Fertilizer application enhances establishment of cacao seedlings in plant-parasitic nematodes infected soil | Uporaba gnojil pospešuje rast sadik kakavovca v tleh okuženih s parazitskimi ogorčicami

Inglés. Low soil fertility, pests and diseases are major problems of growth and establishment of cacao seedlings on the field. Cocoa production increases by new plantings and rehabilitation of moribund farms, but a build-up of plant-parasitic nematodes (PPN) causing dieback and declining soil fertility has discouraged many farmers, leading to a reduction in crop productivity.  In this study, the potentials of some organic wastes as fertilizers and their effects on establishment of cacao seedlings in PPN infected soils was investigated at Ibadan and Owena of Southwestern Nigeria. Goat dung (GD), organic fertilizer (OF), organo-mineral fertilizers (OMF) and NPK 15:15:15 were applied at 200, 400 and 600 kg ha-1, respectively, to cacao seedlings one month after transplanting, while unfertilized served as control. Results from the experiments showed a significant increase in percentage survival of cacao seedlings under organic fertilizers at Ibadan and Owena compared to NPK and control even at the lowest rate of 200 kg ha-1 3 years after transplanting. The incorporation of GD, OF and OMF significantly reduced the population densities of PPN compared to control. Therefore, GD, OF and OMF at 200 kg ha-1 are recommended for soil application to enhance the field establishment of cacao seedlings in the soil infected with PPN.

Esloveno. Slaba rodovitnost tal, škodljivci in bolezni so glavni problem pri vzgoji sadik kakavovca na prostem. Pridelava kakava se povečuje z novimi nasadi in obnovo zanemarjenih kmetijskih zemljišč, a pojav parazitskih ogorčič (PPN), ki povzročajo propad sadik in zmanjšana rodovitnost tal jemljeta pri tem mnogim kmetom pogum, kar vodi v zmanjšanje v pridelavi te kulture. V tej raziskavi je bil preučevan potencial nekaterih organskih ostankov kot gnojil in njihov vpliv na rast sadik kakavovca v z ogorčicami (PPN) okuženih tleh v Ibadanu in Oweni, v jugovzhodni Nigeriji. Uporabljeni so bili kozji gnoj (GD), organska gnojila (OF), organsko-mineralna gnojila (OMF) in NPK 15 : 15 : 15 v odmerkih 200, 400 in 600 kg ha-1, v nasadu kakavovca en mesec po presaditvi in kot kontrola nepognojen nasad. Rezultati poskusa so pokazali značilno povečanje preživetja sadik kakavovca pri gnojenju z organskimi gnojili v Ibadanu in Oweni v primerjavi z gnojenjem s NPK in kontrolo, celo pri najmanjšem gnojenju z organskimi gnojili, 200 kg ha-1 , 3 leta po presaditvi. Vnašanje GD, OF in OMF v tla je značilno zmanjšalo gostoto populacij ogorčic v primerjavi s kontrolo. Zaradi tega priporočamo gnojenje z GD, OF in OMF v odmerku 200 kg ha-1 za uspešno rast sadik kakavovca v tleh okuženih s parazitskimi ogorčicami.