Differences between tree species in hydraulic press calibration of leaf water potential are correlated with specific leaf area

. To determine the usefulness of the J-14 Hydraulic Press (Campbell Scientific, Inc., Logan, Utah, U.S.A.) in estimating leaf water potential, we calibrated the J-14 Press against a Scholander-type pressure chamber for leaves of various tree species. The species tested were: Acer saccharum, Acer negundo, Acer rubrum. Populus tremuloides, Populus grandidentata, Quercus rubra , and Brassaia actinophylla (Schefflera). The regression calibrations were linear with standard errors about the regression less than 0.1 MPa. The regression equations for the four genera were significantly different, with the y- intercept increasing and the slope decreasing in order of decreasing specific leaf area (SLA). There were no significant differences between species of the calibration lines within the genera Acer and Populus. These data may indicate that leaves with lower SLA resist mechanical compression by the hydraulic press, causing the J-14 Press to be less sensitive to differences of leaf water potential. Therefore the J-14 Press is only a relative measure of leaf water status and does not measure leaf water potential.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73416/1/1365-3040.ep11591871.pd

Socio-economics of land development for sustainable agricultural production in some villages in Mikese division, Morogoro district, Tanzania.

The purpose of this study was to examine the socio-economics of resource use in the traditional farming system in selected villages in Mikese Division, Morogoro Rural District. Data collection was based on surveys using a structured questionnaire. Tools of analysis employed included descriptive statistics, gross margins, mUltiple regression and correlation analysis. The results reveal that most of the farmers in the survey area have one plot around the homestead and additional plots located away from the households. Households with one plot vary from 35% in Mkambarani to 45% in Fulwe. Forty to thirty five percent in Rubungo and Maseyu respectively have one plot. In basically all villages, households with 2 to 3 plots ranges between 30 and 45 percent. About 25% of the households in the villages have 4 to 5 plots. Households with more than 5 plots range from 4% in Rubungo to 10% in Maseyu. Thirty five to forty five percent of the households in the four villages have their plots located 1.0 km away from the homesteads. A greater percentage of households from Fulwe and Maseyu however, have their plots located some 2.0 km away from the homesteads. Only 20% of Rubungo and 15% of Mkambarani have their plots located 2.0 km away from the homesteads. Plots located 3-5 km away from the homesteads vary from 10-15% in Rubungo, Fulwe and Maseyu and 10-25% in Mkambarani. The average cultivated area per family ranged from 10.5 to 23.5 hectares for all crops. The main crops grown in the four villages are maize, paddy, cotton, sesame, sunflower, cowpeas and cassava. The results indicate that maize was grown in all villages and form the biggest crop farm size. Maize yields per hectare varied from 800 kilogrammes per hectare in Rubungo to 1000 kilogrammes per hectare in Mkambarani. Paddy, which forms the second biggest crop farm size is mainly grown in Mkambarani (3.5 ha per household). The other villages grow about 1.0 ha per household. Cotton which forms the third biggest farm size in the villages studied yields 2,500 kilogrammes per hectare in Maseyu and 3,500 kilogrammes per hectare in Mkambarani. Mkambarani has also the biggest hectarage of sunflower with 3.9 ha per household, followed by Rubungo, Maseyu and Fulwe with 1.4, 1.3, and 1.2 hectares per household respectively. Mkambarani appears also to lead in cassava production, 1.8 ha per household followed by Rubungo and Maseyu with 1.2 ha per household each. Fulwe has an average of 0.8 ha per household

Socio-economics of land development for sustainable agricultural production in some villages in Mikese division, Morogoro district, Tanzania.

The purpose of this study was to examine the socio-economics of resource use in the traditional farming system in selected villages in Mikese Division, Morogoro Rural District. Data collection was based on surveys using a structured questionnaire. Tools of analysis employed included descriptive statistics, gross margins, mUltiple regression and correlation analysis. The results reveal that most of the farmers in the survey area have one plot around the homestead and additional plots located away from the households. Households with one plot vary from 35% in Mkambarani to 45% in Fulwe. Forty to thirty five percent in Rubungo and Maseyu respectively have one plot. In basically all villages, households with 2 to 3 plots ranges between 30 and 45 percent. About 25% of the households in the villages have 4 to 5 plots. Households with more than 5 plots range from 4% in Rubungo to 10% in Maseyu. Thirty five to forty five percent of the households in the four villages have their plots located 1.0 km away from the homesteads. A greater percentage of households from Fulwe and Maseyu however, have their plots located some 2.0 km away from the homesteads. Only 20% of Rubungo and 15% of Mkambarani have their plots located 2.0 km away from the homesteads. Plots located 3-5 km away from the homesteads vary from 10-15% in Rubungo, Fulwe and Maseyu and 10-25% in Mkambarani. The average cultivated area per family ranged from 10.5 to 23.5 hectares for all crops. The main crops grown in the four villages are maize, paddy, cotton, sesame, sunflower, cowpeas and cassava. The results indicate that maize was grown in all villages and form the biggest crop farm size. Maize yields per hectare varied from 800 kilogrammes per hectare in Rubungo to 1000 kilogrammes per hectare in Mkambarani. Paddy, which forms the second biggest crop farm size is mainly grown in Mkambarani (3.5 ha per household). The other villages grow about 1.0 ha per household. Cotton which forms the third biggest farm size in the villages studied yields 2,500 kilogrammes per hectare in Maseyu and 3,500 kilogrammes per hectare in Mkambarani. Mkambarani has also the biggest hectarage of sunflower with 3.9 ha per household, followed by Rubungo, Maseyu and Fulwe with 1.4, 1.3, and 1.2 hectares per household respectively. Mkambarani appears also to lead in cassava production, 1.8 ha per household followed by Rubungo and Maseyu with 1.2 ha per household each. Fulwe has an average of 0.8 ha per household