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Objective management of grazing livestock production systems needs monitoring of forage production at the managerial unit level. Our objectives were to develop a system that routinely estimates forage above-ground net primary production (ANPP) at the spatial and temporal resolution required by farmers in the Pampas of Argentina, and to facilitate adoption of the system by end users as a managerial support tool. Our approach was based on the radiation use efficiency (RUE) logic, which proposes that ANPP is determined by the amount of photosynthetically active radiation absorbed by the canopy (APAR), and the efficiency with which that energy is transformed in above-ground dry matter (radiation use efficiency, RUE). APAR is the product of incoming photosynthetically active radiation (PAR) and the fraction absorbed by the canopy (fPAR). We estimated fPAR as a non-linear function of MODIS normalized difference vegetation index (NDVI). RUE was empirically estimated for the two principal forage resources of the region, yielding the following relations: ANPP = 0.6 × APAR + 12, (R2 = 0.86; p < 0.001; n = 18) for the upland sown pastures, and ANPP = 0.27 × APAR + 26, (R2 = 0.74; p < 0.001; n = 18) for the lowland naturalized pastures, with ANPP in g/m2/60 days and APAR in MJ/m2/60 days. The models were able to predict independent ANPP values with acceptable accuracy. Computational procedures were automated and run in a Relational Data Base Manager System that stored and managed all the information. The system is currently monitoring 212,794 ha in 83 farms and provides monthly ANPP values for the previous month and a history of the last 6 years. The data so generated show ANPP differences between the two major forage resources, considerable variability of a given month’s ANPP among years and paddocks, and contrasting among-farm differences in the efficiency of conversion of ANPP and forage supplements into beef production. The system was well accepted by end users who utilize it mainly for making near real time decisions according to last month ANPP, and explaining results of previous production cycles by incorporating ANPP as an explicative variable. However, there were differences among farmers in the degree of utilization, apparently related to the advisor’s attitude toward this new technology. Our results indicate that (1) forage production of large extensions can be monthly monitored at the paddock level by a small laboratory with capabilities in geographic information systems, and (2) advisors and farmers apply this information to their managerial decisions. 相似文献
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为探讨饲喂苜蓿（Medicago sativa）干草、羊草（Leymus chinensis）和玉米（Zea mays）青贮与单纯饲喂玉米秸秆相比,对育成母羊增重、饲料转化效率和经济效益的影响。选取体重、年龄相近,健康的育成母羊20只,随机分成4组,每组5只,分别饲喂不同种类粗饲料日粮,精粗比为40：60。结果表明：与粗饲料单纯为玉米秸秆（100%）相比,苜蓿干草（50%）+羊草（50%）组日增重提高11.11%,饲料转化效率不明显,增收也不明显;苜蓿干草（33.3%）+玉米青贮（33.3%）+羊草（33.3%）组日增重可提高30.72%,饲料转化效率提高 18.16%,每天每只增收0.54 元;苜蓿干草（50%）+玉米青贮（50%）组日增重可提高83.01%,饲料转化效率提高 40.74%,每天每只增收可达1.91 元。表明,饲喂苜蓿干草（50%）+玉米青贮（50%）时,育成母羊增重、饲料转化效率、以及经济效益都能达到最好的状态。 相似文献
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A number of studies have shown that the rumenic acid (RA = cis-9 trans-11 C18:2 CLA) content of milk fat is usually higher in sheep than in goats, due partly to different dietary regimens. An experiment was conducted with 12 lactating dairy ewes and 12 goats with the objective to compare the two animal species (sheep/goats) fed diet with the same forage/concentrate (F/C) ratio, on their milk fatty acids (FA) profile with emphasis on RA and vaccenic acid (VA) production. The experiment was carried out in three consecutive phases, lasted 3 weeks each, immediately after weaning of lambs and kids. In phase I, the ewes and the goats were fed according to their maintenance and lactation requirements, with 14 kg alfalfa hay, 4 kg wheat straw and 12 kg concentrate the 12 ewes (F/C ratio = 60/40), and with 14 kg alfalfa hay, 4 kg straw and 24 kg concentrate the 12 goats (F/C ratio = 43/57). In phase II, 14 kg alfalfa hay, 4 kg straw and 14 kg concentrate were offered daily to each group of sheep and goats, with a F/C ratio = 56/44. In phase III, all ewes and goats were fed individually with 0.8 kg alfalfa hay, 0.2 kg wheat straw and 0.8 kg concentrate daily with a F/C ratio = 56/44. The results showed that the different F/C ratio between sheep and goats diets, in phase I, changed significantly the milk FA profile, with no significant difference in RA and VA milk fat content between sheep and goats in phase I. In phases II (group feeding) and III (individual feeding), where sheep and goats fed with the same amount of food of the same F/C ratio, the sheep milk fat had higher RA and VA content compared to goats. In conclusion, these findings support the hypothesis that there are species differences, as RA and VA production concerns, which needs further investigation. 相似文献
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刈割和放牧后牧草碳氮动态研究进展 总被引：2，自引：0，他引：2
牧草被利用后生物量和品质的形成取决于再生,刈割或放牧后牧草能否顺利再生、能否形成较优的生物量和品质与残茬和根系中的物质含量变化和分配息息相关.刈割或放牧后,牧草前期再生中需要的碳、氮主要来自 体内贮藏的碳水化合物和含氮物质,后期需要的碳、氮则主要依靠残茬光合碳同化和根系氮吸收来供应.对前人有关刈割或放牧后牧草残茬和根系中的贮藏碳、氮含量和生理功能变化的相关研究进行了综述,试图从牧草被利用后物质含量变化和分配的角度阐述牧草再生机制,并对牧草再生研究的可能方向进行了展望. 相似文献
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Intercropping corn with legumes is an alternative to corn monocropping and is a possible way to reduce the use of inputs, such as herbicides, while maintaining current weed control levels. Two experiments were carried out at each of two sites in both 1993 and 1994. The first experiment investigated the effects of seeding soybean or lupin alone or in combination with one of three forages (annual ryegrass, Lolium multiflorum Lam.; perennial ryegrass, Lolium perenne L.; and red clover, Trifolium pratense L.) on weed control. The second experiment examined the effects of seeding date (simultaneous with corn or 3 weeks later) and number of rows of large-seeded legumes (one or two) seeded between the corn rows, on weed control. Whenever seeding of legumes/forages was delayed, weekly interrow tillage operations were used to control weeds until legume/forage seeding. The density and biomasses of monocot weeds, either on or between the corn rows, were not affected by cultivation or intercropping. The density and biomass of dicot weeds on corn rows were reduced by some intercrop systems. For the various cropping systems tested, the dicot weed biomass and density between corn rows were most affected (in some cases reduced by 73-100% of the weedy control). A more effective dicot weed control was observed in delay seeded treatments, which allowed extra interrow cultivations. Intercrops that included soybean were also more successful at reducing weed populations than those containing lupin. Underseeded forages did not reduce weed biomass or density. 相似文献
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四川低山丘陵区冷季型牧草引种试验(简报) 总被引：1，自引：1，他引：0
我国西南温带和热带过渡区,牧草品种短缺,通过引种评价,很多品种得以推广利用[1,2]。美国南方的自然条件在一定程度上和我国南方类似[3],该地的牧草种植模式值得借鉴。本试验对引自美国的几种牧草进行评价,以补充我国草种资源,解决生产问题。1材料与方法1.1试验区自然概况试验区位于四川省洪雅阳平种牛场(北纬29°53,′东经103°22′),海拔514 m,年均气温16.8℃,7月月均气温25.7℃,无霜期303d,年均降水量1494mm。粘性黄泥土,pH 5.46,有机质含量2.70%,水解N 171.3 mg/kg,有效P 12.5 mg/kg,速效K 43.8 mg/kg。 相似文献
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种草在复垦种植系统工程中的效益 总被引：1，自引：0，他引：1
本文根据1987—1989年在阳泉铝矾土矿区固体废弃物复垦种草试验资料论述了种植多年生豆科绿肥牧草有利于迅速绿化美化矿区,加速生土熟化,改善生态环境,是整治国土的一项有效措施。 相似文献
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试验对6年龄桉树人工林间作禾本科及豆科牧草后的土壤微生物进行研究,结果表明：间作牧草可显著提高林地土壤微生物的生物量、呼吸强度、硝化作用强度及纤维素分解作用强度,且均随着土层深度的加深而降低;其中以间作热研6号珊状臂形草、热研2号柱花草、GC1581柱花草和Mineirao柱花草的土壤微生物生物量最高;热研15号刚果臂形草、热研6号珊状臂形草、杂交臂形草、热研10号柱花草、Mineirao和GC1581的呼吸强度高于CK;热研11号黑籽雀稗、热研10号柱花草、GC1581和热研2号柱花草的硝化作用强度强于CK;热研9号坚尼草、杂交臂形草和热研6号珊状臂形草、热研10号柱花草和热研2号柱花草的土壤纤维素分解作用强度较强。 相似文献
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