Monitoring and blunting coping styles as assessed by the Miller Behavioral Style Scale were related to desire for more information, factual knowledge and vigilant health behaviour in women admitted for gynaecological surgery.
Root crops are an important staple food in the Pacific region. Yields are generally low and inorganic fertilizers are deemed an option to increase root crop production. The effects of inorganic N fertilizers on upland taro (Colocasia esculenta (L.) Schott) and sweet potato (Ipomoea batatas (L.) Lam.) were quantified with the aim to investigate relationships between inherent soil fertility, N uptake, N application rates and crop yield. The research took place on a sandy, Typic Tropofluvents in the humid lowlands of Papua New Guinea. Five levels of fertilizer N (0,100, 200, 300 and 400 kg ha −1 ) were given in split applications. The yield of marketable taro corms was not affected by N fertilizer but non-marketable corm yield doubled at high N fertilizer rates. High N applications yielded 8-11 Mg ha −1 more taro tops. Marketable and non-marketable sweet potato yield was negatively affected by N fertilizers. High N applications yielded 26 Mg ha −1 more vines than the control treatment. Nitrogen fertilizer significantly reduced the harvest index in both crops. When no fertilizer was applied, the total N uptake of taro was 32.0 kg ha −1 of which 9.7 kg was taken up in the marketable corms. At 400 kg N ha −1 the total N uptake was 67.5 kg ha −1 of which 23% was taken up by the marketable corms. Uptake of N in the marketable sweet potato tubers was less than 11 kg ha −1 and for most treatments more N was taken up in the non-marketable tubers than in the marketable yield. Up to 156 kg N ha −1 was taken up with the sweet potato vines. Despite the negative effect of N on sweet potato yield, sweet potato had a higher N use efficiency than taro due to a higher above-ground biomass production. The N fertilizer recovery was 25% for the sweet potato but only 9% for the taro indicating considerable N losses, likely caused by leaching.
Sweet potato (Ipomoea batatas (L.) Lam) is the major staple crop in Papua New Guinea and experiments were conducted investigating factors affecting yield decline. Yields of unfertilized plots were related to rainfall and measured changes in soil properties, nematode (Meloidogyne sp., Rotylenchulus reniformis) and sweet potato weevil (Cylas formicarius) populations. The research took place at two locations (Hobu and Unitech) on Eutropepts and Fluvents, respectively. Yields at Hobu decreased from 18 Mg ha −1 in the first season to around 7 Mg ha −1 in the third season, but no significant yield trend was observed at Unitech. Vine biomass was not affected by the number of cropping seasons at Hobu but it decreased at Unitech with time. Marketable tuber yield at both sites was significantly correlated to rainfall, i.e. the more rain the lower the yield. Significant changes in soil chemical properties included a decrease in pH and base saturation (Hobu) and a decrease in CEC and exchangeable K (Unitech). No significant changes in soil bulk density were found and no obvious pattern was found in the nutrient concentrations of leaf samples with time. Nematode populations were high and tripled between the first and third season at Hobu. Half of the vines at Hobu and all of the vines at Unitech were damaged by sweet potato weevils, but tuber damage was higher in Hobu although the damage was only superficial. Despite the considerable variation in yield and yield determining factors, the study showed that the decline in sweet potato yield may be attributed to the high nematode infestation, accompanied by an increase in vine damage by weevils and a declining soil fertility.
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