bluuebunny/crossref_metadata_2025 huggingface dataset:
Dry Matter Accumulation and Tuber Sprouting in Yams (Dioscorea SPP)
Authors: Okoli Obinani O.
Published: October 2008

Dry matter produced and allocated to the tuber and aerial portions of yam plants (Dioscorea spp) were studied over 3 cropping seasons in the moist forest region of Nigeria, in an attempt to relate dry matter accumulation to vegetative maturity in the crop. The effect of duration of growth of yam on post-harvest dormancy was also studied. Cultivars differed both in the total amount and period of growth when most dry matter was accumulated. A higher proportion of dry matter was allocated to tubers in lower-yielding than in higher-yielding cultivars. It appears that a yam tuber is ‘mature’ almost as soon as it is formed.
Influence of Lime and Macronutrients on Flue-cured Tobacco in Malaysian Tropical Peat
Authors: Chew W. Y. , Joseph K. T. , Adam M. A. , Ramli K.
Published: October 2008

On unlimed Malaysian peat (pH 3.5), flue-cured tobacco produced negligible leaf yields and showed no response to urea. Liming up to pH 5.25 (32 t/ha lime) linearly increased leaf yield. Tobacco responded linearly without reduced leaf quality to 90 k/ha N at pH 4.01 (8 t/ha lime), but to 45 kg/ha N at pH 4.40–5.25 (16–32 t/ha lime), higher N rates at the respective liming levels producing leaves of lower quality. The optimum rates of P and K for flue-cured tobacco appeared to be 26 and 186 kg/ha respectively, with linear responses up to those rates.
Effects of Close Planting on Soyabean (Glycine Max) Cultivars in Malaysia
Authors: Chew W. Y. , Chew H. J. , Razak H. A. H. Abdul , Ariffin B. , Malek M. A.
Published: October 2008

Five field experiments studied the effects of high planting densities, ranging from 83,000 to 667,000 seeds/ha, on eleven soyabean cultivars. Germination rates ranging from 32 to 100% and averaging 76%, resulted in actual plant densities of 45,000 to 296,000 plants/ha. Bean yields of the four shortest and earliest-maturing (64–67 days) cvs (Wakashima, Shi-shi, Palmetto and Tai Tah Kaoh Siang 58) increased with increasing density, producing highest yields at the highest plant densities investigated (222,000–286,000/ha) but 7 taller cvs, maturing in 80–126 days (P2, C13, C21, P4, D5, T10 and C28), produced reduced yields with increasing density, the lowest densities investigated (45,000–83,000 plants/ha) giving the highest bean yields.
Effects of Intercropping on Yield and Returns in Corn and Sorghum
Authors: Reddy K. Anand , Reddy K. Raj , Reddy M. Devender
Published: October 2008

The yield and gross returns (Rs/ha) were studied over two years in three experiments on intercropping in corn and sorghum. Paired-row planting recorded 8 to 12% and 44% higher yield in corn and sorghum respectively over conventional equidistant planting at the same plant populations. Additional gross returns due to intercropping ranged from 24 to 76% in corn (1975–76 winter) and 4 to 56% in corn and 15 to 75% in sorghum (1976 rainy season) compared to pure crops. Intercropping was beneficial, particularly in the limited cropping periods of this semi-arid tropical zone.
Effects of No-Tillage and Ploughing on Roots of Maize and Leguminous Crops
Authors: Maurya P. R. , Lal R.
Published: October 2008

Root development of maize (Zea mays), soyabean (Glycine max), cowpea (Vigna unguiculata), and pigeonpea (Cajanus cajan) was investigated with and without tillage. Observations were made at different growth stages by digging trenches normal to the rows, by core sampling, and by observing growth of roots against glass windows. There were more maize roots in the surface layer (0–10 cm) with no-tillage than in conventionally ploughed plots, but at 10–40 cm maize roots were more abundant and soyabean and pigeonpea roots less so in the no-tillage plots.
Weed and Fertility Management in Rain-fed Maize
Authors: Guleria W. S. , Singh C. M.
Published: October 2008

A field experiment to study weed and fertility management in rain-fed maize was undertaken at the Palampur Experimental Farm during the wet seasons of 1977 and 1978. Intercropping soya-bean in maize did not impose undue competition and significantly increased net profit per ha. Yields and net returns were significantly higher when weeds were controlled and 80 kg N/ha was applied. Increased application of fertilizer without weed control did not alter the yield of maize, and there was no response to phosphorus. Various yield attributes of maize were significantly affected by weeding and nitrogen treatments through their effects on grain and stover.
Reciprocal Grafts between Large Plants: Technique and Evaluation with Cowpeas
Authors: Summerfield R. J. , Minchin F. R.
Published: October 2008

A technique has been developed and tested for successfully grafting large, leafy cowpea shoots onto roots, which may be nodulated or not. Grafting per se had no significant effect on either the production or distribution of vegetative or reproductive dry matter compared with control plants left intact throughout growth. Furthermore, numerical components of yield and the concentration (%) and content (mg) of nitrogen in respective plant components were remarkably invariant. Examples are discussed of the variations in nitrogen nutrition which can be achieved and the potentials of the technique in general.
Effects of Liming and Soil pH on Guinea Grass (Panicum maximum) in Malaysian Tropical Oligotrophic Peat
Authors: Chew W. Y. , Williams C. N. , Ismail L. , Ramli K.
Published: October 2008

In a three-year field experiment on acid peat (pH 3.47) up to 12 t/ha lime increased peat pH (0–30 cm depth) by 0.061/t. Annual guinea grass dry matter increased in quadratic relation with liming up to pH 4.20 (12 t/ha lime) but there was no difference between the cvs Sigor and Colonoa. Liming decreased the N, P and K, but increased the Ca and Mg contents of the harvested grass. Liming also increased the uptake of all five nutrients investigated, either linearly or curvilinearly.
Genotype × Environment Interactions on Grain Yield and other Characters of Soyabeans (Glycine max)
Authors: Funnah S. M. , Mak C.
Published: October 2008

Twenty soyabean genotypes, grown in 12 environments, showed significant g × e interactions for grain yield and most of the other traits. The g × s interactions were unimportant, but the g × 1 and g × 1 × s were of considerable magnitude for most traits. The experiments provided estimates of genotypic, environmental and genotype-environmental variance. The presence of a high environmental variance for grain yield suggested the possibility of raising yield levels through improved management practices.
Effects of Age on Celosia Cultivars
Authors: Omueti Olusola
Published: October 2008

Studies of the effects of age on yield components and nutrients status of Celosia argentea cultivars showed the highest crude protein content, total vitamin C and leaf/stem ratio in leaves harvested 5 to 7 weeks after sowing, but the highest total marketable and edible yields, as well as total crude protein, 15 weeks after sowing. The narrow-leaved local cultivar gave higher crude protein per cent and vitamin C than the broad-leaved one, but its yield of edible leaf was lower. Breeding potentials of the cultivars were highlighted.
Effects of Mulches on Soil Temperature and Growth of Tea Plants in Kenya
Authors: Othieno C. O. , Ahn P. M.
Published: October 2008

Five types of mulches (black plastic, stone chippings and three types of grass) and a control were used on young clonal tea plants following transplanting. Soil temperature differences were observed in the first two years but disappeared when the tea canopy had developed to cover over 40% or more of the soil surface. Stem diameter, yield (during the first two years) and total dry matter production were positively correlated with soil temperatures over the range 14–21°C. Beneficial effects of raising soil temperature by black plastic mulch were short-lived, but the detrimental effect of reducing temperature by grass mulches was more severe and long lasting. Grass mulches induced shallow rooting, as a result of which the tea was more susceptible to drought.
Effects of Mulches on Soil Water Content and Water Status of Tea Plants in Kenya
Authors: Othieno C. O.
Published: October 2008

Soil moisture content and plant water status of young clonal tea plants were affected differently by five different types of mulches (black plastic, stone chippings and three types of grass) when compared with a control without mulch. During prolonged droughts, soil moisture content was generally highest under Napier grass and black plastic but any type of mulch was better than no mulch in conserving moisture to 90 cm depth. Tensiometer data at the onset of rains after an unusual prolonged dry season suggest that the infiltration was fastest under grass mulches. After four years of continuous application grass mulches had significantly most effect on water holding capacity, but induced shallow rooting systems, which made the mulched tea more susceptible to drought.
Effects of Combined Nitrogen on Nodulation and Growth of Phaseolus vulgaris
Authors: Awonaike K. O. , Lea P. J. , Day J. M. , Roughley R. J. , Miflin B. J.
Published: October 2008

The effect of Rhizobium strain and low levels of nitrogen on growth and nitrogen fixation was studied on 5 seedlines of Phaseolus vulgaris. All plants responded to irrigation when low levels of nitrogen were supplied throughout each experiment during vegetative growth, but the final seed yield was not significantly affected. All strains induced less nodule tissue and lower nitrogenase activity per plant when nitrogen was applied; some strains were less sensitive than others. The proportion of the plant's nitrogen estimated to be derived from fixation (based on acetylene reduction) and fertilizer was affected by host genetics. Nodulated plants had nitrogenase activities comparable with other grain legumes and responded to combined nitrogen during vegetative growth, but this was not reflected in grain yield.
Effects of Plant Density on Ear Barrenness in Maize
Authors: Iremiren G. O. , Milbourn G. M.
Published: October 2008

Increasing plant density in maize from 8 to 32 plants/m2, without irrigation, had little effect on the time of ear primordia differentiation but delayed the time of silking (by up to 16 days), reduced the potential grain sites available for pollination and the number of grains pollinated, and increased grain abortion during the grain fill period. In cv LG11 sufficient fertile ears were retained to maintain grain yield throughout the wide range in density, whereas yield fell in Anjou 210 due to barrenness after silking, which was the major factor responsible for the intolerance of this variety to high density. However, in a variety such as Anjou 210, which has a tendency to barrenness under stress, the grain content of the end product would not be affected at the plant densities normally used for maize silage.
Dry Matter Production and Partition in Relation to Yield of Tea
Authors: Magambo M. J. S. , Cannell M. G. R.
Published: October 2008

Tea yields of 1 to 4 t ha−1y−1 of dry shoot tips are much less than those of other vegetative crops like grasslands or forests growing in similar conditions, partly because plucking restricts tea biomass production, but mainly because the harvest index of tea is small. In Kenya, plucked tea produced 36% less biomass per hectare per year than unplucked tea, and 64% less wood. Only 8·3% of the total annual biomass increment was harvested. This proportion might be increased by plucking older leaves, increasing the shoot:root ratio, and by lowering the plucking table so that less wood was produced.
Comparisons between Press and Pressure Chamber Techniques for Measuring Leaf Water Potential
Authors: Yegappan T. M. , Mainstone B. J.
Published: October 2008

A hydraulic press (the J-14) was compared with a Scholander pressure chamber to measure leaf water potential in Theobroma cacao, Gliricidia maculata, Cajanus cajan and Elaeis guineensis. Although the press satisfactorily estimated water status in soft, unhardened leaves of T. cacao, G. maculata and C. cajan at high water potential, it underestimated water status in hardened leaves of T. cacao. Satisfactory estimates were obtained at low water potential for hardened leaves of T. cacao but not for the others. There was a poor relation between readings of the two instruments for E. guineensis over a wide range of water potentials because press readings appeared to be influenced by leaf structure.
Effects of Harvesting Frequency on Leaf and Root Yields of Cassava
Authors: Dahniya M. T. , Oputa C. O. , Hahn S. K.
Published: October 2008

Total fresh leaf yield of cassava (Manihot esculenta Crantz) variety Isunikankiyan was not significantly affected by harvesting frequency, unlike variety TMS 30211. Compared with plants whose leaves were not harvested, there was a decrease in total fresh tuberous root yields of 56–76%, 34–62% and 15–32% when leaves were harvested at 1-, 2- and 3-month intervals respectively. The two cassava varieties reacted differently to leaf harvests in terms of tuber yields. Harvesting the top leaves of cassava at 2- or 3-month intervals is recommended to ensure reasonable yields of both leaves and tuberous roots.
Effects of Planting Patterns and Population on Water Relations of Maize
Authors: Babalola O. , Oputa C.
Published: October 2008

Seven plant populations, ranging from 24,000 to 73,000 plants/ha of the maize variety White Composite, were established in four growing seasons between 1976 and 1978 by varying row width and number of plants per hill. Soil water profiles, leaf and soil water potentials, and leaf resistances were monitored. The results indicated a close link between these parameters, number of plants per hill and overall plant populations. Grain yield increased with increasing plant populations during the early growing season but dropped beyond 54,000 plant/ha (spaced two plants per hill at 60x60 cm) during the late season, due to adverse plant water status.
Effects of Irrigation Schedules on Yield of Mustard (Brassica Juncea)
Authors: Prihar S. S. , Sandhu K. S. , Khera K. L. , Sandhu B. S.
Published: October 2008

In a 3-year field study with mustard (Brassica juncea L.) on deep well-drained sandy loam and loamy sand soils, 11 post-sowing irrigation schedules based on pan evaporation and growth stages were compared. One irrigation three weeks after sowing gave maximum grain yield and water use efficiency, increasing yield 40% in 1973–74 and 30% in 1976–77 compared with no irrigation. The total water use in this treatment averaged 31·2 cm, of which 15·8 cm was extracted from the 0–180 cm soil profile. Use of soil water by the crop decreased with the amount of post-sowing irrigation. More than one post-sowing irrigation tended to decrease yield and water use efficiency.
Border Effects and Optimum Plot Sizes for Climbing Beans (phaseolus vulgaris) and Maize in Association and Monoculture
Authors: Davis J. H. C. , AmÉZQuita M. C. , MuÑOZ J. E.
Published: October 2008

Minimal competition was observed between adjacent plots of climbing bean varieties and maize in association, but there was a large head border effect which was not uniform among varieties. Head borders of 1 m at each end of the plot are recommended and a net plot size of 11 m2 with 3 replications for climbing bean varieties associated with maize was found to be adequate to detect significant differences in yield of beans of 24% of the mean. For climbing beans in monoculture a somewhat smaller plot (8 m2) would achieve the same level of precision. Larger plot sizes in general were needed for maize comparisons, especially in association.
Comparisons of the Performance of Sugar-cane Varieties in Trials and in Agriculture
Authors: Walker D. I. T. , Simmonds N. W.
Published: October 2008

Twelve varieties of sugar-cane grown in Barbados, West Indies, during the past 40 years are compared with respect to cane yield performance in trials and in agriculture. Comparisons are based on data-pairs matched for site, season and crop, using both means and variety-on-variety regressions. Conclusions are that: trials greatly over-estimate mean agricultural differences between varieties; variety-on-variety regressions reveal numerous GE effects and account for much variance, but agree poorly as between trials and agriculture and are not useful in improving prediction; in view of the universal use of trials for prediction and decision-making, it is a matter of some practical importance that their validity should be tested in other crops.
Criteria for Scheduling the Irrigation of wheat
Authors: Misra R. D. , Pant P. C.
Published: October 2008

A field experiment evaluating criteria for scheduling wheat irrigation was conducted from 1975 to 1977 in a sandy loam soil with treatments scheduled according to physiological stages, soil moisture conditions, pan evaporation and leaf water potential. Grain and straw yields, spikes/m, fertile spikelets/spike and number and weight of grains/spike were significantly influenced by treatments. Irrigation based on leaf water potential was as good as when based on physiological stages or soil moisture, and the use of pan evaporation was no better than other methods of scheduling.
Yield Increases in Summer Cereal Crops in Israeli Fields Inoculated with Azospirillum
Authors: Kapulnik Y. , Sarig S. , Nur I. , Okon Y. , Kigel J. , Henis Y.
Published: October 2008

InoculatingZea mays(three cultivars),Sorghum bicolor, Panicum miliaceumandSetaria italicawith nitrogen-fixing bacteria of the genus Azospirillum in Northern Negev and Bet Shean Valley field experiments resulted in significant increases in yield of grain and foliage of commercial value. It was concluded that inoculating summer cereal crops in Israel may save valuable nitrogen fertilizer.
Heat-induced Sterility in Cotton Sown During Early April in West Punjab
Authors: Taha M. A. , Malik M. N. A. , Chaudhry F. I. , Makhdum M. I.
Published: October 2008

An experiment was conducted during the 1978/79 summer at the Central Cotton Research Institute, Multan-Pakistan to evaluate the crop production patterns of two cultivars of cotton (G. hirsutum L.) differing in their reaction to heat-induced sterility. Boll set in variety ST3 amounted to 7.7% of the total fruiting points, from flowers opening during the hottest months of June, July and early August, while almost all the fruiting points produced by cultivar B557 during the same period were shed and no bolls were set. Of the flowers examined during July, 83.3% in B557 contained non-dehiscent anthers against 6.7% in ST3.
Variability for Seedling Vigour in Maize
Authors: Fakorede M. A. B. , Ojo D. K.
Published: October 2008

Considerable variation in seedling vigour was observed among 36 maize populations; genotypic variances were generally high for emergence percentage (E%), emergence index (EI), dry-matter accumulation and relative growth rate (RGR). Broadsense heritability values and environmental variances indicated that E% and EI would be more reliable indices for seedling vigour than emergence rate index (ERI). The expression of growth rate (GR) was influenced more by the environment than the genetic constitution of seedlings; GR was not therefore an effective indicator for seedling vigour, and RGR would be preferred because it was more heritable and less influenced by the environment.
Growth, Development and Grain Yield of Maize
Authors: Hawkins R. C. , Cooper P. J. M.
Published: October 2008

Results from field experiments showed that number of mature grains per plant was related to the plant growth rate during the pre-flowering period. This relation was further improved when growth rate was expressed relative to the rate of plant development. This evidence supports the theory that grain abortion is linked with assimilate production.
Variation in Growth Among 13 Prosopis (mesquite) Species
Authors: Felker Peter , Cannell G. H. , Clark Peter R.
Published: October 2008

Mesquite (Prosopis spp) is a nitrogen-fixing and drought-resistant leguminous tree which exists in many of the semi-arid regions of the world but little has been done to develop its potential for wood, nitrogen fixation or pod yield. We report field and greenhouse cultural practices for mesquite and the results of a field screening trial for biomass production of 32 accessions, representing North and South American and African germplasm. Non-destructive biomass estimates, derived from height and stem diameter measurements, had a 180-fold range; the preponderance of slow-growing accessions were from the rangelands of southwestern USA.
A Field Technique for Separating Above- and Below-Ground Interactions in Intercropping: an Experiment With Pearl Millet/Groundnut
Authors: Willey R. W. , Reddy M. S.
Published: October 2008

A field technique is described in which trenches were dug and vertical polythene partitions installed to eliminate below-ground interactions between component crops in intercropping. With pearl millet/groundnut the control intercrop (i.e. not dug out) gave a yield advantage of 22% compared with sole cropping. A treatment dug out but refilled without polythene partitions was very similar to the control intercrop, indicating that the digging procedure per se had little effect on growth. An intercrop treatment in which below-ground partitions were installed gave a yield advantage of 19% over sole cropping, suggesting that the main determinant of yield advantage was an above-ground interaction between the canopies. However, partitioning decreased millet yield and increased groundnut yield, indicating that below-ground interactions were important in determining the competitive balance of the two crops. It is concluded that the partitioning technique is promising.
Nitrogen Application for Short-Term Forages in Saudi Arabia. I. Winter Annuals: Wheat, Oats and Italian Ryegrass
Authors: Bartholomew P. W. , Williams R. J.
Published: October 2008

Nitrogen fertilizer requirements and potential forage yield of wheat, oats and Italian ryegrass grown under irrigation in Saudi Arabia were assessed. Mexipak wheat produced high DM yields with between 100 and 150 kg/ha N, and the mode of nitrogen application did not significantly affect DM outputs. Nitrogen at 150 kg/ha produced highest DM yields for oats, although the application of 50% of irrigation requirement as drainage water reduced yield by 8%. Italian ryegrass produced a mean yield of 14.6 t/ha in 169 days with a nitrogen application of 60 kg/ha; direct drilled on a field scale it yielded 8.76 t/DM/ha with a total application of 270 kg N/ha.
Nitrogen Application for Short-Term Forages in Saudi Arabia. II. Summer Annuals: Maize, Proso Millet and Foxtail Millet
Authors: Bartholomew P. W. , Williams R. J.
Published: October 2008

Nitrogen fertilizer requirements and potential forage yield of maize and two millet types grown under irrigation in Saudi Arabia were assessed. Nitrogen application at 50 kg/ha produced mean yields of up to 15.7 t/ha in maize variety Pioneer H.3147. Splitting the nitrogen application did not significantly affect yield. Nitrogen above 100 kg/ha did not significantly increase DM yield of Proso millet (Panicum miliaceum). Mean total DM yields of 17.6 t/ha of Setaria italica were produced, after 111 days, with 150–200 kg/ha of nitrogen; 150 kg/ha of P2O5 produced a mean DM yield 7.9% higher than 75 kg P2O5/ha.
Intensive Forage Production in Northern Mexico. I. Responses Of Italian Ryegrass to Nitrogen and Irrigation
Authors: Thomas N. , Farias J. M.
Published: October 2008

The response of Italian ryegrass (IRG) to nitrogen fertilization, irrigation frequency and harvest interval indicated that management of nitrogen and water is the determinant of productivity under semi-arid northern Mexican conditions. Where water is non-limiting the effects of harvest interval can be eliminated. A soil moisture balance model indicated the inadvisability of seeding IRG in sandy soils if water is a scarce resource because of the high frequency of irrigation that would be required. The seeding (September) and late production (April) periods were identified as critical in regard to irrigation need and limiting in terms of the area that it would be possible to seed.
Early Exploitation of Hevea Rubber Trees by Puncture and Short-Cut Tappings
Authors: Waidyanatha U. P. de S. , Angammana D. K.
Published: October 2008

Puncture tapping and one-eighth spiral (S/8) tapping, both combined with Ethrel stimulation, were compared with conventional half spiral (S/2) tapping of immature Hevea trees. Stimulated puncture-tapped trees in some experiments yielded more rubber and had much more sucrose in the latex than unstimulated half-spiral tapped trees. Yields of puncture-tapped trees also increased with increase in the quantity of Ethrel and the number of punctures, but were not affected by the size of puncture. Girth increments of the trees and percentage dry rubber content of the latex were approximately equivalent in all three methods of tapping.
Intercropping Pigeonpea to Conserve Fertilizer Nitrogen in Maize and Produce Residual Effects On Sugarcane
Authors: Yadav R. L.
Published: October 2008

Field experiments were conducted for 3 years covering 4 crop seasons at Lucknow to study the utility of pigeonpea (Cajanus cajan) as an intercrop in economizing N for maize (Zea mays) and to assess the residual fertility of kharif crops on autumn-planted sugarcane (Saccharum officinarum). Pigeonpea increased the soil N content due to substantial nodulation, but as an intercrop it did not increase the yield of maize at any level of nitrogen. Sugarcane grown after pigeonpea yielded 43% more than when grown after maize. Intercropping pigeonpea in maize would be more beneficial than growing a pure crop of maize before planting sugarcane.
Effects of Patterns and Methods of Sowing on Sorghum/Striga Relations
Authors: Bebawi F. F. , Farah A. F.
Published: October 2008

Changing the geometry of planting under irrigated conditions from the traditional pattern of regular rows (with plants equidistant from each other) into double rows (with plants arranged in row pairs) promoted plant competition. This resulted in a significant reduction in overall yield components of sorghum but a marked increase in shoot yields of striga. A better yield of sorghum was obtained in ridged plots than in flat plots, associated with less striga infestation and a slightly higher soil moisture content under the ridged plots.
Controlled Environments as an Adjunct to Field Research on Lentils (Lens culinaris) I. Perspectives, Tenets and Objectives
Authors: Summerfield R. J. , Muehlbauer F. J.
Published: October 2008

Our experience with potentially tropic-adapted grain legumes leads us to hypothesize that ‘with appropriate and sufficiently proven technology, developed specifically for the purpose, controlled environment facilities can be a powerful adjunct to field research and so assist in the attainment of crop improvement objectives in lentils’. This contribution comments on the ‘adaptation’ of grain legume crops to their environments, describes current lentil production in the USA and elsewhere, and discusses the tenets and objectives of a programme of research devoted to the ultimate release of lentil genotypes that are well adapted to the environments for which they are intended.
Effects of Ground Rock Phosphate and Elemental S on Yield and P Uptake of Maize in Western Kenya
Authors: Bromfield A. R. , Hancock I. R. , Debenham D. F.
Published: October 2008

The effect on maize yields of ground rock phosphate, alone or mixed with sulphur in either of two proportions, and of single-superphosphate, was measured at five consecutive harvests. At the first harvest single-superphosphate increased yield by 1.54 t and the best of the mixtures by 0.56 t grain/ha. Ground rock phosphate alone had no effect on yield. At the third harvest there were no yield differences between sources; because yields produced by rock phosphate and the mixtures improved. The cumulative increase in yield produced by single-superphosphate was 3.58 t/ha and by rock phosphate 2.69 t grain/ha, but because the fertilizer cost ratio was 3:1, additional grain produced by rock phosphate cost half as much. The apparent P recovery ranged from 5.40 to 8.28 kg/ha, with most from single-superphosphate and least from the mixture containing most elemental-S.
Boron Nutrition of Amazon Cocoa (Cacao theobroma) in Nigeria. I. Early Results of Fertilizer Trials
Authors: Ojeniyi S. O. , Egbe N. E. , Omotosho T. I.
Published: October 2008

Boron treatment was superimposed on half of 48 Amazon cocoa NK-treated plots in four locations across Southern Nigeria. Boron was deficient in soil and leaves of untreated 12-year-old Amazon cocoa, but boron treatment increased bean yield from 13 to 70%. Application of N and K fertilizers reduced the impact of soil-applied boron.
Influence of Flooding and Soil Moisture Content on Elongation of Sugar cane in Trinidad
Authors: Gumbs F. A. , Simpson L. A.
Published: October 2008

The total growth increment of sugar cane stalks from 13 to 22 weeks after planting was 55% greater in elevated than depressed areas in fields flooded intermittently during the period of measurement. The weekly growth increments were 137–9% greater in elevated than depressed areas, especially when soil moisture was high. The cane was on top of high ridges but water stood up to 10 cm deep over the top of the ridges in depressed areas for up to 5 or 6 days after rain and at varying depths below the top for several more days. Provided the soil was not submerged, tillers elongated most when the soil profile was saturated or nearly so; mere waterlogging without submergence seems not to damage cane. Tiller elongation and soil moisture were well correlated regardless of depth of sampling between 0 and 45 cm, but different relations were obtained for elevated drained areas and depressed areas subject to submergence.
Effects of Nitrophoska and Atrazine on relations betweenSorghum bicolorandStriga hermonthica
Authors: Bebawi F. F. , Farah A. F.
Published: October 2008

Nitrogen-atrazine combinations were significantly more effective in stimulating higher yield components of sorghum and depressing yield components of striga than sole treatments of either nitrogen or atrazine. Over all treatments nitrophoska at 129 kg N/ha in combination with atrazine at 1.75 kg/ha gave 224, 180, 155 and 151% increases in yield components over the control for head, straw, 1000 grain weights and plant height of sorghum, and a decrease in 83, 88 and 90% of striga density at 8, 12, and 16 weeks from sowing the sorghum. The synergistic effect of nitrogen-atrazine is demonstrated.
Designing Experiments for Intercropping Research
Authors: Mead R. , Stern R. D.
Published: October 2008

The efficiency of many intercropping research programmes could be improved if research workers made fuller use of modern statistical knowledge about experimental design. Important statistical considerations for experimental design and plot sampling are reviewed and their relevance to intercropping research assessed. The general philosophy of factorial structure and blocking, and specific ideas on the use of systematic designs and monocrop plots, are discussed.
Phenology of Chickpeas (Cicer Arietinum) in Contrasting Aerial Environments
Authors: Roberts E. H. , Summerfield R. J. , Minchin F. R. , Hadley P.
Published: October 2008

Effectively nodulated plants of 3 cultivars of chickpea, classified as early, mid-late and late-maturing, were grown to reproductive maturity in 12 factorial combinations of simulated tropical environments in growth cabinets. Cultivars varied in sensitivity but all responded as quantitative long-day plants and flowered earlier in longer photoperiods. Differences in temperature had important consequences, especially on the duration of the reproductive phase and overall crop longevity; they also induced plants to flower at the same time in different photo-periods. Early flowering plants did not necessarily mature early; others taking twice as long to come into flower had short reproductive periods and came to maturity at the same time. Relations between phenology, morphology and seed yield are described and compared with similar data for field-grown plants. Screening for ‘adaptation to environment’ in chickpeas is discussed.
Effects of Single-crop Agri-silviculture on Soil Analysis
Authors: Ojeniyi S. O. , Agbede O. O.
Published: October 2008

Experiments were carried out to examine the effects of agri-silviculture in three different ecological zones of Southern Nigeria. The four treatments considered were Gmelina arborea (forest tree crop) alone, Gmelina + maize, Gmelina + yam, and Gmelina + cassava, each treatment being replicated 8 times in each location. Composite soil samples, collected from two surface layers of each treatment plot, were analysed. Inter-planting young forest plantations with food crops usually increased soil N and P, at the slight expense of soil organic carbon. However, exchangeable Ca, Mg and K contents, pH, and soil N and P contents, were not statistically different among the treatment plots.
Growth and Resource Use of Maize, Pigeonpea and Maize/Pigeonpea Intercrop in an Operational Research Watershed
Authors: Sivakumar M. V. K. , Virmani S. M.
Published: October 2008

Growth and interception of Photosynthetically Active Radiation (PAR) in a maize/pigeonpea intercrop and sole maize and sole pigeonpea crops grown in large plots in an operational research watershed at ICRISAT research centre were compared. Growth and yield of the maize crop, in pure stands and in intercrop, were not significantly different. Efficiency of dry matter production, calculated from the relations between dry matter production and cumulative intercepted PAR, was highest for the maize/pigeonpea intercrop, followed by sole maize and sole pigeon-pea, proving the utility of such intercrops in making better use of resources in the Semi-Arid Tropics (SAT).
Effects of Plant and Canopy Density on Seed Yield and Oil Content in White Lupin (Lupinus albus)
Authors: McGibbon R. , Williams Watkin
Published: October 2008

High plant populations caused a reduction in pod set and consequently in seed yield. Removal of axillary branches reduced the average weight of seed and percentage seed oil on primary racemes, indicating transport of photosynthate from branch leaves to storage sites in pods on primary racemes. Debranching at low densities was also associated with premature senescence of leaves and desiccation of immature pods, suggesting that branch removal need not have an exclusively simple nutritional basis. High canopy density reduced oil content, and seeds borne on primary racemes had lower oil levels than those on axillary branches.
Fertilizer Response of Napier Grass under Different Soil Conditions in Brunei
Authors: Williams C. N.
Published: October 2008

Seasonal fertilizer response of napier grass (Pennisetum purpureum) was measured on various soils in Brunei. Climate was moderately humid over the three-year experimental period, with the longest dry spell about 4 months. Optimal fertilizer N levels (balanced with other nutrients) ranged from about 240 to 900 kg/ha/yr on the different soil types and under different moisture conditions. Dry forage yields at the optimum fertilizer levels ranged from 5 t/ha/yr on sandy soil under dry conditions, to 55 t/ha/yr on a sandy clay loam with adequate water. Moderate production of about 20 t/ha/yr was obtained on acid sulphate soil with fertilizer and lime. Digestible nutrient and protein levels of 60-day forage were about 55 and 10% respectively.
Effects of Temperature and Preflooding on Rice Yields in Kenya
Authors: Young L. H.
Published: October 2008

An investigation was made at the Mwea Irrigation Settlement, Kenya, to discover the reason why rice units which were transplanted earlier gave higher yields. Yields over an 11-year period were examined in relation to meteorological data and cultivation activities. It was found that the period during which the units were flooded prior to transplanting correlated with the date of transplanting, with longer preflooding periods causing higher yields and not the transplanting date. A yield/temperature relationship was also established.
Intercropped Corn–Soyabean Density Studies. I. Yield Complementarity
Authors: Putnam D. H. , Herbert S. J. , Vargas A.
Published: October 2008

Intercropped corn and soyabean were grown in a randomized block design (RBD) and a systematic design (SD) in 1981 and 1982 to evaluate total yield, yield complementarity, crop competition and land-use efficiency as affected by corn and soyabean densities. In the RBD, three corn density treatments were applied to corn–corn–soyabean–soyabean, corn–corn–soyabean, and corn–soyabean intercrop row patterns and to monocultures. In the SD, 9 or 10 corn densities were factorially combined with up to 13 soyabean densities in a corn–soyabean row pattern (91 cm spacing). In the RBD, total intercrop yields were similar to corn monoculture yields (60.8 to 62.7 t ha−1 in 1981) in the corn–corn–soyabean and corn–soyabean patterns at high corn densities but were less at low density. The corn–corn–soyabean–soyabean pattern yielded 87% of the corn monoculture at high density in 1982. These results were confirmed in the SD, where total intercrop yields were highly responsive to corn density and poorly responsive to soyabean densities. Both experiments indicated that high corn row densities are needed to maintain yields in corn–soyabean intercrops, possibly higher than the levels studied. Land equivalent ratios were above 1.0 for all but the low density corn–corn–soyabean–soyabean pattern in the RBD. The ability of an intercrop with as many as half the corn rows replaced by soyabean to produce yields similar to corn monoculture indicates a biological complementarity for dry matter production in the mixtures.
Influence of Seedbed Tilth on Emergence and Root and Shoot Growth of Seedlings of Some Crops
Authors: Malik R. S. , Jhorar B. S. , Dahiya I. S.
Published: October 2008

Wheat (Triticum aestivum), mustard (Brassica juncea), gram (Cicer arietinum) and barley (Hordeum vulgare) seedlings were raised in soils of different tilth created in microplots during 1981 and 1982. Amplitude in diurnal seed-zone temperature and soil moisture content increased with tilth coarseness. At low soil moisture levels, seedling emergence of wheat and mustard decreased with increasing clod size while that of gram and barley increased. These effects were not significant at high soil moisture levels. Shoot growth of all the crops was higher under coarse tilth than under fine tilth at both moisture levels. Root growth of wheat and mustard decreased with increasing clod size while that of gram and barley increased, at both moisture levels. Mustard had the highest seedling emergence at the low moisture level. Seedling emergence and shoot growth were higher under high moisture than under low moisture for all crops. Root growth varied depending upon the type of crop.
Evaluation of Fertilizer Placement Methods for White Yam (Dioscorea rotundata)
Authors: Nwinyi S. C. O. , Enwezor W. O.
Published: October 2008

Four fertilizer placement methods (ring, sideband, broadcast and furrow) applied ten weeks after planting were compared in nine experiments to determine the best method for fertiliza- tion of white yam (Dioscorea rotundata). Significant yield differences due to the treatments were observed at Mbato, Umudike and Igbariam in 1980 and at Nsukka and Igbariam in 1981. Best yields overall were obtained with the sideband method, followed by broadcast, ring and furrow in that order. However, man-days taken to fertilize one hectare by ring, sideband, furrow and broadcast methods were 11.2, 10.9, 2.8 and 1.5, respectively, so that in this regard, broadcast is preferable to the other placement methods.
Evolution of Grain Legumes. III. Pulses in the GenusVigna
Authors: Smartt J.
Published: October 2008

The genusVignaincludes seven species of pulse, two African and five Asian. While the Asian species are within the subgenusCeratotropis, the two African species are in different sections of the subgenusVigna, namelyCatjang(V. unguiculata) andVigna(V. subterranea). Limited gene flow is possible within subgenusCeratotropis, but none has as yet been demonstrated between subgenera nor between sections within subgenusVigna. Parallel evolutionary trends are apparent in all species, with considerable increase in seed and pod size. Erect bush forms have evolved in all cultigens exceptV. aconitifoliaandV. subterranea. The former has not apparently changed much in vegetative form under domestication, while the geocarpy of the latter precludes erect growth. Future prospects for the Asiatic grams would be better if yield levels could be improved. The cowpea is likely to remain an important crop at present levels of performance although there is room for improvement. There seems little immediate prospect of expanded ground bean production under existing conditions.
Soil Movement in Long-term Field Experiments as a Result of Cultivations I. A Model for Approximating Soil Movement in One Horizontal Dimension by Repeated Tillage
Authors: Sibbesen E. , Andersen C. E. , Andersen S. , Flensted-Jensen M.
Published: October 2008

A serious problem in long-term field experiments is that soil is moved from plot to plot as a result of cultivations. The problem is often overlooked and very few attempts have been made to quantify this movement under varying conditions.

A simple, mathematical model for approximating the movement of soil in one horizontal dimension by repeated tillage with one or more tillage implements is presented. The model describes the development with time of a concentration gradient of substance, by means of the solution of a diffusion equation. The model is in agreement with ‘the central limit theorem’, when it is used for the situation where the same cultivations are repeated many times in alternating directions.

The model fitted well to data taken from the literature.
Soil Movement in Long-term Field Experiments as a Result of Cultivations. II. How to Estimate the Two-Dimensional Movement of Substances Accumulating in the Soil
Authors: Sibbesen E. , Andersen C. E.
Published: October 2008

A previously presented model for one-dimensional soil movement by repeated tillage is extended for use under the more complex conditions of long-term field experiments, for (i) following the two-dimensional movement (along and across the plots) of accumulating substances (nutrients, disease organisms, etc.) caused by tillage; (ii) determining the smallest acceptable plot size from given conditions, when planning new long-term field experiments and (iii) determining the size of the discard relative to the size of the treated plot.

Diagrams are given from which rough estimations can be made of both the movement of accumulating substances in long-term field experiments and the smallest acceptable plot size, when a computer with the necessary facilities is not available.
Evaluation and Presentation of Intercropping Advantages
Authors: Willey R. W.
Published: October 2008

It is proposed that two distinct objectives should be recognized in the evaluation of intercropping advantages: (i) a biological objective to determine the increased biological efficiency of intercropping and (ii) a practical objective to determine the advantages that are likely to be obtained by a farmer. The sole crop systems with which intercropping must be compared to satisfy these objectives are defined. Evaluation in relative, absolute, monetary and nutritional units is discussed and some aspects of presenting intercropping data in graphical form are illustrated.
Effects of Intercropping, Mulching and Staking on Growth and Yield of Tomatoes
Authors: Olasantan F. O.
Published: October 2008

The effects of intercropping, mulching and staking on growth and yield of three tomato varieties were evaluated in four field trials in 1982 and 1983. Fruit yields of the improved varieties were significantly reduced by intercropping with okra but the yield of a local variety was unaffected. Though the yield of okra when grown with tomato varieties was less than that of a sole crop, the combined yield of the two crops in mixtures was more than the means of the species in monoculture. Relative Yield Totals (RYT) increased to maxima of about 1.42 and 1.39 when the local variety was grown with okra in 1982 and 1983 trials, respectively. Mulching and staking significantly increased vegetative growth, yield and yield components of the tomato plants. Mulched plants grew taller and had more branches and a greater number and weight of fruits than staked plants. Improved varieties responded better to mulching and staking than the local variety. Growing improved varieties of tomato in sole stands with proper mulching and staking is therefore recommended.
Grain Yield Potential of Some Diverse Maize (Zea mays L.) Morphotypes Intercropped with Cocoyam (Xanthosoma sagittifolium)
Authors: Ayuk-Takem J. A. , Chhedda H. R.
Published: October 2008

Three maize cultivars, BACOA, SAW and COCA, were evaluated when intercropped with cocoyams at a density of 50 000 maize plants and 10 000 cocoyam stands ha−1. BACOA which matures in 120 days, and SAW (130 days) transmitted significantly more light to the lower canopy than COCA, which has spreading leaves and matures in 150 days. Relative yields for BACOA, SAW and COCA in pure stands were 72, 100 and 85%, respectively, while those for cocoyams in BACOA/cocoyam, SAW/cocoyam and COCA/cocoyam mixtures were 82, 58 and 54%, respectively, showing that COCA significantly suppressed the yield of cocoyam when intercropped.

Yields of a COCA type with erect leaves increased as plant density increased from 20 000 to 50 000 plants ha−1 in pure stands, while yields of COCA with spreading leaves increased as plant density increased from 20 000 to 40 000 plants ha−1 but decreased when plant population increased to 50 000 plants ha−1. When COCA with erect leaves was intercropped with cocoyams, cocoyam tuber yields were fairly stable and maize yields continued to increase significantly as plant density increased from 20 000 to 50 000 plants ha−1, whereas the yields of COCA with spreading leaves and cocoyams were greatly reduced when intercropped and when the plant population increased from 20 000 to 50 000 plants ha−1.
Effect of Shoot Removal on Shoot and Root Yields of Sweet Potato
Authors: Dahniya M. T. , Hahn S. K. , Oputa C. O.
Published: October 2008

Experiments on harvesting sweet potato as a green vegetable and as a root crop are described. Whole shoots yielded 62% more than shoot tips. Similar total shoot yields were harvested whether tip removal was at two, three or four week intervals. Root yield was decreased by 31 to 48% by removing shoot tips, while removing whole shoots led to root yield decreases of 48 to 62%. Harvesting shoots at two week intervals gave 72% reduction in root yield, compared with 50% with four week intervals. There were fewer and smaller tubers as the frequency of shoot harvests increased. There were varietal differences in response to shoot removal For reasonable yields of both shoot tips and tuberous roots harvesting shoot tips at four week intervals is recommended.