Ridge–furrow mulched with plastic film increases little in carbon dioxide efflux but much significant in biomass in a semiarid rainfed farming system

This research aims to identify factors correlated significantly to the motivation of farmers in perseving traditional rainfed farming systems, such as using local seeds and planting once a year. The population of this study is farmer who still perform the traditional paddy farming system in the Village of North Tapanuli Parbaju Julu County North Sumatra Province. As much as 48 respondents randomly selected from 160 farmers. A descriptive analyse and Spearman rank correlation are applied in this study. The study showed that formal education, farmers' perception of the traditional system of rice farming are correlated significantly to farmer motivation in preserving tradional farming system while non-formal education, the traditional system of farming experience, farm size, number of family members are not. Factors that correlated significantly to farmer motivation in maintaining local seed is non-formal education, farming experience, while the traditional system of formal education, farmers' perception of traditional rice farming system, farm size, number of family members are not correlated significantly. Furthermore, the number of family members is merely factor that correlated significantly to the farmers motivation in maintaining once a year plantings while others factors are not correlated. Key words: farmer motivation, preserving, traditional farming

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Vertical Strata and Stem Carbon Dioxide Efflux in Cycas Trees

Plants ◽

10.3390/plants9020230 ◽

2020 ◽

Vol 9 (2) ◽

pp. 230 ◽

Cited By ~ 2

Author(s):

Thomas E. Marler ◽

Murukesan V. Krishnapillai

Keyword(s):

Carbon Dioxide ◽

Carbon Cycling ◽

Sap Flow ◽

Quadratic Model ◽

Maintenance Respiration ◽

Stem Respiration ◽

Ecosystem Carbon ◽

Vertical Location ◽

Carbon Dioxide Efflux ◽

Cycas Revoluta

Stem respiration is influenced by the vertical location of tree stems, but the influence of vertical location on stem respiration in a representative cycad species has not been determined. We quantified the influence of vertical strata on stem carbon dioxide efflux (Es) for six arborescent Cycas L. species to characterize this component of stem respiration and ecosystem carbon cycling. The influence of strata on Es was remarkably consistent among the species, with a stable baseline flux characterizing the full mid-strata of the pachycaulous stems and an increase in Es at the lowest and highest strata. The mid-strata flux ranged from 1.8 μmol·m−2·s−1 for Cycas micronesica K.D. Hill to 3.5 μmol·m−2·s−1 for Cycas revoluta Thunb. For all species, Es increased about 30% at the lowest stratum and about 80% at the highest stratum. A significant quadratic model adequately described the Es patterns for all six species. The increase of Es at the lowest stratum was consistent with the influence of root-respired carbon dioxide entering the stem via sap flow, then contributing to Es via radial conductance to the stem surface. The substantial increase in Es at the highest stratum is likely a result of the growth and maintenance respiration of the massive cycad primary thickening meristem that constructs the unique pachycaulous cycad stem.

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