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SummaryAmmonium nitrate was applied to a kikuyu (Pennisetum clandestinum) dominant pasture at annual rates of 0, 134, 336 and 672 kg N/ha. Each nitrogen (N) rate treatment was continuously grazed at three stocking rates (SR) designed to apply similar grazing pressures at each N level and covering a range from 2·2 to 16·6 Angus weaner cattle/ha.The N status of these pastures was periodically assessed 8–10 weeks after seasonal N applications by temporarily excluding stock and measuring D.M. and N response to additional ammonium nitrate application. Pasture growth response to additional N was constant and independent of SR and of annual N rate over the range 0 to 336 kg N/ha, despite wide variation in pasture availability. N concentration of plant shoots was increased by high SR and rate of N uptake was not significantly affected by SR. Pasture growth rate was positively related to annual N rate.Herbage yield of kikuyu leaf, stem and litter on offer, was negatively related to SR but weight of underground organs was unaffected. Increasing SR increased the proportion of leaf and the rate of tillering. Pasture availability was positively and linearly related to N rate from 0 to 336 kg N/ha and maximal at 336 kg N/ha; the size of the litter fractions and underground organs was generally independent of N rate. N% in leaf and stem was reduced at low SR; N% of leaf, stem, litter, rhizome and root was positively related to N rate which was more influential than SR. The effect of SR on the size and relative distribution of the N in plant tops and litter fraction is discussed.Kikuyu dominance was positively related to N rate and independent of SR. White clover invaded at No and N131 levels especially at a high SR.

A better understanding of the response of kikuyugrass (Pennisetum clandestinum Hochst. ex Chiov.) to management and climate is needed in order to best exploit this important forage grass. The objective of this study was to describe kikuyugrass regrowth under a variety of conditions and to relate regrowth performance to N-nutrition, environment, and sward characteristics. Kikuyugrass swards at two locations (Kula, 945 m elevation, and Makawao, 660 m elevation) were trimmed and fertilized with three levels of N (22, 56, and 168 kg/ha) at 10-week intervals. During alternate 10-week periods, plots were cut sequentially after 4, 6, 8, and 10 weeks of regrowth. Regrowth began slowly after a 10-week period, especially at Kula during the cool season. Changes in the area: dry weight ratio of the forage indicated that this may have been due to retarded leaf development under low temperatures. At other times, regrowth at both locations was normally rapid after the 4th week and continued at a high rate through the 10th week. About 600 kg/ha of harvestable green vegetation (DM basis) were required support subsequent near-maximum growth rates. This was equivalent to 8 cm harvestable height, 30% interception of blue light, and a leaf-plus-stem area index of 1.0. Crude protein (CP) yields tended to level off after weeks, especially during the warmer months. Percent CP in the low and moderate N treatments declined during the regrowth period from approximately 16 to 18% at 4 weeks to 8% at 10 weeks. Percent CP in the high-N treatment was higher but more seasonally variable; 4-week regrowth contained over 30% CP equiv, during the cooler months. Some of this N was present as NO₃ which ranged from 20 ppm NO₃-N (low or moderate N-level, 8 weeks regrowth) to over 2000 ppm (high N-level, 2 to 6 weeks growth at Makawao). Nitrate levels thus approached potentially toxic concentrations for ruminants in some cases. Multiple regression analysis identified several factors as being significantly associated with growth rate: nitrogen nutrition of the sward, temperature (air or soil), and position on the growth curve. Unidentified site factors were also determinants.

SummaryIndividual live-weight gain (LWG) of Angus weaner cattle continuously grazing (Pennisetum clandestinum) pasture was negatively and linearly related to stocking rate (SR) and independent of ammonium nitrate (N) application rate at similar grazing pressures.Live-weight gain varied from 380 to 1056 kg/ha according to N rate in 1970–1 and from 637 to 1477 kg/ha in 1971–2. Calculated SR giving maximum LWG/ha was 3·4, 4·7, 7·6 and 9·8 animals/ha for the 0, 134, 336 and 672kg N/ha treatments respectively in 1970–1 and 6·1, 5·7, 9·1 and 10·6 animals/ha for the same treatments in 1971–2. Highest response to applied N (1·9 and 3·4 kg LWG/kg additional N in successive years) occurred between N131 and N336; response was greater at low and intermediate SR than at high SR. Carcass weight, quality score, depth of subcutaneous fat and area of eye muscle were negatively related to SR; SR's giving maximum output per unit area caused a reduction of ca.25% in production per head and adversely affected carcass quality at 18 months of age.LWG/head was independent of feed availability in spring and summer and was positively related to availability of green kikuyu up to 600 kg D.M./head in the autumn/winter period.

Investigations to determine whether frosted kikuyu could supply better quality foggage than natural pasturage in sourveld areas during the winter months revealed that this grass was characterized by a crude protein content of 8–10% in the winter months. The performance of animals grazing such frosted kikuyu was highly satisfactory.

IF A successful poultry industry is to be developed in countries of the American Tropics, local vegetable sources of protein, riboflavin, and vitamin A activity must be exploited. Forages grow rapidly in the Tropics; and several promise to contribute large quantities of nutrients essential for adequate poultry rations. Desmodium, Desmodium intortum, has been shown to be equal to a United States alfalfa meal in baby chick rations (Squibb et al., 1950) and is found throughout the American Tropics as well as in the southern United States. Kikuyu grass, Pennisetum clandestinum, grows well at most altitudes in Central America. It has been found to be an excellent supplement to corn and sesame oil meal for swine on dry lot (Squibb et al., 1951). As a pasture, according to unpublished data by Squibb, it also maintains high serum levels of riboflavin, vitamin A, and carotenoid levels in laying hens. Another plant that …

Le Meloidogyne kikuyensis n. sp. differe des autres especes du genre Meloidogyne par la forme caracteristique de la partie anale chez les femelles. Le patron cuticulaire posterieur montre un arc dorsal bas, plus ou moins carre, des joues typiquement striees de chaque cote du vulve et une figure sinussoidale entourant l'anus en dessous du cuticle. Les larves different de toutes les autres especes excepte de M. africana et M. inornata. Le mâle de M. kikuyensis differe de M. africana et M. inornata (Lordello, 1956) par le quadrillage sur toute la longeur des cotes lateraux et par le nombre constant des raies qui est toujours de quatre.

The author studied in this paper effect of chicory (Chicorium intybus L.), kikuyugrass (Pennisetum clandestinum Hoahst) and a variety of Bermuda grass (Cynodon dactilon Pers.) named "Grama seda" as green feeds in growth of White Leghorn chickens (0-8 weeks). Males and females were se-pareted by feathering and development of comb. The results obtained can be summarized as follows : a) - Without separation of sex, the chickens that received green feeds showed better development than that did not receive green suplements. b) - The chicory showed to be something better that kikuyugrass and Bermuda grass, which had a similar effect. c) - The green feeds used had little influence in development of males. d) - The females in the lots suplemented by green feeds showed to be superior to the females in the lots that did not receive it. e) - The author think that the presence of some priciples having action in the female hormony function is responsable for the better growth in the lot that received green feeds.

AS A RESULT of the low vitamin A intake during extended dry seasons, vitamin A deficiency is a severe nutritional problem of animals in the American tropics. It is now apparent that not only inadequate dietary intakes but also high environmental temperatures (Squibb, Guzman and Scrimshaw, 1954) and, in poultry at least, diseases such as coryza and cholera (Squibb et al., 1955) are additional factors responsible for low serum vitamin A levels in animals. All of these are common stress factors in the tropics. Squibb, Guzman and Scrimshaw (1953, a, b, c) and Squibb, Mendez, Guzman and Scrimshaw (1954) have demonstrated that vitamin A deficiencies may be overcome by feeding dehydrated forage meals prepared from kikuyu grass (Pennisetum clandestinum), ramie (Boehmeria nivea), Desmodium sp., especially the species D. intortum, or banana leaves. In this report the utilization of the carotenoids of four additional forages was evaluated in New Hampshire chicks. . . .

(1971). In-Vivo Digestibility and Nutritive Value of Kikuyu Grass Pennisetum Clandestinum with a Tentative Assessment of Its Yield of Nutrients. East African Agricultural and Forestry Journal: Vol. 37, No. 1, pp. 15-21.

Distances moved by Cicadulina spp. were investigated at Salisbury, Rhodesia, during 1968–69, by using small plots of oats to trap adults dispersing from populations breeding in Pennisetum clandestinum or Eleusine indica grasses. The shape of the curves constructed for fall of numbers with distance confirmed laboratory findings that populations are composed of long and short distance fliers. The curve for numbers of infective Cicadulina punctures estimated from the gradient of maize streak infection falling from adjoining cereals was also of similar shape. Mean flight times indicated that a steep fall for about 10 m from source is due largely to short distance fliers making trivial movements, and the subsequent gentle fall is due to long distance fliers which may disperse many kilometres depending on the wind speed. There were higher proportions of long distance fliers amongst C. mbila (Naudé) compared to C. storeyi China, and amongst females compared to males dispersing downwind. A predominance of long distance fliers dispersing from drying grasses during April–September, and of short distance fliers present in irrigated grasses and cereals during October–March, causes seasonal differences in the patterns of maize streak infection and in the effectiveness of barriers of clear ground as a preventive measure.

The relative growth rate of tops (RT) of Nandi setaria (Setaria anceps cv. Nandi), kikuyu (Pennisetum clandestinum). pangola (Digitaria decumbens) and Biloela buffel grass (Cenchrus ciliaris cv. Biloela) in pot experiments was a curvilinear function of the % N in the blades of the youngest fully‐expanded leaves on vegetative tillers (leaf N). The mean RT's differed significantly between grasses, but the response curves did not deviate significantly from being parallel. The mean quadratic curve for vegetative growth of Nandi setaria predicted increasing RT as leaf 11 rises from below 1 to about 3%, and near‐maximum RT between 3 and 6% N.

The relative frequency of occurrence of plants (or plant parts) is determined at increasing distances from a focus, where the relative frequency is unity. The area under the resulting frequency/distance curve is determined, as a measure of spread. Effect of treatments on spread can be compared by comparing these areas. A rate‐of‐spread index can be calculated from areas determined at successive times. A model is proposed which enables the area under the curve to be estimated from only three (or even two) frequency determinations. The amount of field work is thereby much reduced. Use of the model is illustrated by comparing the spread of Pennisetum clandestinum (kikuyu) and several Cynodon cullivars in a nursery.

1. The results of nine digestibility trials on three East African grasses, using sheep as experimental animals, are reported.2. In five of the trials Bothriochloa insculpta, at various stages of growth during the season, was used. Chloris gayana (Rhodes grass) was used in two trials, as was Pennisetum clandestinum (Kikuyu grass).3. The results are discussed and are compared with other results from East Africa.4. P. clandestinum has a high digestible protein content and is highly digestible in the early stages of growth, and maintains its high protein content when 9 to 12 in. in height.5. Bothriochloa insculpta and Chloris gayana are moderately highly digestible in the-young stages but are relatively low in digestible protein. As growth ceases during the dry season the digestible protein content falls more rapidly than the starch equivalent with consequent widening of the nutritive ratio.6. It is suggested that the differences between Pennisetum clandestinum and the other grasses may be due to its predominantly vegetative habit.

Direct visual estimates of average foliage height based on a 28 x 28 cm sampling area could be made at a rate of 7.5 readings/minute using a new device which utilized a plastic fresnel lens. Foliage height was estimated (5 readings/plot) for kikuyugrass (Pennisetum clandestinum Hochst. ex. Chiov.) and pangola digitgrass (Digitaria decumbens Stent) swards which varied widely in yield due to different nitrogen and gibberellic acid treatments. Average foliage height explained 94% of the variation in dry matter yields in both cases, but the regression slope was different for the two grasses. Sampling error was low in relation to experimental error. The calculated number of samples required to estimate the mean foliage height was 8 to 9 samples/ plot for estimates ±2 cm and 4/plot for ^3 cm (P = 0.95). This approach appears especially promising for estimating forage growth rates where nondestructive sampling is desired and where swards are variable, i.e. as in grazed paddocks

Kikuyu grass herbage (Pennisetum clandestinum) contained higher levels of cell-wall constituents than perennial ryegrass (Lolium perenne) grown under identical conditions. Much of this difference was due to hemicellulose rather than cellulose. A similar pattern was obtained with leaf blades from glasshouse-grown plants of the two species. Kikuyu grass stolons and leaf sheaths contained higher levels of structural carbohydrates than their corresponding leaf blades. In all of the kikuyu plant parts analysed the hemicellulosa level was 90-100% of the cellulose level. In leaf blades and sheaths of a second Pennisetum (P. typhoides) the level of hemicellulose was much lower than that of cellulose, which is typical of most festucoid and panicoid grasses.

Tesis (Mag. Sc.) -- IICA, San José (Costa Rica), 1974 Baba de culebra, "salivita" o "espumita de los pastos" son los nombres vernaculares con que generalmente se conoce a varias especies de insectos de la familia Cercopidae, del orden Homoptera. En Costa Rica los pastizales de regiones altas formadas en su mayoría por pasto Kikuyo (Pennisetum clandestinum) son atacados por Prosapia distanti Lall. y talvez este es el insecto de mayor importancia económica por su aparente predominancia en las poblaciones presentes y su amplia distribución. Desde el punto de vista económico, cuando ocurre un ataque fuerte del insecto en pasto Kikuyo los daños producidos dan como resultado el deterioro completo del pasto. La presente investigación se realizó en la finca Evangelina, propiedad del señor Francisco Callejas situada a 16 km al N.O. de Turrialba y a 1440 m.s.n.m. Los objetivos de este trabajo fueron: a) Determinar la efectividad de Metarrhizium anisopliae, Bacillus thuringiensis y Beauveria bassiana como insecticidas microbiológicos. b) Determinar en que forma M. anisopliae es más efectivo, si en forma de espora o en forma de micelio. c) Determinar el efecto residual de los tratamientos. El diseño experimental fue bloques al azar con 6 tratamientos y 4 repeticiones y dos subtratamientos en parcelas divididas. La parcela total era un cuadrado 6x6 m y la efectiva 5x5 m. Los subtratamientos son: a) pasto sin recortar y b) pasto recortado a una altura de 5 cm sobre la superficie del suelo. La dosis por Ha de los tratamientos aplicados fue: - 30 litros de cultivo saturado de B. thuringiensis var. kurstaki HD-1 incubado por 72 h. - 30 litros de cultivo saturado de M. anisopliae en forma de micelio incubado por 72 h. - 9x10 sub exponente 12 esporas de M. anisopliae en suspensión acuosa. - 1 kg de Biotrol FBB (B. bassiana) 1 x10 sub exponente 9 esporas por gramo. - 20 kg de meta-systox granulado. - 500 litros de agua en el testigo. Se concluyó que el manejo o sea recorte del pasto, es la mejor forma para reducir la población ninfal y que ninguno de los tratamientos biológicos y químicos resultó efectivo en la lucha contra esta plaga.

Controlled environment studies of Pennisetum clandestinum showed that at 10 degrees C stamens of the male-fertile strain were not exserted from the floret although stigmas emerged normally. At higher temperatures both stamens and stigmas were exserted. Pollen abortion was high at 10 degrees C and was increased by lengthening photoperiod. Flowering of the male-sterile strain was not changed by any temperature or photoperiod. These responses to temperature may explain the natural sterility during the cool season.

Kikuio grass (Pennisetum clandestinum Hochst) is beyond any doubt, a pasture very important for farm animals; since its chemical composition is very similar to that of alfalfa, the present field trial was carried out; a randomized block design with 8 treatments was selected as follows: 1 N - P - K - Ca - Mg (complete manuring) 2 N - P - K - Ca----- (without Mg) 3 N - P - K-------Mg (without Ca) 4 ----P - K - Ca - Mg (without N) 5 N------K - Ca Mg (without P) 6 N - P - Ca - Mg (without K) 7 organic matter (without mineral fertilizers) 8 control Nitrogen was applied as NaN03 (topdressed) and as ammonium sulfate; P2O5 was given as superphosphate associated to bonemeal; K2O was applied as muriate, CaO as "sambaquis" (oyster shells); MgO was given as MgSO4 (topdressed). The source of organic matter was farmyard manure. As far yields are concerned the following observations were made: 1. treatment n. 7 was superior to all others; 2. considering the mineral fertilizers, good responses were due to N and P2O5; 3. the control yield was exceedingly poor, being inferior to all the others treatments; The chemical analyses revealed that: 1. the protein content decreased accordingly to this order: 7, 6, 5 and 1; treatment 4 (without N) gave the lowest protein content; 2. treatment n. 4 produced the highest fat content; treatment no. 7 ranked second; no. 8 gave the lowest fat content; 3. crude fiber: highest - treatment 7; lowest - 8; 4. ashes: the ashes content was higher in treatment 5; proprobably because the most abundant element in the ashes is K, the ash content of treatment 6 (no K) was very low; 5. non nitrogenous substances (determined by difference) - high in treatment 8 and low in treatment 7; 6. mineral elements in the ashes - the element omitted from a given treatment was very low in the grasses therein obtained; this shows the relative poverty of the soil in that element. As general remark the Authors suggest the use of farmyard manure in the fertilization of Kikuio grass; farmyard manure could probably substitute wither green manure or compost.

Se determinó el efecto de la fertilización y el encalamiento en la composición botánica y rendimiento de 2 mezclas de gramíneas y leguminosas. Los ensayos se establecieron en el Centro de Investigaciones Tibaitatá (Cundinamarca). En uno se sembró kikuyo y trébol blanco y en el otro, raigrás y trébol blanco. El sitio donde se localizaron los ensayos estuvo ocupado mucho tiempo por kikuyo y posteriormente por algunas siembras de papa y trigo. Después de arar el suelo e inmediatamente antes de la siembra, se incorporó la cal y los fertilizantes. El kikuyo se sembró por estolones y el trébol al voleo. En el segundo ensayo, el raigrás y el trébol se sembraron al voleo, con una densidad de siembra de 10 y 3 kg/ha, respectivamente. Se efectuaron observaciones durante 3 años, hasta completar 19 cortes en el ensayo con kikuyo y 22 en el ensayo con raigrás. La población de trébol fué mayor en la mezcla con kikuyo. El crecimiento y la competencia del raigrás no dejaron establecerse a la leguminosa, por lo que hubo que resembrarla. La cal y el K tendieron a aumentar la población de trébol, sucediendo lo contrario con el N. En el primer año no se observó ningún efecto de los fertilizantes y luego, el aumento no fué sobresaliente. Se puede deducir que las reservas de nutrientes en suelos de clima frío, después de cultivos abonados adecuadamente, podría mantener buen rendimiento y establecimiento de mezclas de pastos por un período de 2-3 años, siempre que haya disponibilidad de agua. Pastos y forrajes

Pennisetum clandestinum Hochst. is a vigorous fast growing grass introduced into sub-tropical areas of the United States from tropical Africa in approximately 1920. It has been used for soil erosion control and turf to a limited extent in California. However, in many places it has become a serious weed.

Nutrient deficiencies of old kikuyu (Pennisetum clandestinum Hochst.) and paspalum (Paspalum dilatatum Poir.) pastures on a krasnozem on basalt at Maleny, Queensland, were investigated. On the establishment of white clover (Trifolium repens L.), significant responses to phosphorus, potassium, molybdenum, and lime were recorded ; where clover did not establish well, as in the kikuyu sward, the overriding deficiency appeared to be nitrogen. Maximum response to phosphorus, as NaH2PO4, was achieved at a rate equivalent to 10 cwt superphosphate an acre. However, soil equilibrium potentialSP values and pot results with Ca(H2PO4), suggested a maximum near 20 cwt an acre might have been expected. An initial molybdenum application of 1 oz an acre was adequate : the main effect of lime was to release molybdenum in this acid soil (pH 4.6 in M/100 CaCl2). Aluminium and manganese were not toxic ; nevertheless, lime increased the yield and nitrogen content of clover grown in pots, possibly due to preferential nodule formation by the introduced rather than the 'native' rhizobia at the higher soil pH.

A nursery of single species and simple mixtures of 12 grasses and 9 legumes at Beerwah on the coastal lowlands of southern Queensland was grazed by sheep for over 16 years. For the last eight years 25.8 wethers a hectare (10.5/acre) were carried and thrived, heavy grazing pressure being maintained. Changes in botanical composition were recorded. The final mixture was dominated by Trifolium repens and Paspalm notatum. Other species to survive were Digitaria decumbens, Pennisetum clandestinum, Paspalum wettsteinii, and Brachiaria mutica. The majority of species failed to survive the close intense grazing by sheep. Annual replacements of phosphorus, sulphur, calcium, and potassium were made but nitrogen was never applied, and the highly productive pasture was maintained by legume nitrogen, mainly from white clover. Soil fertility improved under the pasture.

Pangola (Digitaria decumbens), kikuyu (Pennisetum clandestinum), setaria (Setaria sphacelata), and buffel grasses (Cenchrus ciliaris) were cut at different stages of growth and artificially dried to provide ten feeds with a range of leaf percentages (13-56), nitrogen contents (0.42-3.70 per cent), and acid detergent fibre percentage (26.3-43.3). Half of each cut was chaffed and the remainder pelleted. Both pellets and chaff were fed to Merino wethers in metabolism cages. Pelleting decreased the mean digestibility of dry matter by 6.8 percentage units, nitrogen by 2.2 percentage units, and ADF by 11.5 percentage units. Pelleting increased the mean voluntary intake by sheep 47 per cent for dry matter and 27 per cent for digestible dry matter with only minor differences in response to pelleting mature and young grass. The smallest increase from pelleting was 4.1 per cent for buffel grass containing 0.42 per cent N. In grass of the same age in which the nitrogen content had been increased to 0.75 by fertilizer nitrogen, pelleting increased intake by 26.6 per cent. It was concluded that with mature tropical grasses the response to pelleting may be limited by a low nitrogen content. Pelleting may be a useful technique for eliminating the effect of physical structure when studying factors affecting the voluntary intake of pasture plants.

Chloris gayana, Digitaria decumbens, Panicum maximum, Pennisetum clandestinum, and Setaria splendida were each cut at three stages of growth, dried, chaffed, and separated into "leaf" and "stem" fractions using a gravity separator. The mean purity of the leaf and stem fractions were 78 and 93%. Each fraction was fed to eight sheep to determine voluntary intake and dry matter digestibility. Mean voluntary intake of leaf was 46% higher than that of stem (57.7 v. 39.6 g/kg0.75), despite a slightly lower dry matter digestibility of the leaf fraction (52.6 v. 55.8%). The higher intake of the leaf fraction was associated (r =0.74, P< 0.01) with a shorter retention time of dry matter in the reticulo-rumen (mean 23.8 v. 31.8 hr), which appeared to be caused by the large surface of the leaf fraction initially available to bacterial degradation (mean 128 v. 41 sq cm/g). Ground leaf and stem samples showed no difference in rate of digestion in vitro since structural differences had been destroyed. The energy required to grind 1 g sample in a laboratory mill was less for leaf than stem (mean 234 v. 411 J/g) with a significant correlation between voluntary intake and grinding energy (r = –0.81). In the past a high voluntary intake has been attributed to a high bulk density, but in this study bulk density of the stem fraction was three times that of the leaf fraction and negatively correlated with voluntary intake (r = –0.70, P< 0,001). It was concluded that different plant fractions may be eaten in different quantities, despite similar dry matter digestibilities, and that in any study of the voluntary intake of roughages it is necessary to determine physical properties of the feed in addition to chemical composition.

The results of 45 sheep feeding experiments with kikuyu (Pennisetum clandestinum) based pastures are summarized. Mean values and the range of values for crude protein and normal acid fibre contents, dry matter, organic matter, and crude protein digestibilities and intake per kg liveweight0.75 are presented for the following pasture types : kikuyu, kikuyu plus nitrogenous fertilizer, Glycine wightii/kikuyu, Desmodium uncinatum/kikuyu and Vicia sativa/kikuyu. The relation between crude protein (CP) and crude protein digestibility, and CP and digestible crude protein for these five pasture types was established. Significant differences between pasture types are shown to exist and the importance of these differences discussed. A possible reason for differences in the relations found by previous workers is discussed.

Gibberellic acid (GA3 at 40 g/ha equivalent was applied to simulated swards of Pennisetum clandestinum (kikuyu grass) at the fourth leaf stage in a glasshouse held at a 25°C maximum and 15° minimum diurnal temperature cycle. Continuous 24-hr recordings of apparent photosynthesis and dark respiration in relation to normal variation in solar radiation were made on the whole swards by using an open chamber system monitored by infrared gas analysis. No effect was noted until 9 days from spraying, by which time the GA3 application stimulated the apparent photosynthetic rate of the sward and reduced the dark respiration rate. These effects became greater with time. The stimulation of apparent photosynthesis increased as the level of radiation increased. At 21 days from spraying, while large increases in apparent photosynthesis and reductions in dark respiration rate were being recorded, a botanical separation of the swards was made. GA3 increased the total dry weight (tops plus roots) of the sward and the dry matter above soil level. The latter effect was due to a greater amount of stem dry matter in the GA3-treated sward. GA3 reduced the dry weight of senescent leaf blade and leaf sheath tissue. GA3 had no effect on leaf area index. Area per leaf was increased, but GA3 stimulated apical dominance reduced the number of leaves per sq metre of sward. It is postulated that stimulation of apparent photosynthesis by GA3 is related to leaf age and a change in canopy structure through an improvement in leaf dispersion.

The literature on the flowering of kikuyu grass (Pennisetum clandestinum Hochst. ex Chiov.) is summarized. It is shown to be probable that some very vigorous strains are genetically male-sterile. An experiment is described in which flower initiation was caused by repeated defoliation and decapitation of shoots. The control of flowering in kikuyu grass is compared with that in other plants in which removal of apical dominance allows the initiation of flower primordia on lateral branches. The importance of the utilization of the genetic potential of both hermaphrodite and male-sterile strains in any kikuyu grass breeding programme is stressed.

Nine tropical pasture grasses were grown in pots of a phosphate-deficient solodic soil with varying additions of phosphate. Growth responses and chemical composition of the plant tops were recorded, and from these, critical percentages of phosphorus were established. All species responded to phosphate addition. Under the conditions of this experiment Melinus minutiflora was the most responsive species and Pennisetum clandestinum the least responsive. Critical percentages of phosphorus in the tops of Melinus minutiflora, Cenchrus ciliaris, Paspalum dilatatum, Panicum maximum, Chloris gayana, Sorghum almum, Setaria anceps, Digitaria decumbens and Pennisetum clandestinum sampled at the immediate pre-flowering stage of growth were 0.18, 0.25, 0.25, 0.20, 0.22, 0.20, 0.21, 0.16, and 0.22% respectively of the dry matter. Phosphate applications decreased the concentration of plant potassium, had no significant effect on calcium, increased magnesium in most species, and in four species increased sodium. The increases in magnesium and sodium are considered to result in part from reduced potassium uptake and the plant's ability to preserve cation balance. Three species, C. gayana, P. maximum and D. decumbens, had relatively high concentrations of sodium (58, 46, and 46% of total cations respectively). In contrast S. anceps had a relatively high concentration of potassium (56 % of total cations) and low sodium (7%). Phosphate applications decreased the concentration of nitrogen, and had little effect on chloride.