Seventeenth century organic agriculture in China: II. Energy flows through an agroecosystem in Jiaxing region

The energy flows in a seventeenth century agroecosystem in Jiaxing region of eastern China were analyzed on the basis of historical data. The agroecosystem included cropping, mulberry-silkworm, livestock, and fishing systems. In terms of energy, the agroecosystem was sustainable. Human labor provided all the power with inputs of about 3700 hr per hectare of farmland. Most or 70% of the labor was expended in the cropping system. Human and animal manure provided most of the nutrients for crop and mulberry production. About two-thirds of the total manure was used in crop production and one-third in the mulberry plantations. The only fossil energy input was a few hand tools. Approximately 55% of the grain was consumed directly by local residents, about one-third of the grain was used to make an alcohol drink and produce distillers'grains, which was fed to pigs, and only 2% of the grains were exported outside the agroecosystem. About two-thirds of the harvested crop residues were used as household fuel, while the remainder was returned to the field as an organic fertilizer. Pork accounted for 85% and silk cocoons 14% of the total animal products produced. Even though the agroecosystem was generally sustainable in terms of energy, the major environmental problem was that two-thirds of the harvested crop residues were used for household fuel. This reduced nutrient cycling in the system. Insufficient land was available to produce fuelwood;thus, crop residues were the primary source of fuel for the people.     

Assessment of veld conditions with multivariate techniques in mixed bushveld,South Africa

The species composition of the herbaceous layer was surveyed in eight plant communities with a small-quadrat method. Ordination techniques were applied to these data to identify relative homogenous grazing areas, assess the veld condition of each unit and to identify indicator species, based on a grazing gradient. Five relative homogenous grazing areas were identified and should be treated as such for management purposes. The veld in the Nylsvlei Nature Reserve was generally in a good condition due to the low stocking densities of game (≈0.29 animals ha^?1) which have been maintained for many years. Nine indicator species, i.e. Cynodon dactylon, Digitaria eriantha, Ischaemum afrum, Leersia hexandra, Oryza longistaminata, Setaria sphacelata, Sporobolus ioclados, Sporobolus pyramidalis, and forbs, were identified which may be used for future monitoring of veld condition in the different vegetation units.     

Seventeenth century organic agriculture in China: I. Cropping systems in Jiaxing region

The cropping systems of seventeenth century traditional organic agriculture in the Jiaxing region of eastern China required about 2000 hr of labor per hectare for rice production. Rice and related grain crops were produced employing only human power. The input was about 200 times that for most mechanized grain production today. The charcoal or fossil energy input to produce simple hand tools accounted for only 1–2% total energy in the crop systems. Organic wastes including manures, pond sediments, and green manure crops supplied most of the nutrients. Rice yields, ranging as high as 6700–8400 kg/ha, were similar to some of the highest yields today. The energy output/input ratio ranged from 9 for compost-fertilized rice to 12 for green manure-fertilized rice production. These ratios were 2–10 times higher than most mechanized rice production systems of today. Knowledge of the crop and soil system enabled the early Chinese farms to maintain high crop yields and sustain highly productive soils.     

半胱胺促进空怀奶山羊乳腺发育的试验研究

目的：研究半胱胺对空怀奶山羊乳腺发育的影响。方法：选6只空怀奶山羊进行自身前后对照试验。对照期饲喂基础日粮,试验期饲喂基础日粮加CS。结果：与对照期相比,试验期山羊乳腺组织的DNA含量明显升高,RNA含量明显下降,故RNA／DNA值显著下降。试验期血浆GH和PRL水平分别提高61．6％和31．6％。组织学观察发现,对照期乳腺的腺泡很少发育,几乎看不到乳导管;试验期乳腺有明显导管生长和少量腺泡发育。结论：半胱胺能够在一定程度上促进空怀奶山羊乳腺发育。