha 3 in the 2nd one.
2. Ca content in soil: Application of rock phosphate + B. megatherium in the 1st season as well as super phosphate + B. megatherium along with rock phosphate in the 2nd season recorded the minimum values of available Ca. Cultivation of Nubaria 1 genotype in the 1st season and Sakha 3 in the 2nd one showed the lowest amount of available Ca after harvesting compared to Giza 843 genotype. The most effective interaction for reducing Ca from soil was obtained by fertilizing Nubaria 1 by super phosphate in 1st season and Sakha 3 or Giza 843 fertilized with rock phosphate or super phosphate + B. megatherium in 2nd season.
3. Leaf chlorophyll content (SPAD reading): The maximum value of SPAD was recorded with B. megatherium treatment in both seasons. Plant leaves of Giza 843 genotype were greener than Sakha 3 or Nubaria 1 since they produced higher values of SPAD in both seasons. The most combinations for enhancing SPAD value were rock phosphate or (super phosphate + B. megatherium) x Giza 843 and B. megatherium x Sakha 3 in 2015/2016 and Giza 843 fertilized by B. megatherium in 2016/2017.
4. Plant height: In this regard, inoculation faba bean seeds with B. megatherium and application of rock phosphate in both seasons were the best treatments. The tallest plants of faba bean were obtained with Nubaria 1 in both seasons surpassing the other two genotypes in the first season only. Significant interaction between phosphorus fertilization treatments and faba bean genotypes was noticed in the first season only. Therein, Nubaria 1 and Sakha 3 plants fertilized with B. megatherium recorded the maximum plant height.
5. Branches number plant−1 All phosphorus fertilization treatments statistically leveled in branches number plant−1 except rock phosphate + B. megatherium treatment. Moreover, Sakha 3 and Nubaria 1 produced the highest values of branches number plant−1. The interaction revealed that fertilizing Sakha 3 by B. megatherium alone as well as Nubaria 1 by super phosphate + B. megatherium showed the highest increases.
6. Pods number plant−1: varietal differences had marked effect on pods number plant−1 since Nubaria 1 exceeded each of Sakha 3 and Giza 843 in both seasons. However, the fertilizer treatments of B. megatherium alone or in combination with super phosphate gave the highest pods number plant−1 in two seasons. Plots sown by Nubaria 1 and received B. megatherium, rock phosphate or rock phosphate + B. megatherium as well as that sown by Sakha 3 and fertilized by super phosphate + B. megatherium achieved the maximum values in the 1st season. However, the most effective combinations in 2nd season was B. megatherium x Giza 843 .
7. Pods weight plant−1: Genotypes Nubaria 1 along with Sakha 3 were the potent genotypes for producing maximum pods weight plant−1 in the 1st season. Fertilizing Nubaria 1 with B. megatherium (in both seasons) or rock phosphate (in the 1st season), Sakha 3 with super phosphate + B. megatherium (in the 1st season) as well as Giza 843 with B. megatherium or rock phosphate (in the 2nd season) were the most effective combinations for promoting pods weight plant−1.
8. Seeds number plant-1: the highest seeds number plant-1 were gained from plots fertilized by super phosphate + B. megatherium in both seasons. Superiority of Nubaria 1 genotype for producing higher values of seeds number plant−1 was more evident in both seasons. The interaction of super phosphate + B. megatherium x Nubaria 1 showed the highest increase in seeds number plant−1 in the two growing seasons.
9. Seed weight plant−1: Using of super phosphate + B. megatherium, B. megatherium and rock phosphate in 2015/2016 as well as B. megatherium and rock phosphate in 2016/2017 enhanced seed weight plant−1 surpassing the other ones. It is clear that Nubaria 1 gave the heaviest seed weight plant-1 in both seasons. Application of rock phosphate or B. megatherium or super phosphate + B. megatherium x Nubaria 1 achieved the maximum increments in seed weight plant−1 in the 1st season. While, B. megatherium x Nubaria 1 or Giza 843 were the potent interactions in the 2nd season.
10. Seeds number pod−1: Plots fertilized with B. megatherium + super phosphate or rock phosphate recorded the highest value of seeds number pod−1 in both seasons. Sakha 3 along with Nubaria 1 in 2015/2106 and Nubaria 1 in 2016/2017 possessed the maximum increases in seeds number pod−1. Combination of Nubaria 1 genotype and super phosphate + B. megatherium in the 1st season or rock phosphate + B. megatherium in the 2nd one recorded the highest seeds number pod−1.
11. Weight of 100 seeds: Rock phosphate alone, rock phosphate + B. megatherium and B. megatherium alone showed the maximum increases in 2016/2017. Nubaria 1 in the 2nd season as well as Nubaria 1 or Giza 843 in the first one recorded the highest weight of 100 seeds. in the 2nd season Except for super phosphate + B. megatherium (with Sakha 3) and super phosphate + B. megatherium, and super phosphate alone (with Giza 843), the other P application possessed the maximum weight of 100 seeds.
12. Seed yield: The beneficial effect of phosphorus fertilizer for enhancing seed yield appeared well with super phosphate + B. megatherium in both seasons. Moreover, such effective practice was statistically at par with each of B. megatherium and super phosphate applied alone in the 2nd season. Superiority of seed yield of Nubaria 1 genotype was more evident in 1st season while, both of Nubaria 1 and Sakha 3 were similar in producing seed yield in 2nd season. The obtained significant interaction proved that except for rock phosphate (in both seasons) and super phosphate (in the second one), Nubaria 1 genotype treated with other phosphorus fertilizers recorded the maximum seed yield. Also, Sakha 3 genotype treated with super phosphate + B. megatherium (in both seasons) or B. megatherium (in the second one) had well potentiality in this respect.
13. Pod yield: it is stated that super phosphate + B. megatherium treatment have the maximum value of pod yield surpassing the other phosphorus applications in 2015/2016. However, in 2016/2017 were super phosphate or B. megatherium in this regard. The potentiality to produce a higher pod yield resulted from Nubaria 1 in both seasons. Nubaria 1 genotype received any phosphorus form, except super phosphate (in both seasons) or B. megatherium (in the 1st season) as well as Sakha 3 genotype fertilized with super phosphate + B. megatherium (in the 1st season) or each of super phosphate, B. megatherium and rock phosphate + B. megatherium (in the 2nd season).
14. Biological yield: Using of each of rock phosphate + B. megatherium and super phosphate + B. megatherium was the effective practices in the 1st season recording the maximum biological yield. While, B. megatherium alone recorded the highest values in the 2nd season. Nubaria 1 alone in the 1st season as well as Nubaria 1 along with Sakha 3 in the 2nd one gave the highest values. In the 1st season, B. megatherium x Nubaria 1 along was the effective combinations for producing biological yield. Moreover, in 2016/2017, a lot of combinations among phosphorus fertilizers and faba bean genotypes increased biological
15. Hulling %: Results showed that all P applications significantly increased hulling % compared to rock phosphate in 1st season. Moreover, super phosphate + B. megatherium recorded the maximum hulling % in 2nd season. first season Nubaria 1 surpassed the other two genotypes in hulling %. Nubaria 1 fertilized with B. megatherium or super phosphate as well as Giza 843 fertilized with super phosphate + B. megatherium or rock phosphate + B. megatherium achieved the maximum enhancements in hulling %.
16. Harvest index %: It is revealed that super phosphate + B. megatherium treatment gave the maximum increase in harvest index surpassing in both seasons. Nubaria 1 genotype recorded the maximum value of harvest index in the 1st season only. Therein, fertilizing Nubaria 1 genotype with super phosphate alone or super phosphate + B. megatherium as well as Sakha 3 genotype with super phosphate + B. megatherium were the compatible interactions in the 1st season. In 2016/2017, fertilizing the three tested genotypes with super phosphate + B. megatherium, as well as Sakha 3 with B. megatherium and Giza 843 with super phosphate gave the highest values of harvest index.
17. Seed N content %: All P forms had similar impact on N seed content of faba bean in both seasons except rock phosphate + B. megatherium in the first season which gave lower value. The variation in N seed content among faba bean genotypes appeared in the 2nd season only. Herein, Nubaria 1 showed the maximum value. The interaction effect between P fertilizer and faba bean genotype on N seed content was significant in the 2nd season only. Except for Sakha 3 (with rock phosphate + B. megatherium or super phosphate + B. megatherium), Nubaria 1 (with B. megatherium) as well as Giza 843 (with rock phosphate or super phosphate), the other combinations achieved considerable increases of seed N
18. Seed P and K contents %: the present results clarified that P fertilizer forms and faba bean genotype and their interaction had no marked effects on P and K contents in faba bean seeds.
19. Seed protein content %: results showed that there were significant differences among phosphorus fertilizers in the 1st season only. Except rock phosphate + B. megatherium, all other P fertilizer forms enhanced the seed protein content. The effects of faba bean genotypes and their interaction with P fertilizer forms were significant in the 2nd season only. Nubaria 1 gave the maximum value compared to the other two genotypes. Giza 843 fertilized with B. megatherium or rock phosphate + B. megatherium or super phosphate + B. megatherium as well as Nubaria 1 fertilized with all P fertilizer forms except B. megatherium achieved the maximum enhancements of seed protein content %.
P recovery efficiency
Data revealed the significant effect of P applications on P recovery efficiency. The extreme value was obviously obtained with B. megaterium treatment. Nubaria–1 recorded the maximum value of P recovery efficiency surpassing the other two cultivars. The highest P recovery efficiency was achieved with Nubaria–1 inoculated by B. megaterium alone transcending the other interactions in this respect.
Conclusion and Recommendations:-
1. It could be deduced that P application by selecting the appropriate form, i.e. super phosphate+B. megaterium and planting the suitable cultivar via Nubaria–1 as agronomic inputs to achieve maximum crop returns and secure high short–term recovery of applied P should be taken in mind.
2. Thus, the application of P should aim to match as much as possible the requirement of each faba bean cultivar with the available P in soil for minimizing the excess of P in soil useless to the plant and avoiding the ecosystem pollution.
3. Also, P level in the soil could be manipulated together with the genetic diversity of the crop as a breeding tool for faba bean cultivars development through improving P uptake and/or utilization efficiency. At the same time, managing scarce P resources to avoid increasing soil P levels in some field areas above critical levels should not be neglected.
Experiment II: The efficiency of alpha lattice design and trend analysis versus RCBD.
Such trail aimed to compare the analysis of variances for yield potential of 20 faba bean genotypes using RCBD, alpha lattice design and trend analysis. Faba bean genotypes were laid out in an alpha lattice design with three replications. Each replication was divided into four incomplete blocks with five plots each. The layout of the field experiment was a grid of 12 rows and 5 columns in the two growing seasons. Each plot consisted of three ridges of four m long and 0.6 m apart with two seeds/hill, 20 cm apart. At maturity, each plot were harvested to determine the seed yield in kilograms per plot and converted to the unit of ardab fed-1.
The obtained results of this experiment can be summarized as follow:-
1- Fitting RCBD model, the results showed that the genotype source of variation was significant (P < 0.05) only in the 1st season. Alpha lattice design recorded highly significant (P < 0.01) F-test for genotype effect in the two growing seasons while the varietal effect of trend analysis reflected significant and highly significant in the 1st and 2nd seasons, respectively.
2- The Alpha lattice design is statistically preferred over RCBD because it recorded the highest values of relative efficiency % and power function, along with statistically acceptable low values of coefficient of variation % and P-value in both seasons.
3- Results of trend analysis exhibited somewhat more precision compared to RCBD in both seasons but its efficiency was lower than alpha lattice analysis.
4- Accordingly, it could be concluded that the model depending on positional information about field plots might be considered a good tool to discover and overcome the spatial heterogeneity among the experimental plots, especially when the RCBD appeared ineffective.
5- Considering the three models of analysis simultaneously, results showed that genotypes number 6 and 8 produced the highest seed yields that ranged from 11.87 to 13.03 ard./fed. in the 1st growing season with no significant differences among them. In the 2nd season, genotypes number 5, 9 and 10 had the maximum seed yield that ranged from 12.57 to 13.99 ard./fed.
6- Results revealed positive and highly significant (P < 0.01) Spearman coefficients of correlation among the genotype means that obtained from the three models in both seasons.
7- Application of alpha lattice design or trend analysis does not require major inputs or a complex field layout; therefore, it is proposed to use any of them in large variety trials