الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
To study the effect of farmyard manure rates (0, 10 and 20m3 fed-1), silicate bacteria (without and with inoculation) and potassium fertilizer levels (0, 50 and 100 K kg fed-1) on status of soil-N and K nutrients at different growth stages of potato plants cultivated in alluvial soil, a field experiment was laid out at private farm (Kafr EL-Arab, Talkha, Dakahlia Governorate, Egypt during winter 2005/2006 season. The obtained results could be summarized as follows:
- Except for fresh and dry yields, N content of tops (kg fed-1) and P% in potato organs (tops + tubers), the differences among means of starch content (%), specific gravity (g cm-3), N, P, K% and its contents (kg fed-1) of top and tuber by inoculation of silicate bacteria (Bacillus circulans) reached at the level of significance (p=0.05) during the growing successive season.
- Statistical analysis indicates that fresh and dry yield of potato organs (top + tubers), tuber quality i. e. starch % and Sp. gravity (g cm-3) and N, P, K% and its contents (kg fed-1) of tops and tubers except for P% in tubers and K% in tops + tubers were significantly increased with increasing of farmyard manure rates from 0 up to 10 and 20 m3 fed-1, respectively.
- Data indicate that additional rates of K-fertilizer significantly increased fresh top and tuber yields (ton fed-1), starch %, specific gravity (g cm-3), N, K% and its content (kg fed-1) of tops and tubers during the growth season. Meanwhile, dry top and tuber yields (ton fed-1), P% and its content (kg fed-1) of potato plants materials insignificantly increased with increasing K fertilizer rates. Generally, the highest means were recorded with the potassium rate of 100 K kg fed-1 (K2).
- The multiple linear regression shows that there is a highly significant correlation (P = 0.01) among potato tuber yield (y) and starch %, top yield, top N and K and tuber P contents except for N tuber and top P and tuber K contents (r2 = 94.7%).
- Data clear that application of farmyard manure (FYM) had a positive effect on soil-N forms contents i. e. NO-3, NH+4 and total available N (TAN) at 70, 90 and 110 DAP, respectively.
- Also, data reveal that the contents of soil-NO-3,NH+4 and total available N(mg kg soil-1) slightly affected due to inoculation of silicate bacteria as compared to the control, respectively. Moreover, application of K fertilizer had a slight effect on contents of soil-NO-3 and total available N (mg kg soil-1). Meanwhile, there is a descent trend on soil-NH+4 content due to increasing levels of potassium fertilizer at 70, 90 and 110 DAP during 2005/2006 season.
- Statistical analysis reveal that, the addition of farmyard manure0 up 10 to 20 m3 fed-1, silicate bacteria (Bacillus circulans) and K-fertilizer from 0 up to 50 and 100 K kg fed-1 caused vigorously enhancing in available soil-K content (mg kg soil-1) at different growth stages of potato crop at 70, 90 and 110 DAP.
- Multiple linear regression from the following equation revealed that N-forms and available soil-K had a pronounced effect on predicting the tuber yield (ton fed-1) of potato plants (r2 = 88.5%).