Abstract
Abstract Two field experiments were conducted in June, 1978, and April, 1979, at the Khartoum University Farm, Sudan, to study the effect of irrigation frequency, urea‐nitrogen, and gypsum on the yield of forage sorghum ( Sorghum vulgare L.) grown on a semi‐arid, salinesodic clay soil. Each experiment had four nitrogen levels: 0N, 1N, 2N, and 3N (1N = 43.8 kg N/ha) applied as urea; three irrigation frequencies: 7, 10, and 15 days; and zero or 11.9 tonnes/ha gypsum, each replicated thrice in a split‐split plot design. The seasonal quantity of water applied was the same for all frequencies of irrigation and was slightly higher than evaporation from a U.S. class A pan. The two seasons data consistently showed that dry matter yield of the first cuts of forage sorghum increased significantly with increase in N‐level, with decrease in irrigation interval, and with gypsum application. Decreased irrigation frequency had greater effect than 3N fertilization. The benefits from gypsum application were low (5%) at the 7‐day irrigation interval. Dry matter yields were increased from 1.84 to 6.12 tonnes/ha in 1978 and from 3.20 to 7.23 tonnes/ha in 1979, by irrigating every 7 days instead of 15 days, application of 3N and 11.9 tonnes/ha gypsum. Plant height and leaf area index increased with N fertilization, with gypsum and with reduction of irrigation interval from 15 to 7 days, whereas germination percentage was significantly increased by gypsum only. Dry matter yield significantly correlated (P = 0.01) with leaf area index and plant height but not with germination percentage. Multiple regression analysis showed that the first two growth attributes accounted for about 87% of the variability of yield. The dry matter yields of the second cuts were similarly affected by treatments but were about one‐half to one‐third those of the first cuts in 1978 and 1979 seasons, respectively. For the two seasons the average seasonal water‐use was about 1.02 times that of the U.S. class A pan evaporation. Water‐use efficiency increased from 15.6 to 43.9 kg/ha‐cm in 1978 and from 19.1 to 51.2 kg/ha‐cm in 1979, by irrigating every 7 days instead of 15 days, and applying 3N urea and 11.9 tonnes/ha gypsum.
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Claims 18
Claim · model-written summary
First-cut dry matter yield rose significantly with nitrogen level.
- Taxon
- forage sorghume0
- Treatment
- increase in N‐levele0
- Outcome
- dry matter yield of the first cutse0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“dry matter yield of the first cuts of forage sorghum increased significantly with increase in N‐level”
Claim · model-written summary
First-cut dry matter yield rose significantly as irrigation interval shortened.
- Taxon
- forage sorghume0
- Treatment
- decrease in irrigation intervale0
- Outcome
- dry matter yield of the first cutse0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“dry matter yield of the first cuts of forage sorghum increased significantly with increase in N‐level, with decrease in irrigation interval”
Claim · model-written summary
Gypsum significantly increased first-cut dry matter yield.
- Taxon
- forage sorghume0
- Treatment
- gypsum applicatione0
- Outcome
- dry matter yield of the first cutse0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“dry matter yield of the first cuts of forage sorghum increased significantly with increase in N‐level, with decrease in irrigation interval, and with gypsum application”
Claim · model-written summary
Reduced irrigation frequency had a greater effect than 3N fertilization.
Verbatim
e0“Decreased irrigation frequency had greater effect than 3N fertilization”
t0“Forage Sorghum”
Claim · model-written summary
Gypsum benefit was 5% at the seven-day irrigation interval.
Verbatim
e0“The benefits from gypsum application were low (5%) at the 7‐day irrigation interval”
t0“Forage Sorghum”
Claim · model-written summary
Combined treatment increased 1978 yield from 1.84 to 6.12 tonnes/ha.
Verbatim
e0“Dry matter yields were increased from 1.84 to 6.12 tonnes/ha in 1978 and from 3.20 to 7.23 tonnes/ha in 1979, by irrigating every 7 days instead of 15 days, application of 3N and 11.9 tonnes/ha gypsum”
t0“Forage Sorghum”
Claim · model-written summary
Combined treatment increased 1979 yield from 3.20 to 7.23 tonnes/ha.
Verbatim
e0“Dry matter yields were increased from 1.84 to 6.12 tonnes/ha in 1978 and from 3.20 to 7.23 tonnes/ha in 1979, by irrigating every 7 days instead of 15 days, application of 3N and 11.9 tonnes/ha gypsum”
t0“Forage Sorghum”
Claim · model-written summary
Height and leaf area index increased with nitrogen fertilization.
- Taxon
- forage sorghumt0
- Treatment
- N fertilizatione0
- Outcome
- Plant height and leaf area indexe0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“Plant height and leaf area index increased with N fertilization”
t0“Forage Sorghum”
Claim · model-written summary
Height and leaf area index increased with gypsum.
Not reportedComparator
Verbatim
e0“Plant height and leaf area index increased with N fertilization, with gypsum”
t0“Forage Sorghum”
Claim · model-written summary
Height and leaf area index increased as irrigation interval fell from 15 to seven days.
Verbatim
e0“Plant height and leaf area index increased with N fertilization, with gypsum and with reduction of irrigation interval from 15 to 7 days”
t0“Forage Sorghum”
Claim · model-written summary
Gypsum alone significantly increased germination percentage.
Not reportedComparator
Verbatim
e0“germination percentage was significantly increased by gypsum only”
t0“Forage Sorghum”
Claim · model-written summary
Yield was significantly correlated with leaf area index and plant height.
- Taxon
- forage sorghumt0
- Outcome
- Dry matter yielde0
- Value
- P = 0.01e0
- Comparator
- leaf area index and plant heighte0
Not reportedOrgan / stageDirection
Verbatim
e0“Dry matter yield significantly correlated (P = 0.01) with leaf area index and plant height”
t0“Forage Sorghum”
Claim · model-written summary
Yield was not correlated with germination percentage.
Not reportedDirection
Verbatim
e0“but not with germination percentage”
t0“Forage Sorghum”
Claim · model-written summary
Height and leaf area index accounted for about 87% of yield variability.
- Taxon
- forage sorghumt0
- Outcome
- variability of yielde0
- Value
- about 87%e0
- Comparator
- first two growth attributese0
Not reportedDirection
Verbatim
e0“the first two growth attributes accounted for about 87% of the variability of yield”
t0“Forage Sorghum”
Claim · model-written summary
Second-cut yields responded similarly but were lower than first-cut yields.
Verbatim
e0“The dry matter yields of the second cuts were similarly affected by treatments but were about one‐half to one‐third those of the first cuts in 1978 and 1979 seasons, respectively”
t0“Forage Sorghum”
Claim · model-written summary
Seasonal water use averaged about 1.02 times pan evaporation.
Verbatim
e0“the average seasonal water‐use was about 1.02 times that of the U.S. class A pan evaporation”
t0“Forage Sorghum”
Claim · model-written summary
Combined treatment raised 1978 water-use efficiency from 15.6 to 43.9 kg/ha-cm.
Verbatim
e0“Water‐use efficiency increased from 15.6 to 43.9 kg/ha‐cm in 1978 and from 19.1 to 51.2 kg/ha‐cm in 1979, by irrigating every 7 days instead of 15 days, and applying 3N urea and 11.9 tonnes/ha gypsum”
t0“Forage Sorghum”
Claim · model-written summary
Combined treatment raised 1979 water-use efficiency from 19.1 to 51.2 kg/ha-cm.
Verbatim
e0“Water‐use efficiency increased from 15.6 to 43.9 kg/ha‐cm in 1978 and from 19.1 to 51.2 kg/ha‐cm in 1979, by irrigating every 7 days instead of 15 days, and applying 3N urea and 11.9 tonnes/ha gypsum”
t0“Forage Sorghum”
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