Browsing by Author "Jones, P.A."
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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 Tillage Study in Kenya Coffee(1954) Pereira, H.C.; Jones, P.A.; East African Agriculture and Forestry Research Organization and Coffee Research Station, Ruiru.The results are presented for the first 5 years of a tillage experiment on arabica coffee involving 3 types of implement (forked hand hoe, tractor-mounted disc harrows and tractor-mounted 3-furrow plough), 3 depths of cultivation down to 6 inches, 3 sub-soiling treatments and 3 weed control policies, namely, (a) clean cultivation, (b) weeds slashed during the two rainy seasons each year and cultivated at the onset of dry weather, and (c) unrestricted weed growth during the rains killed by cultivation only at the onset of dry weather. Weed growth seriously reduced coffee yields in each year, the reductions for 5 years being 39 % for unrestricted weed growth and 27% when weeds were slashed. The highest yields were produced consistently by clean weeding with the forked hoe. Averaged over all weed conditions, disc harrowing gave yields significantly lower than either hoeing or ploughing. Neither depths of tillage nor sub-soiling produced significant yield differences. Cattle manure applied to sub-plots to encourage different levels of weed growth did not increase coffee yields. Tillage treatments had no significant effects on the quality of the crop.Item A Tillage Study In kenya Coffee. The Long Term Effects of Tillage Practices Upon Yield and Growth of Coffee(1963) Wallis, J.A.N.; Jones, P.A.A fifteen-year tillage experiment in Arabic. coffee grown on a red volcanic latosol has shown that weed growth during wet seasons consistently lowers the mean annual yield by between one-quarter and one-third; it also reduces the proportion of large beans. These losses can be mitigated by mowing the weeds or adding cattle manure. No relationship has been detected between the trial results and rainfall, but the yield response to weeding was strongly, although irregularly, affected by the stage of recovery from the cyclic removal of the bearing stems of the coffee. Initially, higher yields were obtained from clean weeding with forked hand-hoes than from the use of tractor-mounted ploughs or disks, but during the final five years these differences disappeared. A tractormounted rotary hoe was developed during these studies which is superior to the forked hand-hoe, provided its use is associated with routine grass mulching.
