Timing of biomass removal from stands of switchgrass (Panicum virgatum L.) impacts the nutrient content of harvested material and fertilizer requirements for subsequent growing seasons. is study was conducted to determine the change in N, P, and K content of harvested switchgrass biomass as a function of the harvest date and to determine the economic consequences of an extended harvest window. Data were produced in a randomized complete block study conducted at the Oklahoma Agricultural Experiment Station, Stillwater, with six replications over three harvest seasons from November of 2007 to March of 2010. Treatments on the established stand of cultivar Kanlow consisted of ve harvest dates separated by about 30 d beginning in late November. Regression equations were used to t yield and N, P, and K concentration response to the harvest date. Delaying harvest beyond December resulted in an average 5.4% decline in harvested biomass per month. Delaying harvest beyond November did not result in a signi cant change in the N concentration in the harvested biomass. However, delaying harvest did result in a signi cant decrease in both P and K content in the harvested biomass. Point estimates from the response functions were used to estimate production cost for each of ve harvest dates beginning with 30 November and ending with 30 March. e quantities of P 2 O 5 and K 2 O fertilizer that would be required to replace the P and K removed with the biomass were used in the budgets. Biomass production cost was similar across harvest dates.
Smallholder agriculture remains the heart of Ghana’s food crop production and crucial to meet the zero-hunger target. Unfortunately, rural households continue to see no significant improvement in their livelihoods, as poverty and food insecurity remain high in these areas. This has raised concerns about the economic viability of smallholder agriculture in Ghana. We estimated propensity score matching on a sample of 581 farmers to determine the economic viability of the smallholder farmers and the impact of farm output commercialization and off-farm diversification on their food security and welfare status. Large-scale (>2 ha) maize production led to 8% more yield and 96% more income than small-scale (≤2 ha) production. At observed mean levels, large-scale farmers performed better in most of the livelihood outcomes. The impact of diversification and commercialization on livelihood outcomes was mixed, based on the scale of production. For small-scale farmers, diversification reduced per capita consumption expenditure, while commercialization improved food security, consumption expenditure, and income. For large-scale farmers, diversification improved yield and food security, while commercialization improved fertilizer application rate and income but reduced yield. Although small-scale farmers are not necessarily doomed, the heterogeneity of farmers’ production scale should be considered in the design of rural agricultural policies.
Energy crop production has been proposed for land of poor quality to avoid competition with food production and negative indirect land use consequences. The objective of this study was to determine the land area requirements, biomass transportation distance, and expected profit consequences of restricting switchgrass biomass production, for use as biofuel feedstock, to marginal land relative to unrestricted land use. The USA soils capability classification system was used to differentiate between high quality land and land of marginal quality. Fifty years of historical weather data were used in combination with a biophysical simulation model to estimate switchgrass biomass yield distributions for land of different quality for counties in the case study region. A mathematical programming model was designed and solved to determine the economic consequences.
Switchgrass (Panicum virgatum L.) has been identified as a model perennial grass species to compete with alternative sources for providing biomass to fulfill cellulosic biofuels provisions of the US Energy Independence and Security Act of 2007. The objective of this study is to determine the value of a more productive switchgrass variety relative to that of the best available alternative. Biomass data were produced in an experiment with four commercial switchgrass cultivars (Alamo, Blackwell, Kanlow, and Cave‐in‐Rock) and five experimental lines over 4 yr at Stillwater, OK. One of the experimental lines, Cimarron, was released as a cultivar in 2008 during the experiment. The remaining four experimental lines were NL93‐2, NSL 2001‐1, NL 94‐2001‐1, and NSU 95‐2001. An ANOVA model is used to test for differences in switchgrass yield. Enterprise budgets are used to calculate net returns and stochastic efficiency analysis is used to investigate yield risk. For a farm‐gate biomass price of $50 Mg−1, expected net returns were estimated to be $80 ha−1 yr−1 greater in postestablishment years for Cimarron than for Alamo. Assuming a year for establishment, nine postestablishment production years, a farm‐gate biomass price of $50 Mg−1, a discount rate of 6.5%, and environmental conditions similar to those that prevailed during the field experiment, the net present value of seeding a field in the region to Cimarron rather than Alamo would be $501 ha−1.
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