Farmland Size Research Articles

ISOLATION OF SNAKE RIVER ISLANDS AND MAMMALIAN PREDATION OF WATERFOWL NESTS

In 1990–1992, we studied predation of waterfowl nests by mammalian predators on 30 islands in a 64-km reach of the Snake River in southwestern Idaho, USA, to identify river flows necessary to protect and enhance migratory bird use of Deer Flat National Wildlife Refuge. We monitored 235–314 Canada goose (Branta canadensis) nests each year and 122 duck nests, primarily mallard (Anas platyrhynchos), in 1991. We calculated island isolation as the flow energy (width × average water velocity [m2/sec]) a predator encountered in crossing to an island. Density of goose nests increased as island isolation increased (P < 0.001). In contrast, visits of terrestrial predators to islands, mammalian predation of goose nests, and variance in predation rates decreased as island isolation increased (P < 0.01). Nests were most frequently depredated by raccoons (Procyon lotor), coyotes (Canis latrans), badgers (Taxidea taxus), and mink (Mustela vison). Multiple regression models explained 67% of the variance in nest density and 48% of variance in predation rates (P < 0.01). Variables of secondary importance relative to island isolation were island size and percentage of farmland on the adjacent mainland. Fewer geese nested (P < 0.01) and predation rates were greater (P = 0.06) on large islands, and more geese nested on islands adjacent to farmland (P = 0.04). We also analyzed rates of nest predation relative to river flows for 21 islands from 1953 to 1992. Mammalian predation of goose nests decreased as island isolation increased with greater river flows (P < 0.01). To identify levels of isolation needed to protect use of islands by nesting waterfowl, we estimated rates of change in nest densities and predation rates with island isolation for a range of regression quantiles. We then calculated levels of island isolation at river flows ranging from 110 to 340 m3/sec. Below flows of 250 m3/sec, nest predation rates increased rapidly. Flows ≥340 m3/sec adequately isolated Snake River islands for nesting waterfowl. Predator visitation and nest predation rates were at a low level, and variability in the rates was at a minimum for these flows.

Land-use change in a small catchment of northern Loess Plateau, China

In China, the new land policy “household responsibility system”, implemented since late 1970s and early 1980s, has advanced China’s agriculture and led to some changes in land-use structure. In this study, land-use change due to this land policy in a small catchment of the Loess Plateau, northern Shaanxi province, China, was studied by an interpretation of two aerial photographs (1975 and 1997). The land-use pattern in 1975 and 1997 was studied by various pattern measures: areal percentage, patch number per unit area, mean patch area, landscape diversity, fractal dimension and relative land-use suitability index. The results indicated that after implementation of the new land policy, the area percentage of terrace farmland, slope farmland, sparse woodland and bushland decreased obviously, while the area and the percentage of dense woodland, orchard and sparse wild grassland increased. Mean patch size of terrace farmland, dense woodland, bushland and sparse wild grassland became larger, while mean patch size of slope farmland, sparse woodland and orchard became smaller. Fractal dimension analysis indicated that, compared with 1975, the patch shape of orchard and slope farmland was becoming complex, while the patch shape of dense woodland, sparse woodland, bushland terrace farmland and sparse wild grassland was becoming more regular. Based on land-use suitability evaluation by calculating the R-value, the present land-use structure appears to be suitable.

Farm land size and onchocerciasis status of peasant farmers in south‐western Nigeria

Concern is being raised about the economic impact of the non-blinding strain of onchocerciasis, since half of those affected with onchocerciasis in Africa live in the forest zones where the non-blinding form is prevalent. WHO's TDR programme has embarked on multi-country studies on the social and economic effects of onchocercal skin disease (OSD). Baseline data from one site, the Ibarapa Local Government Area of Oyo State, Nigeria, is presented here. Farmers were screened for signs and symptoms of onchocerciasis including palpable nodules, reactive skin lesions and self-reported severe itching. Those having two or more of these conditions were classified as having severe OSD. A matching group of farmers without any of the signs or symptoms formed a control group. Women in the area either did not farm or held only one small plot. Land size comparisons were undertaken with 51 pairs of male farmers matched for age and location within 23 small hamlets bordering the Ogun River. Farmers with OSD had significantly less farmland under cultivation (9117 m2) than those with no OSD (13850 m2). The farmers with OSD did not appear to have alternative income strategies to compensate and, consequently, they had a lower value of personal wealth indicators (e.g. iron sheet roofing, motorcycle) than those without OSD. One can conclude that although the effect of forest strain onchocerciasis is less dramatic than of the blinding from, the disease poses an important economic threat in the region.

Efficiency of the Swedish pork industry: A farm level study using rotating panel data 1976–1988

This paper investigates the issues of technical efficiency, technical changes and bias in technical change in the Swedish pork industry using rotating panel data. We use a generalized Cobb-Douglas model, where the coefficients are linear functions of time. This allows input elasticities to vary over time. Technical changes and bias in technical change are farm- and time-specific. The model distinguishes farm heterogeneity from technical inefficiency. We use a corrected least squares procedure to estimate the model. The data consists of a rotating panel of 450 pork producing farms with a total number of 1506 observations during the period of 1976–1988. We compare the productive performance of farms by size of farm land and animal stock, and over time. The empirical results show among other things that technical change is found to be positive but rapidly declining during the period 1976–1980 turning into technical regress during the remaining period, 1981 to 1988. The mean technical efficiency is found to be around 91%.

山村地帯に於ける過疎進行の地域格差とその要因に関する一考察

Recognizing the inter-village difference in term of the rate-of-changes of the number of farm households and the size of farmland, this paper attempts to construct a model to find out the factors of maintaining the stability of agricultural production and even rural society in mountain areas. The model takes into consideration the conditions which affect agriculture and forestry such as natural location, the types of various crop composition, the opportunities of off-farm employment within accessible area, the types of diversified agri-business, multiple farming, participation rate in agricultural co-operatives, and meeting frequency in community.The results show that the above-mentioned factors have been playing an important role for the maintenance of farm households and mountain villages, but in the villages where the public projects for the improvement of the production structure of agriculture and forestry were effectively introduced the variables which relate to the production of agriculture and forestry are more significant than that representing the opportunities of off-farm employment. Moreover, the significance of the variables that reflect the potential of ingenuity of farmers and local leaders becomes more notable, while the influence of conventional factors is declining.

Population pressure and land resource depletion in southeastern Nigeria

Though the incidence of population pressure on agricultural land is evident in the Awka-Nnewi region of southeastern Nigeria, there are no precise indices for measuring its intensity and evaluating the spatial pattern. Three related indices, namely, farmland size per capita, fallow index and fragmentation index were calculated from field data to aid in the assessment of the severity of land resource depletion. The merit of each index is discussed together with the procedure of calculating and applying it. By applying these indices singly and in combination the spatial pattern of agricultural land depletion is discussed. The analysis shows that some sections of the Awka-Nnewi region are badly depleted and it would need a combined action of the people and the government to salvage the deteriorating agricultural environment.

The Structure of the Administrative Area of Sendai City seen from the Changes in the Size and Use of Farm Land.

The Structure of the Administrative Area of Sendai City seen from the Changes in the Size and Use of Farm Land.