Energy Use and Output Assessment of Food-Forage Production Systems

An assessment of the energy requirements of different intensive forage production systems was carried out at the Indian Grassland Fodder, and Agroforestry Research Institute, Jhansi. This included assessment of energy use and output for five intensive crop production systems: (1) sorghum (single‐cut)–berseem, (2) cowpea–sorghum (single‐cut)–berseem + mustard–maize + cowpea, (3) sorghum (multi‐cut)–berseem + oats, (4) guar–oats–maize and (5) sorghum (single‐cut)–wheat–fallow. In all the systems, the Napier bajra hybrid (IGFRI‐3) was transplanted in regular plots of 50 m × 13 m. Results revealed that the total annual energy use was highest for sorghum (multi‐cut)–berseem + oats (36 606 MJ ha^?1), followed by sorghum (single‐cut)–berseem + mustard, sorghum (single‐cut)–berseem–cowpea, guar–oats–maize and sorghum (single‐cut)–wheat–fallow (for which values were 31 086, 30 449, 29 867 and 25 956 MJ energy ha^?1, respectively). The high value found for sorghum (multi‐cut)–berseem + oats might be attributable to the multi‐cuts in this system. Energy use by fertilizers represented the major part of the total energy use, amounting to 28–38 % in all treatments, followed by energy used in electricity, machinery, seeds, human labour and farmyard manure (FYM), in case of all with slight increase in input. In sorghum–wheat, energy use by seeds occupied the second position, followed by energy used in electricity, human labour, FYM and machinery/diesel. Pesticides contributed the least energy utilization in all the treatments. Herbicides were used for the control of weeds. Among the five forage production systems, sorghum (single‐cut)–berseem + mustard–maize + cowpea was found to be the most energy efficient, followed by sorghum (multi‐cut)–berseem + oats–sorghum (multi‐cut), sorghum (single‐cut)–berseem–cowpea, guar–oats–maize and sorghum (single‐cut)–wheat–fallow. Sorghum (single‐cut)–berseem + mustard–maize + cowpea increased the fertility of the soil, resulting in a higher percentage of organic carbon, higher availability of nitrogen and optimal balancing of the C:N ratio in the upper layers of the soil. These intensive crop production systems also maintain the optimum microbial population in the crop root zone. The benefit–cost ratio (B:C ratio) for the most energy‐efficient forage production system was 1.37 : 1. However, the highest B:C ratio was found in the sorghum–wheat rotation (1: 1.57).     

Dual inoculation of a woody legume (Centrolobium tomentosum) with rhizobia and mycorrhizal fungi in south-eastern Brazil

The integration of N₂ fixing trees into stable agroforestry systems in the tropics is being tested due to their ability to produce high biomass N and P yields, when symbiotically associated with rhizobia and mycorrhizal fungi. The growth of Centrolobium tomentosum Guill. ex Benth, a native leguminous tree from the Brazilian Atlantic Forest, was assessed with dual inoculation of Rhizobium spp and mycorrhizal fungi under field conditions. Complete fertilization was compared to treatments of inoculation with selected rhizobia strains BHICB-Ab1 or BHICB-Ab3, associated or not to arbuscular mycorrhizal (AM) fungi. The dual inoculation increased the height and growth in relation to the plants treated with rhizobia alone. Plants inoculated with strain BHICB-Ab1 and arbuscular mycorrhizal fungi (AMF) exhibited an increase of 56% dry matter over uninoculated control and nitrogen accumulation was greater than with BHICB-Ab3 inoculated plants. Strain BHICB-Ab1 presented a synergetic relationship with mycorrhizal fungi since the combined inoculation with BHICB-Ab1 enhanced plant height and dry weight more than single inoculation while the growth of BHICB-Ab3 plants was not modified by AMF inoculation. Arbuscular mycorrhizal fungi enhanced plants survival and seemed to favour the nodule occupation by rhizobia strains as compared to the non-mycorrhizal plants. Inoculation with selected rhizobia and AMF improved the growth of C. tomentosum under field conditions. This revised version was published online in June 2006 with corrections to the Cover Date.     

Improved fallows come of age in the tropics

Improved fallows are the deliberate planting of fast-growing species — usually legumes — for rapid replenishment of soil fertility. Improved fallows are rapidly spreading in several regions of the tropics as a sensible way for in situ accumulation of large quantities of N in vegetation and soil, as well as for providing sustainability enhancing services. Research on improved fallows increased after the mid 1980s with the development of what is known as the second soil fertility paradigm, which is based on sustainability considerations. Many lessons have emerged from short-term improved fallows (<5 years duration). These include the diversity of farm sizes where improved fallows are used, the advantage of sequential versus simultaneous systems, the utilization of dry seasons unfavorable for crop production, the comparative advantages of woody versus herbaceous leguminous fallows, the magnitude of N accumulation, the strategic use of N fertilizers, and the importance of P. Other key services provided by fallows include fuelwood production, recycling of nutrients besides N, provision of a C supply to soil microorganisms, weed suppression, Striga control, and improved soil water storage. Natural fallows of non-legume shrubs belonging to the Asteraceae family, collectively called daisy fallows, may provide lessons for the development of improved fallows. The maintenance of genetic diversity in fallows is paramount. The main limiting factor in Africa is clearly the supply of germplasm of improved fallow species. This must be overcome though large-scale seed orchards and nursery development before impact at the scale of millions of farmers can take place.This revised version was published online in November 2005 with corrections to the Cover Date.     

Effect of supplementing Rhodes grass hay (Chloris gayana) with Berchemia discolor or Zizyphus mucronata on the performance of growing goats in Kenya

Twenty growing Small East African goats were used to determine the effects of feeding sun-dried leaves of the browse forages Berchemia discolor and Zizyphus mucronata as supplements to low-quality basal diet, Rhodes grass (Chloris gayana) hay, on voluntary feed intake (VFI), digestibility and growth performance. The grass hay and maize bran were used as a control. The dried leaves were then included at the rates of 15% and 30% of the dry matter intake (DMI). Berchemia discolor had the highest crude protein (CP) content of 195.5 g/kg DM, while Z. mucronata had CP content of 169.5 g/kg DM. The grass hay had the lowest CP content of 50.9 g/kg DM. The browse forages had low fibre content [Neutral detergent fibre (NDF); 257.9-369.5 g/kg DM], while the grass hay had high fibre content (NDF; 713.1 g/kg DM). Goats in the groups supplemented with either of the browse forages had higher total DMI, nitrogen (N) intake and retention and live-weight gains than those in the control diet group. The digestibility of DM and organic matter (OM) was not affected by supplementation, but the CP digestibility increased with supplementation. The use of the browse forages as supplements for goats fed on poor-quality basal diets would enhance the performance of the animals.     

山地红壤冬季牧草引种与鸡脚草喂鹅试验研究

在山地红壤引种冬季牧草鸡脚草、宽叶型一年生黑麦草、牛尾草、白三叶，并利用鸡脚草进行喂鹅试验。引种观测表明几种牧草均适应在福州山区种植，鸡脚草、宽叶型一年生黑麦草、白三叶对鹅适口性很好。鸡脚草喂鹅试验结果表明，经40d饲养，仔鹅平均日增重达43．0g，比饲喂当地野生杂草的对照组有明显的提高，饲料报酬比对照组提高28．6％，在屠体品质方面，也有改善和提高的趋势。     

干旱区苜蓿和沙打旺单混播下土壤水分利用格局的驱动力分析

大田条件下采用生物替代试验对沙打旺和苜蓿单播及混播的一年生人工草地进行了土壤水分利用动态格局调查研究.结果表明,3种密度下土壤水分随生育期变化相似,均呈下降趋势,但随播种密度增大,不同播种方式平均土壤水分利用效率逐渐增大,而2种牧草平均群体水分利用效率比较为混播下苜蓿>单播苜蓿>单播沙打旺>混播下沙打旺.牧草返青后,在中密度下显示出较宽的资源共享生态位,而低密度和高密度显示出稍窄的资源共享生态位.3种密度下整个生育期内苜蓿的相对竞争力均高于沙打旺,其中平均相对竞争力比较为高密度>中密度>低密度,而且随生育期变化苜蓿的相对竞争力持续增强.苜蓿对沙打旺的相对竞争力与混播处理中苜蓿对沙打旺的群体水分利用效率比有显著正相关.由此可见,在苜蓿与沙打旺一年生混播试验中苜蓿竞争力始终大于沙打旺,其中密度效应和水分利用为两者种间关系调节的重要影响因素.2种牧草混播中苜蓿生产力、群体水分利用效率与苜蓿对沙打旺的竞争优势为性状互利关系.因此,旱生环境中苜蓿与沙打旺的水分利用格局可能由2个物种种间竞争关系所驱动的,水分资源利用状况反应了两者对干旱胁迫环境下适应种间竞争的生活史对策.     

草甸草原不同放牧制度群落物质动态及植物补偿性生长研究

在草甸草原家庭牧场比较研究了不同放牧制度对群落物质动态变化规律及植物补偿性生长的影响.结果表明,划区轮牧较自由放牧可提高现存量、生长量、生产力;与对照相比2001年两种放牧制度下群落均表现为欠补偿生长;2003年划区轮牧区群落表现为等补偿生长,自由放牧区群落表现为欠补偿生长;两种放牧制度草群营养物质变化规律基本一致.     

赤峰北部主要野生豆科牧草的植物区系及属种组成特征

对显峰北部野生豆科牧草种质资源进行了调查研究。结果表明,赤峰北部主要野生豆科牧草有１３属２４种,分别占本市野生豆科牧草总属种的５９．１％和２４．２％,灌木类有３属６种,草本有１０属１８种,植物区系以温带成分为主,属于５个分布区４个亚区。属内种系比较贫乏。     

生态学视角下的草地载畜量概念

从防止草地土壤侵蚀这个全新的视角出发,对草地载畜量的确定方法进行了系统的理论探讨,首先讨论了牲畜放特通过直接和间接的方式对草地土壤侵蚀的影响,接着就风蚀和水蚀这两种干旱半干旱区草地最重要最常见的土壤侵蚀方式,探讨了植被有效覆盖度的确定,并在此基础上,给出了牧草可采食率和载畜量的确定方法。     

干旱灌区小麦间作玉米麦后复种绿肥的可持续性分析

[目的]针对干旱灌区传统生产模式的资源利用率和产投比低等问题,研究小麦间作玉米集成麦后复种绿肥的光能利用率、灌溉水生产力及经济效益表现,结合试区常规种植模式,评价不同种植模式的可持续性,对于干旱灌区农业生产的节本增收有重要指导意义.[方法]2018-2020年,在河西绿洲灌区设置田间定位试验,研究了不同种植模式(春小麦...