Fertilizer use on the different crops across agro ecological zones is presented in Annex 2. Both adoption and application rates are higher in the zones with higher agro ecological potential than in lower agro ecologically potential zones. This may indicate that fertilizer use on the crops is more profitable and less risky in higher agro ecologically potential zones.The marginal effects of the Probit model show changes in the probability of adoption of fertilizer for additional unit increase in the independent variables. Farmers with no formal education had 7.6% less probability of adopting fertilizer compared to those with primary education, while farmers with secondary and post-secondary education respectively had 11.2% and 16.5% higher probability of adopting fertilizer than their counterparts with primary education. Educated farmers can better process information more rapidly than otherwise . It can also be presumed that educated farmers have a higher level of awareness of the benefits of fertilizer use in agricultural production.Having received credit increased probability of fertilizer adoption by 12.9%. This suggests that relaxing liquidity binding constraints among smallholder farmers through access to credit will significantly increase their probability of adopting fertilizer. Growing a cash crop is associated with 15.3% higher probability of fertilizer adoption. The major cash crops considered here have credit schemes that guarantee farmers’ input acquisition on credit,round pot which is repaid through deductions from the produce which farmers sell through the commodity cooperatives or factories. This indicates the important role of credit and guaranteed markets in promoting fertilizer adoption.
The probability of adopting fertilizer decreases by 0.7% for every kilometre increase in the distance to fertilizer seller. It is noteworthy that the distance to the nearest fertilizer seller declined from 8.1 km in 1997 to 3.4 km in 2007, which could be a result of improved input delivery systems after liberalization . Agro ecological potential significantly influences fertilizer adoption. Households in the drier and lower agro ecologically potential zones had between 50.8% and 77.2% lower probability of adopting fertilizer compared to those in the High potential maize zones, an indication that profitability of fertilizer use as dictated by ago ecological conditions has a significant impact on adoption. Compared to the Central highlands, an equally high potential region, probability of fertilizer adoption in the High potential maize zone was lower by 6.6%.Determinants of fertilizer use intensity conditional on adoption are presented in Table 6. Having no education at all or secondary education compared to having primary education no longer plays significant role in fertilizer use intensity. The significant determinants of fertilizer use intensity are gender, post-secondary education, household size, dependency ratio, credit, growing of cash crop, distance to fertilizer seller, distance to extension and agro ecological potential. The marginal effects show that for an additional year of age, fertilizer use intensity declines by 0.12kg/acre. A household being male-headed is associated with 6.6 kg of additional fertilizer per acre. Compared to primary education, post-secondary education increases fertilizer application rate by 4.5kg/acre. A unit increase in the household size increases fertilizer application rate by 0.49kg/acre. This is plausible as households will strive to enhance their food security status by trying to increase yield levels. At the means, a unit increase in dependency is associated with a reduction of fertilizer use intensity by 2.5kg/acre.Conditional on a household using fertilizer, receiving credit increases fertilizer application rate by 16.2kg/acre, while growing a cash crop increases fertilizer application rate by 19kg/acre.
A one kilometre increase in the distance to an extension service reduces fertilizer application rate by 0.8kg/acre. Paradoxically, unlike in the Probit model where distance to fertilizer seller negatively and significantly influenced fertilizer adoption, an increase in the distance to fertilizer seller positively and significantly influences fertilizer use intensity. This is a puzzling issue that may need further investigation.Fertilizer is considered one of the most important inputs for the achievement of increased agricultural productivity and food security in Kenya and, in deed, SSA. Although Kenya has registered high rates of fertilizer adoption, raising the intensity of use remains a key challenge. The patterns in households’ fertilizer use showed dramatic rise in adoption in the last decade. Fertilizer application rates, however, showed marginal increase over the period. Fertilizer use in the drier agro ecological zones is still way below that in the higher agro ecologically potential zones. This may be associated with higher risk involved in and lower profitability of using fertilizer in the drier areas. The relatively higher fertilizer use in higher agro ecologically potential zones may also be influenced by the presence of major cash crops such as tea, sugarcane and coffee, which have organized input credit schemes which allow farmers to acquire inputs on credit and repay through deductions made on deliveries of the produce. Econometric analysis has shown that age, education, credit, growing cash crop, distance to fertilizer market and agro ecological potential are statistically significant in influencing the probability of adopting fertilizer. On the other hand, the strongest determinants of fertilizer use intensity were gender, household size, dependency ratio, credit, growing cash crop, distance to extension services and agro ecological potential. Increasing fertilizer use intensity in general and promoting fertilizer adoption in drier areas of Kenya require several interventions. First, there is need for relaxation of credit constraint through improved access to agricultural credit for especially low income farmers who depend on food crops and do not have access to credit opportunities offered under cash crops’ input credit schemes. Another way of relaxing credit constraint would be to improve access to viable off-farm income generating activities.
Existing literature suggests positive spill over effects of off-farm income on agriculture by substituting for credit when credit markets fail . Secondly, concerted efforts to promote fertilizer use among farmers in the drier areas cannot be overemphasized. Extension efforts combined with fertilizer distribution innovations would ensure that farmers in these areas are sensitized on the benefits of using fertilizer for productivity growth. In addition, long term efforts are needed to establish and expand small-scale irrigation projects, which can help overcome the adverse effects of inadequate rainfall experienced in these areas. Finally,round plastic planter the liberalization of the fertilizer sub-sector has led to increased national consumption of fertilizer and Kenya has been a success case where the private sector has thrived relatively well. One of the current factors impeding fertilizer use is the high world fertilizer prices in relation to the output price for commodities . The world prices per ton of DAP increased from US$ 260 in 2007 to US$ 800 in 2008. If such trends continue, gains in fertilizer adoption and intensity of use over the last decade may erode. Efforts to reduce the costs of fertilizer delivery would help to offset the effects of rising world prices. Government can invest in rural infrastructure, efficient port facilities and standards of commerce to reduce the costs of distributing fertilizer.Twenty-five years after the publication of the first IPCC Assessment Report, it is instructive to step back and ask what we have learned about the economic impacts of climate change to the agricultural sector, not just from a technical standpoint, but from a conceptual one. California is an ideal focus for such an analysis both because of its strong agricultural sector and proactive climate policy. After passing the 2006 Global Warming Solutions Act, the state has sponsored research to complete three climate change assessments, with the fourth assessment report in progress at the time of submitting this paper. This effort to study adaptation appears to be relatively more prolific than in many other global sub-regions, particularly over the past decade . Assessing adaptation potential — the institutional, technological, and management instruments for adjusting to actual or expected climatic change and its effects — represents an important turning point in the climate impacts literature. The important role of responsive decision-making by farmers and institutions is recognized for the first time as the key ingredient to dampening the effects of climate change . Adaptation was simply mentioned as an optimistic afterthought in earlier studies, which suggested that agriculture would fully or mostly adjust in the long term — although there was sparse detail on how it would do so . When adaptation was directly included in the modeling framework, economists found that the estimated welfare damages from climate change documented in previous studies declined . In colloquial terms, this is a shift from modeling the “dumb” farmer to modeling one with reasonable economic agency. There are four key concepts linked to the idea of adaptation: vulnerability, adaptive capacity, economic welfare, and economic efficiency. In the IPCC literature, adaptation is connected to the foundational concept of vulnerability, defined as the propensity for agricultural systems to be affected by future climatic changes . Vulnerability can also be defined endogenously as the ability of farmers and institutions to respond and adapt to, and recover from such changes .
This latter definition is synonymous with the concept of adaptive capacity, or the ability of a system to moderate potential damages and take advantage of adaptation and mitigation opportunities to reduce vulnerability of the system to climatic changes . Economic welfare is the sum of producer and consumer surplus in the agricultural sector. Adaptation dampens welfare losses caused by climate change. The relationship of adaptation with vulnerability is more complex, and better represented as that of trade-offs. For example, changing the crop mix in favor of high value crops may reduce vulnerability to water scarcity, but it may increase vulnerability to heat tolerance. Finally, the concept of efficient adaptation has been defined as a situation where the costs of effort to reduce climate-induced damages is less than the resulting benefits from adapting . Given the central role of farmer and institutional responsiveness, how do recent agro-economic assessments suggest that specific adaptations may improve economic welfare and reduce vulnerability? What is economically efficient adaptation in the short and long-run? What are the limits to the agricultural sector’s adaptive capacity? This is certainly not the first review of climate impact assessments to California agriculture. Smith and Mendelsohn highlighted the importance of regional climatic impacts to several economic sectors in California , integrating across range of modeling approaches . The agricultural impacts are calculated by the Statewide Agricultural Production model under wet and dry scenarios. The results echo those of more recent SWAP studies, suggesting that field crop usage will decline by the end of the century under a dry scenario, though the decline in revenues will be partially offset by increased production of high-value crops. Prior to Smith and Mendelsohn , several notable studies examined the state of the knowledge of climate assessments at the US level . In particular, Lewandrowski and Schimmelpfennig integrate the knowledge from both programming and econometric studies of the agricultural sector. Other reviews have focused on the technical details of the different modeling approaches without discussing the results of the various studies . Following the pioneering work of Smith and Mendelsohn , this paper also focuses on California. The state is a leader in agricultural production, with $53.5 billion in sector cash receipts in 2014. California accounts for roughly 2/3 of US fruit/nut production, and 1/3 of US vegetable production . Roughly 1/3 of California cropland, or 9 million acres, is irrigated , making the state’s agricultural sector highly vulnerable to changes in groundwater and surface water supply . Several programming and econometric studies have been published after Smith and Mendelsohn , that operationalize the concept of adaptation . This paper begins with a review of regional impacts of climate change to California agriculture. It is followed by a review of the results from recent programming and econometric studies. The final section synthesizes the results from these studies, addressing lessons learned about vulnerability,adaptation, and adaptive capacity; and how these relate to economic welfare and efficiency.Observational studies indicate that average daily temperature and daily minimum temperatures, particularly during the winter season, have increased in California . Average daily temperature in the US Southwest for the previous decade has been higher than any decade observed in the previous century . Barnett et al. find that daily minimum temperatures in winter have increased between 0.28– 0.43 C per decade from 1950–1999. Not just magnitude, but an increased rate of warming has been observed. Karl et al. suggest that the US Southwest has experienced the most rapid rate of warming in the nation. Observed precipitation patterns are fundamentally more complex and variable than temperature, exhibiting a high degree of variability across space and time.