Intercepted Radiation at Flowering and Kernel Number in Maize: Shade versus Plant Density Effects

Well-watered crops of sweet sorghum (cv. Wray) and forage sorghum (cv. Silk) were grown in south-eastern Queensland. Treatments consisted of four sowing dates, two intra-row spacings and harvests taken at six physiological growth stages from the third ligule to 3 weeks after grain maturity. Plant density effects on the concentration of sugars and nitrogen were slight, and changes in yields of these components were a function of density effects on dry matter yields. At any growth stage, the concentration of sugars in both cultivars was decreased with delay in sowing date. The delay in sowing date led to an increased nitrogen concentration in cv. Wray, but in cv. Silk the nitrogen concentration was highest in early and late sowings. At maturity, the concentration of sugars in cv. Wray averaged 40'70, 10 times the level in cv. Silk. In both cultivars, accumulation was a near linear function of either time or radiation sum. The partitioning of carbohydrate differed little between cultivars but altered with their ontogeny. The efficiency of light use for sugars production was greater in cv. Wray and altered with ontogeny. In contrast, concentration of nitrogen was similar for both cultivars and decreased curvilinearly with time or degree days. The partitioning of nitrogen altered with ontogeny and the amount partitioned to leaf material was greater in cv. Silk pre-anthesis but was less post-anthesis. Yield of stem sugars in cv. Wray exceeded 10 t ha-1 when the crops were sown early in the season, but was only 3 t ha-1 with late-sown crops.

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The Relatioship between Plant Density and Microclimate and Nutmeg (Myristica fragrans Houtt) Production in Nutmeg and Coconut Mixed-Planting System in Wakatobi District in Indonesia

Journal of Agricultural Science ◽

10.5539/jas.v7n12p187 ◽

2015 ◽

Vol 7 (12) ◽

pp. 187 ◽

Cited By ~ 1

Author(s):

Abdul Madiki ◽

Bambang Guritno ◽

Syekhfani Syekhfani ◽

Nurul Aini

Keyword(s):

Relative Humidity ◽

Plant Density ◽

Density Ratio ◽

Optimum Number ◽

Transmitted Radiation ◽

Coconut Tree ◽

Myristica Fragrans Houtt ◽

Observation Method ◽

Intercepted Radiation ◽

Close Distance

In Wakatobi district nutmeg trees are generally cultivated in mixed planting with coconut. The research employed observation method where sample plants were determined purposively based on intersection of nutmeg and coconut tree crowns; 42 plots of pairs of nearest neighboring plants. In each plot of pair of plants, plant density of nutmeg and coconut was calculated (individually and in total), then microclimate components (solar radiation, temperature and relative humidity) and nutmeg plant characteristics (vegetative and prodution components) were measured. Research results showed that plant density of nutmeg (218 plants ha-1) had exceeded its optimum number of population, plant density of coconut 144 plants ha-1 with relative density ratio of 58:42% or nutmeg was more dominant than coconut. Transmitted radiation and temperature below the crown was decreasing, and in contrast, intercepted radiation and relative humidity increased in line with the increased plant density of nutmeg. This condition led to the decrease in sum of fruits, weight of mace, and weight of kernel of individual nutmeg tree. Coconut plant density had non-significant correlation and non-significantly contributed to microclimate and production components of nutmeg. This indicated that the tendency for decreased production of nutmeg is less affected by coconut trees, but more because of shading effect of nutmeg trees due to close distance among them. In other word, there occured intraspecific competition (nutmeg and nutmeg), and not interspecific (nutmeg and coconut). Therefore, coconut can be cultivated in mixed planting with nutmeg through appropriate plant spacing.

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Response of chickpea accessions to row spacing and plant density on a vertisol on the Darling Downs, south-eastern Queensland. 2. Radiation interception and water use

Australian Journal of Experimental Agriculture ◽

10.1071/ea9880377 ◽

1988 ◽

Vol 28 (3) ◽

pp. 377 ◽

Cited By ~ 13

Author(s):

GJ Leach ◽

DF Beech

Keyword(s):

Water Use ◽

Dry Matter ◽

Plant Density ◽

Incident Radiation ◽

Row Spacing ◽

Radiation Interception ◽

South Eastern ◽

Early Afternoon ◽

Wide Range ◽

Intercepted Radiation

Interception of radiation by chickpea (Cicer arietinum L.), in a year of below-average rainfall, and water use in both wet and dry years, were studied on a deep vertisol soil at Dalby, south-eastern Queensland. Measurements were made on 4 accessions (cv. Tyson, K223, CPI 56287 and CPI 56289) grown at a number of row spacings. Canopies intercepted less than 20% of incident radiation during the first 70 days after sowing (DAS) in the dry year (1980) before radiation interception reached a peak in mid-September (100 DAS) at about 70% interception in 250 mm rows. Above-ground dry matter was linearly related to intercepted radiation to the end of September (119 DAS), giving an efficiency of radiation conversion of 1.4 g DM per MJ of intercepted photosynthetically active radiation. Efficiency of conversion was marginally higher with 125 mm than with 62.5 mm intra-row spacing in rows 250 mm apart. In a wet year (1979), chickpea extracted water from below 1 m depth in the soil profile and used 356 mm water. In the dry year, only 16 1 mm water was used and none was extracted from below 1 m. K223 used water faster than cv. Tyson, and extraction was faster with close than with wide row spacing. Above-ground dry matter was produced at an efficiency of 3.4 (1980) to 4.2 (1979) g m-2 mm-I of water during the main period of growth through September, and a mean of 0.7 g m-2 seed for 2 seasons was produced per mm of water used over the whole season. The small differences in water extraction between accessions and spacing treatments were reflected during pod-filling as differences in plant water potential of 0.1-0.2 MPa during the early afternoon stress period. Chickpea appears to have poor stomata1 control over water loss, being comparable to summer legumes like soybean rather than to cowpea. We conclude that the benefit of close row spacing in enhancing radiation interception outweighs the small disadvantage from accelerated water depletion. The ability of chickpea to produce useful seed yields over a wide range of soil water availability makes it well suited for opportunistic winter cropping.

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