Extreme climate events have profound impacts on economies and livelihoods of many regions of the world. In Kenya, the extreme climate events often have strong impacts on agriculture production systems in the Arid and ...Extreme climate events have profound impacts on economies and livelihoods of many regions of the world. In Kenya, the extreme climate events often have strong impacts on agriculture production systems in the Arid and Semi-Arid Lands (ASALs). A small change in the mean climate condition can cause large changes in these production systems. There is a paucity of information on trends in climate and climate extremes in the country. However, a joint World Meteorological Commission for Climatology/World Climate Research Programme (WCPRP) project on climate Variability and Predictability (WMO CCl/CLIVAR) Expert Team (ET) on Climate Change Detection, Monitoring and Indices has defined 27 core climate indices mainly focusing on extreme events which can be derived through the use of RClimDex Software. In this study, therefore, the RClimDex software has been used to derive climate extreme indices for five stations in the ASALs of South-Eastern Kenya based on climate data for the period 1961 to 2009. The objective was to examine trends in these extremes to aid agricultural planning and practice. These indices have shown decreasing trends in annual rainfall, rainfall intensity and consecutive wet days but increasing trends in consecutive dry days. Steady warming patterns were evident in both the maximum and minimum temperature indices. This paper concludes that indeed significant changes in climate extremes are apparent in the ASALs of the country and recommends a re-thinking of planning and practice of rain-fed agriculture in the ASALs of South-Eastern Kenya.展开更多
Erratic rainfall and temperature regimes, strongly affect agricultural productivity. To address the reduction in production, this study assessed the effect of Zai pit depths on selected soil properties and cowpea grow...Erratic rainfall and temperature regimes, strongly affect agricultural productivity. To address the reduction in production, this study assessed the effect of Zai pit depths on selected soil properties and cowpea growth and grain yield. “Zai” pit technology was tested in two locations falling under Agroecological Zone IV (relatively dry areas) <i>i.e.</i> Katumani in Machakos County and Naivasha in Nakuru County, Kenya, aiming to determine the combined effect of four “Zai” pit depths and two levels of manure (plots with manure and plots without manure) on selected soil properties, growth and yield of cowpea. Experiment was laid out in split plot arrangement, with manure levels as the main plot factor and “Zai” pit depths (Flat: Z<sub>0</sub>, 30 cm: Z<sub>30</sub>, 45 cm: Z<sub>45</sub> and 60 cm: Z<sub>60</sub>) as subplot factor, replicated four times. Cowpea (M66 variety) was used as the test crop. Inorganic N and extractable P were significantly (P < 0.05) higher, at 1.37 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for N<sub>in</sub> and 80.4 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for P<sub>ex</sub> in Zai pits compared to flat plots which were at 0.91 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for N<sub>in</sub> and 47.1 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for P<sub>ex</sub>. The values of N<sub>in</sub> and P<sub>ex</sub> also varied depending on depths, with Z<sub>45</sub> having highest N<sub>in</sub> at 1.17 against the least, at 0.89 in the Z<sub>0</sub>, while Pex was highest in Z<sub>30</sub> at 102.3 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> while Z<sub>0</sub> having the least P<sub>ex</sub> of 89.7 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup>. Generally, crops in “Zai” pitted plots were larger in diameter at 0.46 cm than crops in flat plots at 0.42 cm. Better performance was observed in yield, with Z<sub>30</sub> yielding 30.5% against 18.2% Flat plots in Machakos while 27.9% in Z<sub>30</sub> against 22.5% from Flat plots in Naivasha. This study demonstrated great potential of “Zai” pit technology on crop production, as reflected on improved growth and yield of cowpeas. Combining “Zai” pits with manure increases soil N<sub>in</sub>, P<sub>ex</sub> and is a guarantee of great crop performance in terms of high final yields.展开更多
This paper examines the changing climatic scenarios and the associated effects on livestock farming in the arid lands(ASALs)of Kenya which covers over 80%of the country.This study was carried out in the semi-arid Muko...This paper examines the changing climatic scenarios and the associated effects on livestock farming in the arid lands(ASALs)of Kenya which covers over 80%of the country.This study was carried out in the semi-arid Mukogodo Division of Laikipia District.This division received a mean annual rainfall of about 507.8 mm and the main source of livelihood was livestock farming.Questionnaire, structured interview,observation and literature展开更多
Brown planthopper, the sap sucking hemipteran pest, is one of the major contributors to the yield loss of rice through the world. To combat the situation researchers are interested identifying genes from plant origin ...Brown planthopper, the sap sucking hemipteran pest, is one of the major contributors to the yield loss of rice through the world. To combat the situation researchers are interested identifying genes from plant origin having potentiality to develop hemipteran pest resistance. Interestingly, it was observed that rice plants expressing ASAL, a monocot mannose binding lectin, showed significant resistance to brown planthopper and green leafhopper. Additionally, antibiotic resistant marker gene free ASAL expressing rice lines were developed to overcome the biosafety issues. However, the basis behind the resistance against planthoppers is still not clearly understood. Ligand blot assay was performed with total BBMV protein from BPH and a ~56 kDa receptor protein was detected. LC MS/MS analysis revealed that the receptor protein is NADH quinone oxidoreductase (NQO), a key player in electron transport chain, insect defense response and male/female gametogenesis. Presumably interaction of ASAL with NQO may lead to toxicity and loss of fecundity among BPH feeding on ASAL expressing transgenic rice plants. These findings provide a stable scientific basis for considering these transgenic ASAL expressing rice plants as significant product for combating BPH attack associated yield loss of rice.展开更多
文摘Extreme climate events have profound impacts on economies and livelihoods of many regions of the world. In Kenya, the extreme climate events often have strong impacts on agriculture production systems in the Arid and Semi-Arid Lands (ASALs). A small change in the mean climate condition can cause large changes in these production systems. There is a paucity of information on trends in climate and climate extremes in the country. However, a joint World Meteorological Commission for Climatology/World Climate Research Programme (WCPRP) project on climate Variability and Predictability (WMO CCl/CLIVAR) Expert Team (ET) on Climate Change Detection, Monitoring and Indices has defined 27 core climate indices mainly focusing on extreme events which can be derived through the use of RClimDex Software. In this study, therefore, the RClimDex software has been used to derive climate extreme indices for five stations in the ASALs of South-Eastern Kenya based on climate data for the period 1961 to 2009. The objective was to examine trends in these extremes to aid agricultural planning and practice. These indices have shown decreasing trends in annual rainfall, rainfall intensity and consecutive wet days but increasing trends in consecutive dry days. Steady warming patterns were evident in both the maximum and minimum temperature indices. This paper concludes that indeed significant changes in climate extremes are apparent in the ASALs of the country and recommends a re-thinking of planning and practice of rain-fed agriculture in the ASALs of South-Eastern Kenya.
文摘Erratic rainfall and temperature regimes, strongly affect agricultural productivity. To address the reduction in production, this study assessed the effect of Zai pit depths on selected soil properties and cowpea growth and grain yield. “Zai” pit technology was tested in two locations falling under Agroecological Zone IV (relatively dry areas) <i>i.e.</i> Katumani in Machakos County and Naivasha in Nakuru County, Kenya, aiming to determine the combined effect of four “Zai” pit depths and two levels of manure (plots with manure and plots without manure) on selected soil properties, growth and yield of cowpea. Experiment was laid out in split plot arrangement, with manure levels as the main plot factor and “Zai” pit depths (Flat: Z<sub>0</sub>, 30 cm: Z<sub>30</sub>, 45 cm: Z<sub>45</sub> and 60 cm: Z<sub>60</sub>) as subplot factor, replicated four times. Cowpea (M66 variety) was used as the test crop. Inorganic N and extractable P were significantly (P < 0.05) higher, at 1.37 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for N<sub>in</sub> and 80.4 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for P<sub>ex</sub> in Zai pits compared to flat plots which were at 0.91 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for N<sub>in</sub> and 47.1 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for P<sub>ex</sub>. The values of N<sub>in</sub> and P<sub>ex</sub> also varied depending on depths, with Z<sub>45</sub> having highest N<sub>in</sub> at 1.17 against the least, at 0.89 in the Z<sub>0</sub>, while Pex was highest in Z<sub>30</sub> at 102.3 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> while Z<sub>0</sub> having the least P<sub>ex</sub> of 89.7 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup>. Generally, crops in “Zai” pitted plots were larger in diameter at 0.46 cm than crops in flat plots at 0.42 cm. Better performance was observed in yield, with Z<sub>30</sub> yielding 30.5% against 18.2% Flat plots in Machakos while 27.9% in Z<sub>30</sub> against 22.5% from Flat plots in Naivasha. This study demonstrated great potential of “Zai” pit technology on crop production, as reflected on improved growth and yield of cowpeas. Combining “Zai” pits with manure increases soil N<sub>in</sub>, P<sub>ex</sub> and is a guarantee of great crop performance in terms of high final yields.
文摘This paper examines the changing climatic scenarios and the associated effects on livestock farming in the arid lands(ASALs)of Kenya which covers over 80%of the country.This study was carried out in the semi-arid Mukogodo Division of Laikipia District.This division received a mean annual rainfall of about 507.8 mm and the main source of livelihood was livestock farming.Questionnaire, structured interview,observation and literature
文摘Brown planthopper, the sap sucking hemipteran pest, is one of the major contributors to the yield loss of rice through the world. To combat the situation researchers are interested identifying genes from plant origin having potentiality to develop hemipteran pest resistance. Interestingly, it was observed that rice plants expressing ASAL, a monocot mannose binding lectin, showed significant resistance to brown planthopper and green leafhopper. Additionally, antibiotic resistant marker gene free ASAL expressing rice lines were developed to overcome the biosafety issues. However, the basis behind the resistance against planthoppers is still not clearly understood. Ligand blot assay was performed with total BBMV protein from BPH and a ~56 kDa receptor protein was detected. LC MS/MS analysis revealed that the receptor protein is NADH quinone oxidoreductase (NQO), a key player in electron transport chain, insect defense response and male/female gametogenesis. Presumably interaction of ASAL with NQO may lead to toxicity and loss of fecundity among BPH feeding on ASAL expressing transgenic rice plants. These findings provide a stable scientific basis for considering these transgenic ASAL expressing rice plants as significant product for combating BPH attack associated yield loss of rice.
