Heavy Fertilization Research Articles

Is it possible by use of heavy fertilization to boost the small yields normally obtained from arable land with unfavourable natural qualities to the yield levels of favourable land?

Five field experiments, belonging to the Swedish long‐term soil fertility experimental project initiated in 1957, are situated in the very south of the country, two of them on land of favourable natural conditions and three on less favourable areas. The experimental design consists of all 16 combinations between four N and four PK treatments in two 4‐year crop rotations, with and without livestock. In the livestock rotation a clover/grass leg is cropped and cattle manure added once per rotation. One weakly (B1), one ordinary (C2), and one heavily (D3) fertilised NPK‐treatment in both crop rotations were examined in order to compare yields of less favourable with yields of favourable sites. The last five rotation sequences were used. In both rotations, D3 yields of the less favourable sites were superior to B1 yields of the favourable sites, except for winter wheat in the livestock rotation, for which the B1 yield at the favourable sites was superior. In contrast, D3 yields of the less favourable sites were generally lower than the C2 yields of the favourable sites except for clover/grass ley in the livestock rotation and oil seed rape in the rotation without livestock, for which the D3 and C2 yields were the same statistically.

Rice Yield by the Culture with Minimal Agricultural Chemicals in the Field with Continuous Application of Farmyard Manure or Chemical Fertilizer.

From 1991 to 2000, a rice cultivar, Koshihikari, was grown in the field, where either farmyard manure or chemical fertilizer was continuously applied. A minimal amount of herbicide and pesticide were applied only once after transplanting. Grain yield in the field with farmyard manure application alone was low owing to fewer spikes per plant. Farmyard manure may not supply enough nutrients for the production of enough tillers and spikes even by continuous application. Yield in the field with farmyard manure plus a small amount of chemical fertilizer was the highest though it fluctuated year by year. In the field with continuous application of a small amount chemical fertilizer without farmyard manure, spike number gradually decreased after several years, suggesting the lowering of soil fertility. In the field with continuous application of heavy fertilizer without farmyard manure, the yield was as high as that in the field with continuous application of farmyard manure together with a small amount of chemical fertilizer. It is concluded that continuous application of 200kg/a farmyard manure cannot raise the soil fertility enough to produce enough tillers and spikes for a high yield, but if a small amount of chemical fertilizer was applied together, we can obtain a relatively high yield without suffering from heavy panicle blast.

Relationship of readings from the LI-COR canopy analyzer to total one-sided leaf area index and stand structure in immature Douglas-fir

Estimation of leaf area is important in predicting potential growth. This estimation is often done by means of a photometer, such as the LI-COR plant canopy analyzer, but such instruments generally give biased estimates. Consequently, conversion factors are required to convert output from the photometer to the actual leaf area index (LAI). Foliar biomass was estimated in a 52-year-old Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) stand which had been treated with three levels of thinning and three levels of fertilization 28 years previously. The four treatment extremes (no thinning or fertilization up to heavy thinning and heavy fertilization) were sampled for foliage. Projected leaf areas were calculated from these biomass samples using specific leaf areas derived in a previous biomass sampling. Total one-sided leaf area was then computed by dividing the projected leaf areas by 0.9 to allow for lateral leaf curvature. In addition, LAI-2000 readings were taken in the same plots and then factors were derived to convert LAI-2000 readings to total one-sided LAI. These conversion factors were found to vary strongly with quadratic mean diameter, stand density, mean dbh, mean height and stand basal area. The effect of live crown height was minimal. These should allow the prediction of the conversion factor based on two or three of these highly correlated factors.

Long-term response of understory plant species to thinning and fertilization in a Douglas-fir plantation on southern Vancouver Island, British Columbia

The 27-year response of understory vegetation in a 51-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forest to thinning and N fertilization treatments was examined in a silviculture experiment at Shawnigan Lake on southern Vancouver Island of British Columbia. The experiment was a two-way factorial design with three levels for each of thinning and N fertilization. No significant treatment effects on the number of either vascular or nonvascular species were detected. This was also true for the covers of the majority of understory species except salal (Gaultheria shallon Pursh) and Oregon beaked moss (Kindbergia oregana (Sull.) Ochyra). Heavy thinning led to high salal and Oregon beaked moss cover, whereas heavy fertilization resulted in lower cover of salal but had no effect on the cover of Oregon beaked moss. Although thinning had a marginal effect on the cover of canopy trees 27 years after treatment, the cover of the canopy trees had only minimal effects on understory vegetation. Conversely, no adverse effect of understory vegetation on canopy trees was found. This study suggested that after 27 years thinning and fertilization had little effect on understory vegetation whether in terms of species richness or vegetation cover. An effective way to conserve species diversity is to protect specific substrate types, e.g., tree trunks, stumps, and coarse woody debris. A commercial thinning was recommended to reduce the time of stem exclusion in similar type of forests.

Effect of Dark Respiration on Dry Matter Production of Field-Grown Rice Cultivars. Comparison of growth efficiency between Nipponbare and Takanari.

The dry matter production, dark respiration rate and growth efficiency of high-yielding rice cultivar 'Takanari', grown under two levels of nitrogen fertilization (11, 17 gN / m2), were compared with those of 'Nipponbare' The crop growth rate (CGR) and leaf area index (LAI) were higher in 'Takanari' throughout the growth season. This higher CGR in 'Takanari' was due to the maintenance of NAR at the same level as in 'Nipponbare' in spite of the increase in LAI. The higher the nitrogen fertilization, the higher was the CGR due to the increase in LAI. The maximum dark respiration rate (Rs) in the whole plant was recorded at the early growth stage, followed by a rapid decrease until 40 days after transplanting and decreased gradually thereafter. The Rs in the whole plant and stems was higher in 'Takanari' as compared with 'Nipponbare' at the early stage, but was almost equal during the grain-filling period. The nitrogen concentration and Rs of the whole plant changed similarly, showing a close correlation between the two characters. The growth efficiency (GE) was about 64% during the early stage and gradually decreased thereafter in both cultivars irrespective of fertilization level. The GE during the grain-filling period was higher in 'Nipponbare' than in 'Takanari' and with the normal fertilization than heavy fertilization. We concluded that GE decreased at the later stage of plant growth due to increase in respiratory loss.

Long-term response of understory plant species to thinning and fertilization in a Douglas-fir plantation on southern Vancouver Island, British Columbia

The 27-year response of understory vegetation in a 51-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forest to thinning and N fertilization treatments was examined in a silviculture experiment at Shawnigan Lake on southern Vancouver Island of British Columbia. The experiment was a two-way factorial design with three levels for each of thinning and N fertilization. No significant treatment effects on the number of either vascular or nonvascular species were detected. This was also true for the covers of the majority of understory species except salal (Gaultheria shallon Pursh) and Oregon beaked moss (Kindbergia oregana (Sull.) Ochyra). Heavy thinning led to high salal and Oregon beaked moss cover, whereas heavy fertilization resulted in lower cover of salal but had no effect on the cover of Oregon beaked moss. Although thinning had a marginal effect on the cover of canopy trees 27 years after treatment, the cover of the canopy trees had only minimal effects on understory vegetation. Conversely, no adverse ef- fect of understory vegetation on canopy trees was found. This study suggested that after 27 years thinning and fertil - ization had little effect on understory vegetation whether in terms of species richness or vegetation cover. An effective way to conserve species diversity is to protect specific substrate types, e.g., tree trunks, stumps, and coarse woody de- bris. A commercial thinning was recommended to reduce the time of stem exclusion in similar type of forests.

Responses of Salsola kali and Panicum virgatum to mycorrhizal fungi, phosphorus and soil organic matter: implications for reclamation

1. Owing to the difficulty of finding terrestrial ecosystems without mycorrhizas, their influence on plant community dynamics is not easy to discern. This study utilized unreclaimed taconite mine tailings as a mycorrhiza‐free ecosystem to gain insights about the influence of arbuscular mycorrhizas and soil organic matter on the growth of Salsola kali (an early successional colonist of taconite tailings) and Panicum virgatum (a late successional grass planted during reclamation). 2. To assess relative mycorrhizal responsiveness, Panicum and Salsola were grown in taconite tailings along an experimental phosphorus gradient with and without mycorrhizal fungal inoculum isolated from reclaimed taconite tailings. At low phosphorus concentrations, mycorrhizal inoculum enhanced the growth (height and dry mass) of Panicum, but it decreased growth at the two highest phosphorous concentrations. At no phosphorus level did mycorrhizal inoculum enhance the growth of Salsola but it decreased growth at the highest phosphorus concentrations. 3. In field plots, mycorrhizal inoculum and organic soil amendment (compostedpapermill sludge) enhanced the growth of Panicum and decreased the growth of Salsola. 4. In this experiment, mycorrhizal inoculum enhanced the growth of the late successional grass but, during reclamation operations, manipulating edaphic conditions to favour mycotrophy may be more cost‐effective than large‐scale inoculation. The results of this study suggest that mycotrophy is favoured by increasing soil organic matter and avoiding heavy fertilization.

Distribution, Disturbance Tolerance and Conservation of Stackhousia gunnii in Tasmania

Although being possibly widespread on the mainland of Australia, where it is recognised as part of the Stackhousia monogyna Labill. complex, S. gunnii Hook.f. is an endangered species in Tasmania, with only 10 known extant populations, all in the drier parts of the southern Midlands. These populations occur largely on roadsides or lightly grazed paddocks in vegetation that was originally either Themeda triandra grassland or Eucalyptus pauciflora woodland. An ordination of floristic data from sites with and without S. gunnii showed that the species occupies a floristically distinct environment. The floristic differences between stands of S. gunnii relate partly to the presence or absence of tree cover and substantially to precipitation. The groups of species that preferentially occur with S. gunnii are geophytes, non-geophytic herbs and exotic plants, while those that are concentrated elsewhere include shrubs, grasses and non-geophytic graminoids. Permanent transects were monitored over a 4-year period at seven sites with varying grazing, firing and disturbance. The number of shoots varied markedly between years in all sites, but not synchronously, even when transects were in close proximity. Although shoot numbers increased after fires occurred on several ungrazed transect lines, they decreased on one grazed line. Deep mechanical disturbance of one site resulted in a dramatic decrease in shoot numbers in the following year. However, they increased steadily over the following 2 years. Shoot emergence occurred at twice the expected rate on bare ground in all years and at all sites, and a substantial proportion of shoots was confined to this type of surface. However, shoots were also recorded in fewer numbers in grass cover, herb cover and non-vascular plant crusts. Like some other threatened plants of grassy ecosystems, S. gunnii seems to be rare because it cannot survive with heavy grazing disturbance, ploughing and fertilisation, and, at the other extreme, because it is susceptible to elimination in the absence of environmental conditions and disturbances that create bare ground.

Nitrogen Dynamics and Balance in Intensified Rainfed Lowland Rice‐Based Cropping Systems

AbstractNitrogen dynamics and balances in intensive and diversified lowland rice (Oryza sativa L.)‐based cropping systems that receive heavy fertilization, tillage, and irrigation have not been explored. Such information is essential to improve the efficiency of N fertilizer, an input based on a nonrenewable energy resource and whose oxidized products pose hazards to human health and the environment. Field experiments at an experimental farm on an Inceptisol and in two farmers' fields, one with an Inceptisol and one with a Vertisol soil, quantified (i) NO‐3‐N and NH+4‐N in different soil layers in relation to water‐filled pore spaces (WFPS), (ii) N balance, and (iii) systems‐level N efficiencies in several cropping patterns. Nitrate‐N and NH+4‐N were quantified monthly from July 1993 to June 1994. The WFPS remained <0.80 mL mL‐1 in the beginning of the wet season and throughout the dry season that enhanced nitrification. Ammonium‐N in the 100‐cm layer was 20 to 40 kg ha‐1 in the wet season and <10 kg ha‐1 in the dry season. Nitrate‐N, however, ranged from 27 to 54 and from 67 to 195 kg ha‐1 in the two seasons; it was higher in farmers' fields (192–195 kg ha‐1) than in the experimental farm (67–112 kg ha‐1). Total N loss was 34 to 549 kg ha‐1 across sites, with the largest in rice‐sweetpepper (Capsicum annuum L. var. annuum) and rice‐tomato (Lycopersicon esculentum Miller). Despite a lack of a consistent trend in N efficiency among the different cropping systems, it was higher with tobacco (Nicotiana tabacum L.) and garlic (Allium sativum L.). There appears an opportunity to grow a NO‐3 catch crop during the dry‐wet transition in rice‐sweetpepper and rice‐tomato systems to capture and recycle soil NO‐3‐N.

Does atmospheric deposition of nitrogen threaten Swedish forests?

The health and productivity of forests is fundamentally important to many societies, and the culture and economy of Sweden are intimately linked with Sweden's forests. Are the health and productivity of Sweden's forests at risk from too much nitrogen from acid deposition? We evaluated this question by posing a number of specific questions, and synthesized information from the extensive research in Sweden on N deposition, fertilization and forest growth. We addressed the questions: Have Swedish forest soils acidified in recent decades? Are Swedish forest saturated with N, or do they have an excess of N? Will excessive N lead to forest decline? Will liming or vitalisation fertilization improve forest nutrition and health? We examined the ideas behind these questions, the available evidence, and whether the evidence supported or refuted the ideas. Several studies have documented reductions in soil pH (measured in water) in Swedish forests over periods of several decades. This acidification has been accompanied by increases in ionic strength of soil solutions, reduced base saturation and increased soil organic matter. The importance of each of these acidifying processes has not been investigated directly, but evidence supports a substantial role for each mechanism in at least some cases. Current expectations about rates of mineral weathering are not consistent with the evidence; rates of weathering appear to be greater than expected, and to differ depending on tree species. Swedish forests are not saturated with N; only a few stands near the southwest coast (with the highest deposition rates) show leaching losses of N that rival N deposition rates. Across all regions of Sweden, inadequate supplies of N limit forest growth. Within each region, some stands fail to respond to N fertilization (or respond with a decrease in growth), which is common for other forest types in other countries. Stands that have received heavy fertilization with N may become responsive to further fertilization with phosphorus (P) or base cations, and fertilization with trace amounts of boron (B) may be important on some soils. No evidence supports any widespread responsiveness of the forests to fertilization with other elements unless N is also added. Vitalisation fertilization (with non-N nutrients) has not demonstrated substantial improvements in tree growth, although most experiments have focused on N-limited sites rather than N-excess sites. Liming studies from Sweden and around Scandinavia indicate that forest health typically suffers after liming, including growth losses of 5 to 10% lasting one or more decades. The forests of Sweden averaged about 30% greater growth per hectare in the 1990s than in the 1950s, and extensive forest inventories show no indication of abnormal forest declines within this overall picture of improving growth. Hypotheses of declining forest growth as a function of the ratio of base cations to aluminum in soil solution can be tested with N fertilization experiments. The cation ratios uniformly declined with N fertilization, but growth typically increased, refuting the idea that cation ratios can represent changes in forest productivity. We conclude that no evidence supports the hypothesis of past or current deposition of N has reduced the health or productivity of Sweden's forests; the opposite may have occurred. We also stress that several important questions cannot be addressed satisfactorily with current information. In particular, we recommend additional research on sites where N leaching rivals N deposition, elucidating mechanisms controlling N leaching and responses of trees to excessive levels of soil N.

Sustainable Traditional Agriculture in the Tai Lake Region of China

Traditional agriculture in China's Tai Lake Region sustained high productivity for more than nine centuries. This article examines the ecological basis for this high long-term productivity in a historical context, with a focus on the role of nutrient limitation. From 1000 AD to the 1950s, agricultural technology remained basically unchanged, as did the yields of rice, wheat and other crops. Still, total grain production and net farm income increased over time, as a result of increased multiple cropping, expanded mulberry/silk production, and the intensified use of organic fertilizers. Without degrading soil resources, continuous intensive farm management supported the nutritional and other needs of the rural population, which grew to nearly ten people per hectare of cultivated land by the 1930s. Ecological limitations to human carrying capacity that seem apparent in the mid 1800s appear to have been overcome since the 1960s by chemical nitrogen subsidy of agroecosystems. Human populations are now nearly twice their traditional maximum, and the region remains one of the world's most productive agricultural regions thanks in part to heavy fertilizer applications that have changed nitrogen from a limiting nutrient to a potential source of pollution. Whether these high inputs and/or other agricultural technologies will continue to sustain food self-sufficiency for the region's farmers remains to be seen. The high long-term productivity of Tai Lake Region agroecosystems make them ideal for study of the ecological basis for sustainable agriculture.

Agricultural BMPs for Phosphorus Reduction in South Florida

Four sets of eight or twelve 0.7 ha plots, designed for soil and hydraulic uniformity, were used to screen potential Best Management Practices (BMPs) for reducing total phosphorus (TP) concentrations and loadings in the Everglades Agricultural Area (EAA) of south Florida. The four production systems and their alternatives (treatments) studied were: (1) sugarcane (interspecific hybrids of Saccharum sp.) versus drained fallow plots; (2) fast versus slow drainage rates for sugarcane; (3) rice (Oriza sativa L.) in rotation following radishes to serve as a P filter crop versus traditional flooding fallow; and (4) banding phosphorus (P) fertilizer at 50% of the soil-test recommendation rate for cabbage (Brassica oleracea L.) versus full-rate broadcast applications. The study showed that there were no differences in P concentrations in drainage water between sugarcane and drained fallow fields. Annual P loading to the plots in rainfall and irrigation water (0.63 kg TP ha1) exceeded the P loading of drainage waters (0.52 kg TP ha1 for sugarcane and 0.59 kg TP ha1 for drained fallow plots). Slow drained sugarcane plots exhibited significantly higher TP concentrations than the fast drained plots. However, TP loads were significantly higher (0.97 kg ha1) for fast drained plots than for the slow drained plots (0.67 kg ha1). Rice as a P filter crop following radishes reduced TP concentrations and loadings. Finally, banding P fertilizer at a reduced rate for cabbage reduced TP concentrations compared to those for broadcasted P at the full recommended level. Total phosphorus loadings in drainage water were 1.17 kg ha1 for banded and 1.38 kg ha1 for broadcast treatments. A total of 1.30 kg TP ha1 entered the plots in rainfall and irrigation water. All treatment TP loadings leaving the plots in drainage water were close in magnitude to TP loadings to the plots, even under heavy fertilization. This indicates that the EAA system is currently a net assimilator of P.

Use of polyolefin-coated fertilizers for increasing fertilizer efficiency and reducing nitrate leaching and nitrous oxide emissions

This paper reviews some of the benefits of polyolefin-coated fertilizers (POCFs) with accurate controlled release properties. They are helpful in developing innovative rice farming systems, such as no-till direct seeded rice with single basal fertilization and transplanting of rice seedlings with single basal fertilization. These new cultivation systems can increase fertilizer efficiency and reduce farming costs. The recovery of basal N can be increased from 22–23% with conventional broadcast application of ammonium sulfate or urea to 79% withco-situs application of polyolefin-coated urea. The no-till rice cultivation of transplanting of rice seedlings with single basal application of POCFs decreased the farming cost by 65% as compared to that of the conventional rice cultivation. Theco-situs application of POCFs containing NPK reduced nitrate leaching and nitrous oxide emissions from cultivated soils with heavy fertilization. Since POCFs have various nutrient composition and release types, a variety of application methods to agricultural and horticultural plants are being developed in Japan.

Spreader Patterns Using ASAE S341.2 Compared to Patterns in Golf-cup Sized Holes in Turfgrass

ASAE Standard S341.2 (1993), Procedure for Measuring Distribution Uniformity and Calibrating Broadcast Spreaders, specifies a procedure for conducting pattern tests under controlled situations. The Standard does not specify the surface on which the tests are to be conducted, and thus a paved surface is frequently used for pattern testing. Conducting the tests on a hard surface allows particles to bounce into the collection trays, thus distorting the apparent pattern. A comparison was made between pattern tests conducted according to ASAE S341.2 on smooth concrete and on two species of turfgrass. For the turfgrass tests, the samples were collected in plastic cups set flush with the thatch in round holes cut by a golf cup hole cutter. This procedure eliminated particles bouncing out of the collection devices and allowed bouncing in only to the extent present in actual application to turfgrass. The results showed a major change in both pattern width and apparent delivery rate with large, heavy fertilizer particles. The results verified that a large amount of material bounced into the collection trays in the standard lab tests, thus giving a distorted view of the pattern. With small, light particles, the difference was much less pronounced since less bouncing occurred with those products in the standard laboratory tests.

Varietal Difference on Morphological Change of Leaf Blade by Different Nutrient Concentration of Culture Solution in Rice Seedlings.

To make clear the internal leaf morphology concerned with varietal difference in specific leaf area (SLA) response to concentration of culture solution at the seedling stage, varietal differences in leaf morphological change with the advance of leaf position and in the response of leaf morphogenesis to nutrient concentration were investigated. Vascular bundle number (VBN) in transverse section of leaf blade and leaf width increased with the advance of position, but VBN did not increase with leaf width. Increase of leaf length with the advance of position was the greatest in NNN-type wherein nitrogen content per leaf area (NCLA) increased but SLA did not increase with nutrient concentration increase. The increase of VBN and leaf width in NNN-type were less than others. However, exceptionally in Dular, which was a variety in SSN-type wherein SLA increased with nutrient concentration, the VBN did not increase with nutrient concentration and was much more than others at every concentration. In the relationship between leaf width and length, leaf area expansion of NNN-type depended on leaf length, but others depended on leaf width increase. From these results, it was clear that SLA increase with heavy fertilization was extremely large in the varieties having many VBN by nature, and getting remarkable increase of VBN in response to fertilizer increase. Then, presumably, to improve rice productive ability efficiently in connection with fertilization, it is important that varieties have the characters, i.e. VBN and leaf width do not increase, leaf area expansion depends on the increase of leaf length, and moreover leaves are erect even under heavier fertilizer conditions.

A Leaf Spot and Blight ofAbelmoschus moschatusCaused by a Pathovar ofPseudomonas syringae

A fluorescent bacterium that closely resembled Pseudomonas syringae pv. hibisci in morphological, biochemical, and physiological tests was consistently isolated from Abelmoschus moschatus with a leaf spot and blight. The bacterium also caused foliar symptoms on several Hibiscus species, including H. rosa-sinensis. Strains of P. s. hibisci attacked A. moschatus but were markedly less agressive on that host than was the strain from Abelmoschus. On A. moschatus, disease development was favored by low temperatures (20-25 C) and succulent plant growth resulting from heavy fertilization. The bacterium was seedborne, as it was recovered from seed stored for 10 mo at 10 C

Variation in the supracritical nitrogen concentration of kikuyu grass

Abstract The N concentration was monitored in grazed pastures of kikuyu (Pennisetum clandestinum) where regular applications of nitrogen fertilizer removed any nitrogen deficiency for growth. The heavy fertilizer applications maintained supracritical N concentrations of 3.7–5.3% in the last fully‐formed laminae. The concentration increased with increasing temperature or growth rate, but not with changing soil water content. Supracritical N concentrations will buffer the onset of a N deficiency, and the difference between the actual and critical N concentrations provides a quantitative measure of reserve N. Estimates of reserve N in a heavily fertilized pasture with a top yield of 2,000 kg DM/ha, ranged from zero to 32 kg N/ha. This is sufficient to supply N to an additional 0–914 kg DM/ha without diluting the average N concentration below the critical level.

Did New England Go Downhill?

Did New England Go Downhill?

Changes in the distribution of carabid beetles in The Netherlands since 1880. II. Isolation of habitats and long-term time trends in the occurence of carabid species with different powers of dispersal (Coleoptera, Carabidae)

The effects of habitat isolation on the occurrences of carabid species over a period of 110 years are studied, as part of a more general treatment of the changes in the fauna of carabid beetles of The Netherlands. According to the founding hypothesis of Den Boer (1977), poorly dispersing species are expected eventually to disappear from small and highly isolated habitat fragments. The time trends in the occurrences of well and of poorly dispersing species since about 1880 are compared by estimating the numbers per decade of occupied 10 × 10 km squares of the distribution maps. These figures are corrected for changes in collecting intensity. Poorly dispersing species generally show decreasing time trends, whereas the occurrences of well dispersing species appear to be more stable, or increasing. A test group of well dispersing species with a high tolerance for agricultural treatments, especially heavy fertilisation, show distinctly increasing time trends, as expected. The quantitative significance of habitat isolation, in comparison to habitat destruction, as an explanation of the gradual disappearance of species with low powers of dispersal, will be the subject of further studies.

Studies on the Dry Matter Production of Napiergrass. III. Areas and light-photosynthesis relations in single leaves from different positions on a stem at Tokyo and Miyazaki.

Napiergrass (Pennisetum purpureum Schumach, cv. Merkeron), grown in Tokyo and Miyazaki under relatively heavy fertilization, produced 31∼32 unfolded leaves on a stem, 20 leaves of which were lost by senescence, during the growing season from May to November. At both sites, the area of a leaf was the largest for the 23rd leaf on a stem, numbered consecutively from the lowest leaf above ground level. The area of this leaf, unfolded in late August, was ca. 370 cm2 in Tokyo and ca. 300 cm2 in Miyazaki, although the areas of 11∼13th leaves, unfolded in early July, were considerably smaller at the former site. Owing mainly to such circumstances as above, the increase in leaf area index and leaf area density until early September were more rapid in Tokyo than in Miyazaki. At both sites, the photosynthetic rate of single leaf under high light intensity was the highest for the leaves around the uppermost unfolded leaf with a value of ca. 90 mg CO2/dm2/hr and light-photosynthesis relations of these leaves were the ordinary type for C4-grasses. The older the leaf, the lower was the photosynthetic capacity and the more the light-photosynthesis curve tended towards the light-saturation type.