The impact of increasing farm size and mechanization on rural income and rice production in Zhejiang province,China

Economic growth in China’s agricultural sector lags behind growth in industry and services, creating an ever widening rural–urban income gap. Development of the non-agricultural sectors offers new opportunities for farmers in China’s more advanced provinces such as Zhejiang. Increased income in the urban sector creates markets for new products, and migrating farmers rent their land to those staying. Until now, the prevailing rice-based systems have been managed mainly using manual labour and animal traction, but the larger farms resulting from migration may facilitate, or even require mechanization. In this study, we use a simulation model of the farm household to analyse the effects of increasing farm size and the transition from rice to vegetable production, while also studying the effects of mechanization.     

Soil–landscape relationships in the basalt-dominated highlands of Tigray,Ethiopia

Though knowledge about the distribution and properties of soils is a key issue to support sustainable land management, existing knowledge of the soils in Tigray (Northern Ethiopian Highlands) is limited to either maps with a small scale or with a small scope. The goal of this study is to establish a model that explains the spatial soil variability found in the May-Leiba catchment, and to open the scope for extrapolating this information to the surrounding basalt-dominated uplands. A semi-detailed (scale: 1/40 000) soil survey was conducted in the catchment. Profile pits were described and subjected to physico-chemical analysis, and augerings were conducted. This information was combined with information from aerial photographs and geological and geomorphologic observations. The main driving factors that define the variability in soil types found were: 1) geology, through soil parent material and the occurrence of harder layers, often acting as aquitards or aquicludes; 2) different types of mass movements that occupy large areas of the catchment; and 3) severe human-induced soil erosion and deposition. These factors lead to “red-black” Skeletic Cambisol–Pellic Vertisol catenas on basalt and Calcaric Regosol–Colluvic Calcaric Cambisols–Calcaric Vertisol catenas on limestone. The driving factors can be derived from aerial photographs. This creates the possibility to extrapolate information and predict the soil distribution in nearby regions with a comparable geology. A model was elaborated, which enables the user to predict soil types, using topography, geomorphology, geology and soil colours, all of which can be derived from aerial photographs. This derived model was later applied to other catchments and validated in the field.     

A Soil Temperature/Short-Wave Radiation Growth Model for Butterhead Lettuce Under Protected Cultivation in Flanders

The objective of this study was to provide Flemish greenhouse farmers an accurate growth model for butterhead lettuce, based on two environmental parameters, i.e. soil temperature and short-wave radiation. During two consecutive years, a total of 27 growth experiments were followed up, whereby head fresh weight (at a 14 d interval), soil temperature at 10 cm depth (on a half-hour basis), and short-wave radiation (14 d summation) were measured. Separate Gompertz functions, with either radiation or soil temperature as input variable, accurately modelled growth; but via a combined approach, an almost perfect fit (R² = 0.91) between measured and simulated head fresh weight was obtained. This modelling approach provides lettuce growers a tool for the quantitative estimation of crop weight in relation to changes in soil temperature and short-wave radiation. Weather forecast (radiation) and managerial decisions (soil temperature), now serve as the input data of a scientifically based lettuce growth model.     

Evolution of gaseous hydrocarbons from soil: Effect of moisture content and nitrate level

The production of gaseous hydrocarbons has been studied in a clayey, loamy and sandy soil. The soil samples were incubated under closed conditions at field capacity and under waterlogged conditions. Additions of 100 or 300 μgg^?1 nitrate were made to some of the soil samples. It was found that hydrocarbons were produced in two phases: at the beginning of the incubation period, coinciding with the high microbial activity after rewetting a dry soil and after obtaining anaerobic conditions in the flasks. Under anaerobic conditions, the concentration of methane was higher than the concentration of ethylene, ethane and propane. Methane production was high in the neutral soil, and of minor importance in the acid soils, while ethylene production was important in the soil with the highest organic matter content. Waterlogged conditions were much more favourable for hydrocarbon production than field capacity conditions. The addition of nitrate, in general, decreased hydrocarbon production, especially at 300μgg^?1 for all treatments. In some treatments and for some gases, the influence of 100μgg^?1 was less significant.     

Effect of humic substances on nutrient uptake by herbage and on production and nutritive value of herbage from sown grass pastures

The effect of humic substances on the nutrient uptake, herbage production and nutritive value of herbage from sown grass pastures was studied in six field experiments. Commercial humic substances were applied in combination with mineral fertilizer or slurry, either as a solution (HF liquid; 8·3 kg humic substances ha⁻¹) or incorporated into the mineral fertilizer (HF incorporated; 3·6 to 6·4 kg humic substances ha⁻¹). A series of cuts, ranging from two to five cuts, was taken during the growing season. The general response in herbage production to application of humic substances was an increase in herbage mass of dry matter (DM) at the first cut although this was only significant in two experiments for the HF incorporated treatment. Total herbage production of DM over the growing season, however, was similar for treatments with or without application of humic substances. The overall effect of HF incorporated and HF liquid on the herbage mass of DM at the first cut across the experiments was calculated using a meta-analysis technique and it was shown that there was a significant proportional increase of 0·14 ( P  <   0·05) with the HF incorporated treatment and a non-significant increase of 0·08 with the HF liquid treatment compared to the control treatment. The nutritive value of the herbage at the first cut was similar across all treatments. In general nitrogen, phosphorus and potassium uptake at the first grass cut was higher after application of humic substances but only in one experiment was this increase statistically significant.     

The environmental yardstick for pesticides: a practical indicator used in the Netherlands

The environmental yardstick for pesticides has been developed as a tool for farmers to select pesticides with the least environmental impact and to quantify the impact of their use at the crop/farm level, regional level and national level. For each pesticide the yardstick assigns environmental impact points for the risk to water organisms, the risk of groundwater contamination and the risk to soil organisms. It is presently used in the Netherlands as a management tool for farmers and technical consultants, as a tool for monitoring the environmental performance of farmers, as a tool for setting standards for ecolabels and as a policy evaluation tool.