نتایج جستجو برای: upland
تعداد نتایج: 5084 فیلتر نتایج به سال:
the bias against mangrove areas in siting fish farms prompted a comparison of the cost structure and yield performance in upland and mangrove locations. tools utilized included descriptive statistics, budgetary and cash flow analyses and profitability ratios. empirical results revealed that substantial revenue could be realized from both farms. while the upland farms yielded average gross reven...
Forested mineral soil wetlands (FMSW) store large stocks of soil organic carbon (SOC), but little is known on: (i) whether the quality of SOC stored in these soils (proportion of active versus more resistant SOC compounds) differs from SOC in upland soils; (ii) how the quality of SOC in FMSW varies with mean annual temperature (MAT); and (iii) whether SOC decomposition rates in these environmen...
Elite crop varieties usually fix alleles that occur at low frequencies within non-elite gene pools. Dissecting these alleles for desirable agronomic traits can be accomplished by comparing the genomes of elite varieties with those from non-elite populations. Here we deep-sequence six elite rice varieties and use two large control panels to identify elite variety tag single-nucleotide polymorphi...
This paper looks at differences in spatial and temporal variation of rice yields in China and Brazil. We find that rice yields in China have converged over time and that rice production has become more and more homogeneous. In contrast, rice yields in Brazil have diverged over time, primarily due to variations in upland rice yields. Three hypotheses are put forward to explain the different beha...
How do farmers in poor, remote upper-watershed areas of developing countries respond to price signals? Until relatively recently, it was widely assumed that most upland agriculture was primarily for subsistence. If correct, this has important implications for the design of upland development programs, as subsistence farmers, by definition, are beyond the reach of economic policies, and programs...
In the world market upland rice (grain) occupies a very modest place, since its production is comparatively limited, and harvests are uncertain since they depend upon precipitation. For this reason upland rice cannot compete with lowland rice. Upland rice is used exclusively in those regions possessing insufficient water for irrigation purposes. CAMUS (2) identifies four types of rice. Of these...
Upland rice (Oryza sativa L.) is mainly grown in Asia, Africa and Latin America. Yield potential of upland rice is quite low and invariably this crop is subjected to many environmental stresses. Further, when upland rice is grown in monoculture for more than two to three years on the same land, allelopathy or autotoxicity is frequently reported. Allelopathy involves complex plant and plant chem...
This paper looks at differences in spatial and temporal variation of rice yields in China and Brazil. We find that rice yields in China have converged over time and that rice production has become more and more homogeneous. In contrast, rice yields in Brazil have diverged over time, primarily due to variations in upland rice yields. Three hypotheses are put forward to explain the different beha...
Landscape heterogeneity causes spatial variation in disturbance regimes and resilience. We asked whether the resilience of bryophyte (liverwort and moss) assemblages to clear-cutting differs between streamside and upland boreal forests in northern Sweden. We hypothesized that bryophyte survival and recolonization rates are higher in streamside areas, thus raising resilience. Conversely, disturb...
The Canadian boreal forest consists of a mosaic of landscapes of varying soil drainage and forest age driven by wildfire. The hydrological consequences are complicated by plant responses to soil moisture and forest age, both potentially influencing evapotranspiration. Evapotranspiration was measured using the energy balance residual technique in 2006 and 2007 at forested upland and fen sites th...
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