Feeding costs could be reduced by use of alternative energy and protein sources. Leguminous trees remain green through the dry season, serving as a crude protein bank besides improving soil fertility through nitrogen ...Feeding costs could be reduced by use of alternative energy and protein sources. Leguminous trees remain green through the dry season, serving as a crude protein bank besides improving soil fertility through nitrogen fixation, nutrients recycling and stabilising soil on terraces. Some Kenyan farmers intercrop bananas with forages to cope with the perennial feed shortages. A simulation model assumed a family of six （husband, wife and four children） owning one cow producing 15 kg milk per day, living on 0.4 ha of land. Bananas grown on 0.36 ha in alleys of alternating rows ofLeucaena diversifolia and Calliandra calothyrses, intercropped with Guinea grass （Panicum maximum） and Desmodium uncinatum. Napier （Pennisetum purpureum） was planted in the alleys as a pure stand on 0.08 ha. Model analysis showed the household had adequate energy and protein all the year and was financially secured, with income exceeding routine expenditure. There were positive balances for nitrogen and phosphorus, but potassium application was required. A replica of the model was then tested.展开更多
Systematic analyses were conducted including the petrographic features, major and trace elements, Sr and Nd isotopic compositions, and mineral structure and compositions of whole rocks. Mid-Pacific Mountain volcanic r...Systematic analyses were conducted including the petrographic features, major and trace elements, Sr and Nd isotopic compositions, and mineral structure and compositions of whole rocks. Mid-Pacific Mountain volcanic rocks are mainly phonotephrite with a porphyritic texture. Phenocrysts are mainly composed of Ca-rich plagioclase, clinopyroxene and nepheline.These volcanic rocks are significantly rich in large-ion lithophile and light rare earth elements, without obvious Eu anomalies(δEu=0.99–1.03), and with relatively enriched^(87) Sr/^(86) Sr(0.703829–0.704313) and^(143) Nd/^(144) Nd isotopic ratios(0.512857–0.512871), suggesting that they have similar but more enriched features than the OIB magmatic source. These volcanic rocks may originate from relatively deep magma source with the existence of spinel-garnet Iherzolites, and have undergone partial melting at a low degree of 1–3%. In addition, The residual Nb-Ta minerals(such as sphene, rutile, perovskite) may remain in the mantle source, and the magma components have undergone metasomatism by carbonate melt/fluid or alkali-rich fluid, causing high contents of incompatible elements and significant loss of Nb, Ta and Ti in these volcanic rocks. There are many similarities between the phonotephrites in the Mid-Pacific Mountain and the volcanic rocks in the Line Islands based on the tectonic settings and the geochemical characteristics. We thus speculate that Site 313 volcanic rocks in the Mid-Pacific Mountain is most likely to be a continuation of the Line Islands.展开更多
文摘Feeding costs could be reduced by use of alternative energy and protein sources. Leguminous trees remain green through the dry season, serving as a crude protein bank besides improving soil fertility through nitrogen fixation, nutrients recycling and stabilising soil on terraces. Some Kenyan farmers intercrop bananas with forages to cope with the perennial feed shortages. A simulation model assumed a family of six （husband, wife and four children） owning one cow producing 15 kg milk per day, living on 0.4 ha of land. Bananas grown on 0.36 ha in alleys of alternating rows ofLeucaena diversifolia and Calliandra calothyrses, intercropped with Guinea grass （Panicum maximum） and Desmodium uncinatum. Napier （Pennisetum purpureum） was planted in the alleys as a pure stand on 0.08 ha. Model analysis showed the household had adequate energy and protein all the year and was financially secured, with income exceeding routine expenditure. There were positive balances for nitrogen and phosphorus, but potassium application was required. A replica of the model was then tested.
基金supported by National Natural Science Foundation of China(Grant Nos.41476034,41272369,40802038,41320104006&41302102)
文摘Systematic analyses were conducted including the petrographic features, major and trace elements, Sr and Nd isotopic compositions, and mineral structure and compositions of whole rocks. Mid-Pacific Mountain volcanic rocks are mainly phonotephrite with a porphyritic texture. Phenocrysts are mainly composed of Ca-rich plagioclase, clinopyroxene and nepheline.These volcanic rocks are significantly rich in large-ion lithophile and light rare earth elements, without obvious Eu anomalies(δEu=0.99–1.03), and with relatively enriched^(87) Sr/^(86) Sr(0.703829–0.704313) and^(143) Nd/^(144) Nd isotopic ratios(0.512857–0.512871), suggesting that they have similar but more enriched features than the OIB magmatic source. These volcanic rocks may originate from relatively deep magma source with the existence of spinel-garnet Iherzolites, and have undergone partial melting at a low degree of 1–3%. In addition, The residual Nb-Ta minerals(such as sphene, rutile, perovskite) may remain in the mantle source, and the magma components have undergone metasomatism by carbonate melt/fluid or alkali-rich fluid, causing high contents of incompatible elements and significant loss of Nb, Ta and Ti in these volcanic rocks. There are many similarities between the phonotephrites in the Mid-Pacific Mountain and the volcanic rocks in the Line Islands based on the tectonic settings and the geochemical characteristics. We thus speculate that Site 313 volcanic rocks in the Mid-Pacific Mountain is most likely to be a continuation of the Line Islands.
