الفهرس 
Planting methodOnly 14 pages are availabe for public view
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Abstract
Two series of experiments were carried out at the Experimental Farm, Faculty of Agriculture, Kafr El-Sheikh, Tanta University during 1991 and 1992 seasons, to study the effect of some agricultural treatments on rice yield and qua3.it.y which will be summarized as follow: Part I, Land Levelling Methods and Nitrogen Rates: Two field experjment.~ were carrj.ed out to study the effect of land levelling methods and N rates on growth, yield and grain quality of rice. The experimental design was a strip-split plot design wi.th four replications, where the three levelling methods (1. Dry levelling, 2. Dry levelling + puddling once, 3. Heavy puddling) and the three rice cultivars (IR 28; Giza 175 and Giza 176) were assigned to the main plots and the three N-rates (50, 65 and 80 kg N/fad in urea form). to t,he sub-plot. The sowing date was May 20 and the transplanting was done 30 days after sowing in both seasons. Nitrogen was applied in two equal split doses: One half after 5 days and the second one after 30 days from transplanting. Growth analysis and attributes parameters were studied at three srlrcessj~~ger owth ages ( i . e. 70, 84, 98 days after sowing). Grain yield and its components and grajn quality were determined at mature stage. The results obtained a r e summarized a s follow: I. Growth Analysis and A t t r i b u t e s : I . A . Growth Analysis: I.A.1. Dry m a t t e r accumulation: In both s e a s o n s , I R 28 o u t y i e l d e d s i g n i f i c a n t l y Giza 175 and Giza 176 a t a l l growth ages. Also, dry l e v e l l i n g t r e a t m e n t i n c r e a s e d signifjcantly dry weight/hill a s compared with t h e o t h e r s . Concerning N-rates, r e s u l t s showed a l i n e a r s i g n i f i - c a n t jncrease i n dry m a t t e r accumulation at a l l growth ages due t o t h e i n c r e a s e of N-rates up t o 80 kg N/fad. T . A . 2 . Plant h e i g h t ( c m ) : The d i f f e r e n c e s among v a r i e t i e s w e r e s i g n i f i c a n t where, 1R 28 gave t h e s h o r t e s t p l a n t s and Giza 176 gave t h e t a l l e s t ones. Land l e v e l l i n g methods has s i g n i f i c a n t e f f e c t on t h i s t r a i t only at h a r v e s t t i m e while dry l e v e l l i n g gave t h e t a l l e s t p l a n t s as compared with t h e o t h e r s . Also, a l i n e a r i n c r e a s e s between N-rates and p l a n t h e i g h t were found at a l l growth ages in b o t h s e a s o n s . T.B. Growth A t t r i b u t e s : I.B.1. Leaf area/hill: The d i f f e r e n c e s among varjeties in l e a f a r e a w e r e s i g n i f i c a n t at a l l growth a g e s , where Giza 176 gave t h e hj g h e s t v a l u e s . Also, dry l e v e l l i n g t r e a t m e n t gave t h e h i g h e s t l e a f a r e a followed by dry l e v e l l i n g + puddling once and heavy puddling t r e a t m e n t . The e f f e c t of N r a t e s on l e a f a r e a was signi ficartt at a1 1 growth ages i n both seasons. T.B.2. Leaf area index: The t r e n d of r e s u l t s f o r t h e e f f e c t of v a r i e t y , land levelljng methods, and N-rates on LA1 are s i m i l a r t o t h o s e of LA . I .B. 3 . Crop growth rate: (CGR = g/m2/week) The d i f f e r e n c e s between v a r i e t i e s i n CGR were s i g n i f i c a n t i n 1992 o n l y . In g e n e r a l , I R 28 gave t h e h i g h e s t v a l u e s followed by Giza 175 where Giza 176 gave t h e l o w e s t o n e s . Also, dry 1 e v e l l j ng t r e a t m e n t gave t h e h i g h e s t CGR v a l u e s f o l 1 owed by dry 3 eve1 3 i ng + puddling once and heavy puddl ing . Jn general CGR v a l u e s tended t o i n c r e a s e s i g n i f i c a n t l y as Nr a t e i n c r e a s e d . T . R . 4 . R e l a t i v e c r o p growth rate: (R.G.R = g/g/week) The d i f f e r e n c e s among v a r i e t i e s i n R . G . R . w e r e sjgnificant where, Giza 176 gave t h e h i g h e s t v a l u e s followed by G i z a 175 and TR.28 gave t h e l o w e s t o n e s . In g e n e r a l , heavy puddling gave t h e hjghest R.G.R. followed by dry l e v e l l i n g + puddling once and dry l e v e l l i n g . Also, i n c r e a s i n g N - f e r t i l i z e r r a t e up t o 65 kg/fad i n c r e a s e d R.G.R. v a l u e s s i g n i f i c a n t l y only i n 1992. I.B.5. Heading date: In both s e a s o n s , I R 28 w a s t h e e a r l i e s t followed by Gj za 175 where Gj za 176 w a s t h e latest one. However, land l e v e l 1 i n g t r e a t m e n t s fai led t o e x e r t any s i g n i f i c a n t d i f f e r - ences i n heading d a t e . Rut, i n c r e a s i n g N-rate from 50 up to 80 kg/fad. delayed heading time by about 6.5 days.