Competition of the active roots of Cassia siamea Lam. and Zea mays L.(cv.Katumani Composite B) in an alley cropping trial in semi arid Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＯｎｅｏｆｔｈｅｍａｊｏｒｄｒａｗｂａｃｋｓｏｆａｌｌｅｙｃｒｏｐｐｉｎｇｓｙｓｔｅｍｓｉｎｓｅｍｉａｒｉｄｌｏｗｆｅｒｔｉｌｉｔｙｃｏｎｄｉｔｉｏｎｓｉｓｃｏｍｐｅｔｉｔｉｏｎｆｏｒａｖａｉｌａｂｌｅｗａｔｅｒａｎｄｎｕｔｒｉｅｎｔｓ．Ｃｏｍｐｅｔｉｔｉｏｎｉｓｔｏｂｅｅｘｐｅｃｔｅｄｉｆｔｈｅｔｒｅｅａｎｄｔｈｅｃｒｏｐｈａｖｅｏｖｅｒｌａｐｐｉｎｇａｃｔｉｖｅｒｏｏｔｓｙｓｔｅｍｓｉｎｓｐａｃｅａｎｄｔｉｍｅ．Ａｋｎｏｗｌｅｄｇｅｏｆｔｈｅｓｐａｔｉａｌｄｉｓｔｒ…     

Understanding yields in alley cropping maize (Zea mays L.) and Cassia siamea Lam. under semi-arid conditions in Machakos, eastern Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＯｎｌｙａｂｏｕｔ 2 0 %ｏｆＫｅｎｙａ’ｓｔｏｔａｌｌａｎｄａｒｅａｈａｓｈｉｇｈｐｏｔｅｎｔｉａｌｆｏｒａｇｒｉｃｕｌｔｕｒａｌｐｒｏｄｕｃｔｉｏｎ ,ｔｈｅｒｅｓｔｂｅｉｎｇａｒｉｄｏｒｓｅｍｉ ａｒｉｄ .ＴｈｅａｎｎｕａｌｐｏｐｕｌａｔｉｏｎｇｒｏｗｔｈｒａｔｅｉｎＫｅｎｙａｏｆｃｌｏｓｅｔｏ 4 %ｉｓｏｎｅｏｆｔｈｅｈｉｇｈｅｓｔｉｎｔｈｅｗｏｒｌｄ (ｅ .ｇ .ＵｎｉｔｅｄＮａｔｉｏｎｓＤｅｖｅｌｏｐｍｅｎｔＰｒｏｇｒａｍｍｅ ,1990 ) .Ｔｈｉｓｓｉｔｕａｔｉｏｎｈａｓｌ…     

Leaf area development, dry weight accumulation and solar energy conversion efficiencies of Phaseolus vulgaris L. under different soil moisture levels near Nairobi, Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＫｅｎｙａ○ｓｈｉｇｈｐｏｐｕｌａｔｉｏｎｇｒｏｗｔｈｒａｔｅｈａｓｃｒｅａｔｅｄｐｒｅｓｓｕｒｅｏｎｔｈｅｈｉｇｈｐｏｔｅｎｔｉａｌａｒｅａｓ．Ｔｈｉｓｈａｓｒｅｓｕｌｔｅｄｉｎｔｈｅｍｉｇｒａｔｉｏｎｏｆｐｅｏｐｌｅｔｏｕｎｃｕｌｔｉｖａｔｅｄ“ｍａｒｇｉｎａｌ”ｌａｎｄｓｗｈｉｃｈｍａｋｅｕｐａｂｏｕｔ８０％ｏｆｔｈｅｃｏｕｎｔｒｙａｎｄａｒｅｐｒｅｄｏｍｉｎａｎｔｌｙｏｆｌｏｗａｇｒｉｃｕｌｔｕｒａｌｐｒｏｄｕｃｔｉｖｉｔｙ（Ｈｏｒｎｅｔｚ，１９９０）．Ｔｈｅｓｅ…     

Emission study of a diesel engine fueled with higher alcohol-biodiesel blended fuels

This work examines the effect of butanol (higher alcohol) on the emission pattern of neat neem oil biodiesel (NBD100) fueled diesel engine. Single-cylinder, 4-stroke, research diesel engine was employed to conduct the trial. Blends comprising the mixture of biodiesel and higher alcohol were prepared by employing an ultrasonic agitator. Four test fuels such as neat neem oil biodiesel, diesel, and two blends of higher alcohol/neem oil biodiesel: 10% and 20% (by volume). Experimental result showed that increasing alcohol content to biodiesel brought down the various emissions such as Smoke, NO_x, HC, and CO by 6.8%, 10.4%, 8.6%, and 5.9%, respectively, at all loads. It was also concluded from the trail that a 20% higher alcohol/neem oil biodiesel blends show the promising signs in reducing all the emissions associated with biodiesel fuelled diesel engine.     

Agrometeorology from science to extension: Assessment of needs and provision of services

After a historical introduction, recent achievements in agrometeorology and their limitations are highlighted. It is then discussed what determines what we do in agrometeorology. It is argued that the needs in the livelihood of farmers should push the scientific support systems and it is exemplified that this is possible. This analysis has serious consequences for science, training, education and extension in agrometeorology. This applies most strongly for developing countries or tropical studies elsewhere. Farmers’ livelihoods should be connected through agrometeorological services. Farmer or Climate Field Schools are introduced as a new approach to do so. Examples from China are given in which such schools or classes could be used. Finally a pilot project approach for agrometeorological services is discussed in which this could be prepared.     

Phenotypic nutrient up-take differences in an alley cropping system in semi-arid Machakos, Kenya

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｈｅＦｉｆｔｈＦｒａｍｅｗｏｒｋＰｒｏｇｒａｍｍｅｏｆｔｈｅＥｕｒｏｐｅａｎＣｏｍｍｉｓｓｉｏｎ(ＥＣ,1999),ｕｎｄｅｒ“ｔｏｏｌｓｆｏｒｓｕｓｔａｉｎａｂｌｅｄｅｖｅｌｏｐｍｅｎｔ”,ｔｈｅｒｅｗａｓｒｅｃｅｎｔｌｙａｓｐｅｃｉａｌｃａｌｌｆｏｒｐｒｏｐｏｓａｌｓｆｏｒ“Ｔｅｃｈｎｏｌｏｇｉｅｓｆｏｒｓｕｓｔａｉｎａｂｌｅｐｌａｎｔａｎｄａｎｉｍａｌｐｒｏｄｕｃｔｉｏｎ:ｂｕｉｌｄｉｎｇｂｌｏｃｋｓｆｏｒｉｍｐｒｏｖｅｍｅｎｔ(ｆｏｒｓｍａｌｌｓｃａｌｅｏｒｅｎｖｉｒ…     

Determination of cadmium, zinc, copper, chromium and arsenic in crude oil cargoes

One of the sources of trace heavy metal elements in air is emission by the oil industry, either directly through stack emissions from refineries or indirectly from emissions of combustion of hydrocarbons. Emission estimates are based mainly on the trace metal content of the crude oil processed. From a literature study carried out at the beginning of the 1990s it became clear that data on the trace metal content of crudes were scarce and showed a very large scatter. For this reason a measurement programme to assess the occurrence and concentrations of a number of trace metals, i.e. Cadmium (Cd), Zinc (Zn), Copper (Cu), Chromium (Cr), and arsenic (As), in crudes which are regularly processed in the Netherlands, was set up. By drafting strict sampling protocols and by constructing a special sampling device, as many as possible of the additional contamination sources were avoided. The study suggests that sample contamination may explain a significant amount of the scatter and some of the high concentrations reported in the literature for certain metals. The measured variation in the concentrations of Cd, Zn, and Cu is thought to be due to associated water and/or sediment particles from the producing wells or that picked up during transport. The greater consistency in our measurements for Cr and As suggests that these metals are predominantly associated with the hydrocarbon matrix. Based on the results of this work, it can be concluded that emissions of Cd, Zn, Cu, Cr, and As by the oil industry in the Netherlands are most probably significantly lower than hitherto assumed.     

First-trimester prenatal diagnosis in twin pregnancies

Two twin pregnancies at risk for a sex-linked disorder are described. Both pregnancies were dichorionic. Transabdominal sampling was chosen for prenatal diagnosis. Molecular genetic techniques raised suspicion with regard to the accuracy of the samples in one case. Second-trimester amniocentesis confirmed the error. Selective feticide of the affected fetus was performed. When first-trimester prenatal diagnosis is offered in dichorionic twin pregnancies, confirmation through molecular genetic testing can confirm that villi have been obtained from different fetuses. All parties must be aware that additional invasive diagnostic procedures in the second trimester may be required in cases of doubt.