天然草地放牧场作为草地的利用终端之一,其管理水平决定着草地健康和牧场生产水平。随着信息技术的发展和生态学研究的定量化、微观化,草地放牧系统模型的研究及其如何指导生产实践已成为现代化草地畜牧业研究的重要方向。牧场管理模型...天然草地放牧场作为草地的利用终端之一,其管理水平决定着草地健康和牧场生产水平。随着信息技术的发展和生态学研究的定量化、微观化,草地放牧系统模型的研究及其如何指导生产实践已成为现代化草地畜牧业研究的重要方向。牧场管理模型作为草地放牧系统模型之一,是草地和家畜生产的决策支持系统(Decision Support System,DSS)。它通过收集草地生长、家畜生产以及管理方式等数据,模拟不同生产管理方式的影响并用以指导生产实践。本文介绍了国内外牧场管理模型的研究现状,并对今后牧场管理模型的发展做出了进一步展望,以期为国内牧场管理模型的研究与应用提供参考。展开更多
Sulphur (S) cycling and implications on S fertilizer requirement in sheep-grazed pastures receiving three levels of S fertilizer at rates of 0, 30 and 60 kg S/hm 2 in 1995 and 1996 were studied using a mass-balance a...Sulphur (S) cycling and implications on S fertilizer requirement in sheep-grazed pastures receiving three levels of S fertilizer at rates of 0, 30 and 60 kg S/hm 2 in 1995 and 1996 were studied using a mass-balance approach which accounted both for S inputs to and outputs from the soil-plant-animal system. Results indicated that S fertilizer increased by 50% of herbage S uptake and 15% or more of S bio-cycling rate in grazing system. The total S recovery of 30 and 60 kg S/hm 2 treatments from 1995 to 1996 was 74.0% and 37.6% respectively. Mineralization of organic S may be an important source of S for pasture when other S sources are low, accounted for 70% of the total S inputs without S fertilizer. The grazing sheep has an important ecological function, the feature of S cycling in grazed pastures was that 90% of herbage S ingested by grazing sheep was returned to soils as excreta. The amount of S released by sheep excreta accounted about 30% of the total released S through S bio-recycling. Loss from soil S leaching beyond the major plant rooting zone was the main S output from grazing system. However, urinary and fecal S losses, including transfer and leaching losses, also affected S budgets of grazing system. It is therefore important to investigate the recycling rate of both urinary and fecal S under field conditions. Based on the mass-balance principle, at least 10 kg S/hm 2 per year may be necessary for sustainable development of grazing system.展开更多
文摘天然草地放牧场作为草地的利用终端之一,其管理水平决定着草地健康和牧场生产水平。随着信息技术的发展和生态学研究的定量化、微观化,草地放牧系统模型的研究及其如何指导生产实践已成为现代化草地畜牧业研究的重要方向。牧场管理模型作为草地放牧系统模型之一,是草地和家畜生产的决策支持系统(Decision Support System,DSS)。它通过收集草地生长、家畜生产以及管理方式等数据,模拟不同生产管理方式的影响并用以指导生产实践。本文介绍了国内外牧场管理模型的研究现状,并对今后牧场管理模型的发展做出了进一步展望,以期为国内牧场管理模型的研究与应用提供参考。
文摘Sulphur (S) cycling and implications on S fertilizer requirement in sheep-grazed pastures receiving three levels of S fertilizer at rates of 0, 30 and 60 kg S/hm 2 in 1995 and 1996 were studied using a mass-balance approach which accounted both for S inputs to and outputs from the soil-plant-animal system. Results indicated that S fertilizer increased by 50% of herbage S uptake and 15% or more of S bio-cycling rate in grazing system. The total S recovery of 30 and 60 kg S/hm 2 treatments from 1995 to 1996 was 74.0% and 37.6% respectively. Mineralization of organic S may be an important source of S for pasture when other S sources are low, accounted for 70% of the total S inputs without S fertilizer. The grazing sheep has an important ecological function, the feature of S cycling in grazed pastures was that 90% of herbage S ingested by grazing sheep was returned to soils as excreta. The amount of S released by sheep excreta accounted about 30% of the total released S through S bio-recycling. Loss from soil S leaching beyond the major plant rooting zone was the main S output from grazing system. However, urinary and fecal S losses, including transfer and leaching losses, also affected S budgets of grazing system. It is therefore important to investigate the recycling rate of both urinary and fecal S under field conditions. Based on the mass-balance principle, at least 10 kg S/hm 2 per year may be necessary for sustainable development of grazing system.
