Browsing by Author "Robinson, J.B.D."
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Item Advisory Soil or Plant Analysis and Fertilizer use(1969) Robinson, J.B.D.Item Advisory Soil or Plant Analysis and Fertilizer use 1- Comparison of Soil Analysis Methods(1968) Semb, C.; Robinson, J.B.D.; E.A.A.F.R.O.Item Advisory Soil or Plant Analysis And Fertilizer Use(1969) Robinson, J.B.D.Item Item Anaerobic Incubation of Soil and the Production of Ammonium(1967) Robinson, J.B.D.In 1964 Waring and Bremner proposed a simple and attractive laboratory method for measuring an index to potentially available mineral nitrogen in the soil under anaerobic conditions of incubation; the original method has been compared with the aerobic incubation procedure of Bremner2.Item Camber Bed Cultivation of Ground-Water (Vlei) Soils I-Experimental Crop Yields(1959) Robinson, J.B.D.; Evans, H.R.; Brook, T.R.; Department of Agriculture, KenyaThe system of raised bed cultivation for clay soils with impeded drainage termed Camber Bed cultivation, has now been under trial at the Coffee Research Station, Ruiru, Kenya, for almost five years. In the previous paper (Robinson et al. 1955) the principles of this cultivation system were described in some detail, together with the method for carrying out the cultivation in the field. At the same time experimental yield data from a 21 factorial nitrogen X phosphorus X cattle manure trial which was cropped with maize (Yellow Durum) in the long rains, 1954, and with beans (White Haricot) in the short rains. 1954, were recorded and discussed in detail.Item Camber Bed Cultivation Of Ground-Water (Vlei) Soils(1959) Evans, H.R.; Robinson, J.B.D.; Brook, T.R.The system of raised bed cultivation for clay soils with impeded drainage termed Camber Bed cultivation, has now been under trial at the Coffee Research Station, Ruiru, Kenya, for almost five years. In the previous paper (Robinson et al. 1955) the principles of this cultivation system were described in some detail, together with the method for carrying out the cultivation in the field. At the same time experimental yield data from a 21 factorial nitrogen X phosphorus X cattle manure trial which was cropped with maize (Yellow Durum) in the long rains. 1954, and with beans (White Haricot) in the short rains,1954, were recorded and discussed in detail.Item Camber Bed Cultivation of Ground-Water (VLEI) Soils: II—Modifications of the System.(1959) Brook, T.R.; Robinson, J.B.D.; Department of Agriculture, KenyaSince the publication of a description of the camber-bed system of cultivation of vlei soils (Robinson et al. 1955), a considerable area of vlei land has been treated in this way, and the experience gained brought out points which required further investigation. Observations during the past two years have shown that the run-off from camber beds can be very high, and it is clear that before the system is put into operation the area should be examined to see if the run-off can be safely discharged into protected drainage ways without risk of damage to roads, culverts, cultivated land etc. In order to test these observations, a six-inch Parshall flume and a recording run-off gauge were installed at the Coffee Research Station, Ruiru, on a camber bed 30 feet wide and 566 feet long, with a fall of 1.15 feet. During the period 5th April to 5th May the rainfall was fairly light, with low intensity, and run-off was so small that it was not recorded, the total rainfall being 9.39 inches in 18 days. From 6th to 16th May, however, 14.84 inches of rain fell in 11 days, sometimes with considerable intensity, and the data in Table I were recorded. From 13th to 16th May, there was a constant flow which was just too low to be recorded, but it was estimated at about 1,500 gallons a day. If this flow is taken into account the percentage run-off is increased to 100 per cent over the greater part of this period. Even discounting this unrecorded flow, it will be seen from the table that the run-off can be as high as 90 per cent.Item Coffee Board of Kenya Monthly Bulletin December 1961(1961) Coffee Board of Kenya; Robinson, J.B.D.; Jones, P.A.; Wallis, J.A.N.Results obtained since 1947 are presented, from field trials and laboratory studies carried out in Kenya to investigate responses of coffee to fertilizers, manure, and mulch. It is shown that economic yield increases were obtained from applications of nitrogen fertilizers, grass mulch, and cattle manure in certain circumstances.Item A Cultivation System for Groundwater (VLEI) Soils(1956) Robinson, J.B.D.; Brook, T.R.; de Vink, H.H.J.; Department of Agriculture, KenyaNow that many planters producing coffee (Coffee arabica) in climatic areas subject to periods of drought appreciate the value of mulching in terms of both soil improvement and enhanced crop yield [I] [2] [3], the need for more land to increase mulch grass production has become a problem on many estates. In addition to the development of suitable land outside the coffee. It is a recommended field practice to remove old, debilitated and uneconomic coffee now growing on the poorer phases of the Kikuyu red loam soil type, and replace it with Napier grass (Pennisefum purpureum) which is still!! Considered to be the most satisfactory mulching material. These areas occur on the steeper slopes, have been subject to severe losses of top soil by sheet erosion in the past, and must in many cases have been unsuitable for coffee even when this crop was first planted. While the need to grow this mulch grass as a "crop". i.e. with adequate cultivation, manuring. etc. to obtain high yields. is stressed, mulch production areas of this type are frequently inadequate and the effective utilization of the ground-water or Vlei soils which occur on many coffee estates for mulch production would be of great assistance.Item Effects of Environment and Cultural Conditions on Potassium, Calcium and Magnesium in Coffee Leaves(1969) Robinson, J.B.D.; East African Agriculture and Forestry Research OrganizationPotassium, calcium and magnesium in coffee leaves are presented as total K + Ca + Mg in dry matter and as percentages (proportions) of this sum. Brazilian coffee and leaf samples collected in different parts of Kenya generally fell within the normal ranges of values reported from the Kivu area in the Congo Republic. Data for Kenya coffee leaves are examined for the influence of season, cultural treatments such as organic mulch and fertilizers, and cropping level, on the concentration and balance of these nutrients.Item The Effects of Exotic Softwood Crops on the Chemical Fertility of a Tropical Soil(October, 1967) Robinson, J.B.D.; E.A.A.F.R.O., Kikuyu, KenyaThe three East African countries, Uganda, Tanzania and Kenya, are undertaking extensive programmes of compensatory forest planting. About 30,000 acres per year are being established with uniform crops of fast growing exotic, mainly coniferous, species. To a large extent, this planting requires the clearing of uneven-aged indigenous forest containing many, mainly broad-leaved, species with evenaged crops of a single coniferous species; sometimes mixtures or belts of different species are planted. In the past, fears have been expressed that this extensive conversion of natural forest to uniform plantation will lead to deterioration in climate, water supplies, soil and other conditions.Item Effects of Organic Mulch on Fertility of a Latosolic Coffee Soil in Kenya(1965) Robinson, J.B.D.; Hosegood, P.H.; East African Agriculture and Forestry Research Organisation, Kikuyu, KenyaMeasurements are reported on the influence of mulch on the chemical and physical characteristics of the soil and the chemical composition of the crop together with growth measurement on an indicator crop in the greenhouse and on mature coffee in the field. Mulch reduced soil acidity; increased organic carbon, Kjeldahl nitrogen, exchangeable potassium and available phosphorus and decreased exchangeable calcium and manganese. It increased total pore space, free-draining pore space and rate of rainfall acceptance in the top soil. Effects on the coffee were to increase phosphorus, potassium and in some cases nitrogen in the leaf, but reduce magnesium and calcium levels. Potassium and calcium levels were increased in feeder roots, Whereas in the ripe cherry the phosphorus level was increased but nitrogen, calcium and magnesium levels were reduced. The soil effects were reflected in increased growth of the indicator crop and mulch improved the growth of the coffee tree in a year of seasonal drought.Item First Specialist Meeting on Coffee Research in East Africa(East African Agriculture and Forestry Research Organization, 1966) East African Agriculture and Forestry Research Organization; Robinson, J.B.D.The need for East African scientists working in coffee to meet for discussion and an exchange of ideas has been recognised for several years. Prior to the meeting reported here, which was held in February, 1966, aspects of coffee research in East Africa had been discussed from time to time at meetings of various Standing and Ad Hoc Committees, when the subject was common to this crop. The East African Agriculture and Forestry Research Organization of the East African Common Services Organization, was pleased, therefore, to make arrangements for the first Specialist Meeting on Coffee Research in East Africa, to be held.Item The influence of fertilizers and manure on the pH Reaction of a coffee soil(1956) Robinson, J.B.D.; Coffee Research Station, Department of Agriculture, KenyaDuring the course of soil-nitrogen studies on the Kikuyu red loam soils at the Coffee Research Station, Ruiru, it. has become apparentthat the soil pH reaction is being influencedvery appreciably by treatments applied in the manurial trials on the Station. A shortterm investigation was undertaken to examine, the effects of various manurial treatments on the soil pH reaction, with particular reference to the use of ammonium sulphate fertiliser and to the question of the position of application in relation to the coffee tree.Item The Influence of Fertilizers and Manure On The Ph. Reaction of a Coffee Soil(1956) Robinson, J.B.D.During the course of soil-nitrogen studies on the Kikuyu red loam soils at the Coffee Research Station, Ruiru, it has become apparent that the soil pH reaction is being influenced very appreciably by treatments applied in the manurial trials on the Station. A shortterm investigation was undertaken to examine the effects of various manurial treatments on the soil pH reaction, with particular reference to the use of ammonium sulphate fertiliser and to the question of the position of application in relation to the coffee treeItem Measuring Soil Nitrogen Available to Crops in East Africa(1968) Robinson, J.B.D.; E.A.A.F.R.O., Kikuyu, KenyaIt has been generally concluded that both the organic matter and the total nitrogen values of cultivated soils are related to crop yields in only a very general way [10]. These soil factors when determined as measures of the nitrogen release to growing crops do not generally provide the degree of differentiation necessary for soil test purposes. The literature does contain occasional references to researches which have illustrated the usefulness of these parameters for defining the soil nitrogen sup- ply to crops.Item The Natural Nitrogen Flush in Different Arable Soils and Climates in East Africa(1969) Robinson, J.B.D.; Semb, G.Working in East Africa Birch [1, 2, 3. 4, 5, 6] has shown that drying soil samples prior to re-moistening them markedly increases the mineralization of natural nitrogen during subsequent incubation, He found that for a particular soil the amount of nitrogen mineralized was a direct function of the logarithm of the length of time that the soil was dry before wetting and incubation, and of the temperature of the soil during the dry period,Item Nitrogen Studies in a Coffee Soil(1961) Robinson, J.B.D.This trial was laid down to compare ammonium sulphate and urea (92 lb. nitrogen per acre per annum) applied in a single or in split applications annually during the Long Rains, plus or minus the presence of a complete Napier grass (Pennietum purpureum K. Schum) mulch cover. The comparison was measured essentially in terms of growth and leaf nitrogen levels and the plots consisted of single trees only. A plot size of a single mature tree is generally madequate to define statistical yield differences between treatments precisely. Furthermore, there were no guard row trees between treatments and it is assumed here that there was no interference between treatments because of this. The crop yields were recorded,
