Within tree variation in anatomical properties of some clones of Eucalyptus tereticornis Sm.

 Within tree variation in anatomical properties of four and half year old grown Eucalyptus tereticornis Sm. clones have been investigated and correlated with specific gravity. Vessel frequency, vessel diameter and fiber length were found to vary significantly from bottom to top with no definite trend. Significant variation exists in all the clones of different parameters. Fiber length was positively correlated with fiber diameter and double wall thickness. Tissue proportions did not show any significant variation from bottom to top. However, highly significant differences have been found between clones among four cell types except fibers. Specific gravity is positively correlated with ray percentage, fiber percentage – vessel percentage ratio and negatively correlated with vessel percentage, while all other anatomical parameters including height and girth have no effect. Received 25 August 1998     

Agroforestry systems and soil surface management of a tropical alfisol:

Soil physical properties were measured on field runoff plots established on a tropical Alfisol in Western Nigeria. Evolution of soil physical properties was assessed over a period of 6 years beginning in 1982 (when soil was cleared off its secondary regrowth) till 1987. Changes in soil physical properties were measured for six systems including plow-till, no-till, contour hedgerows of Leucaena leucocephala established 2- and 4-m apart, and contour hedgerows of Gliricidia sepium established 2- and 4-m apart. Soil physical properties were measured once every year during the dry season following the harvest of second season crops.Over the 6-year period, there were no significant differences in relative contents of textural separates of sand, silt and clay for the surface 0–5 and 5–10 cm layers. The gravel concentration of the surface 0–5 and 5–10 cm layers, however, increased significantly due to plowing and mixing of the surface and subsoil layers. Soil bulk density of 0–5 and 5–10 cm layers, respectively, increased in all treatments from initial values of 1.02 and 1.16 g cm^–3 in 1982 to 1.43 and 1.65 g cm^–3 at the end of cropping cycle in 1986. The maximum increase in soil bulk density was observed for the no-till treatment. Accordingly, there was an increase in penetration resistance of the surface 0–5 cm layer from an average value of 25.3 kPa in 1982 to 210.7 kPa in 1986. The highest penetration resistance (353 kPa) of 5–10 cm layer was recorded for the no-till treatment. In accord with total porosity, the gravimetric soil moisture retention at zero suction was the lowest for the no-till and the highest for a Gliricidia-based system. There were significant improvements in available water capacity (AWC) of the soil by both Leucaena and Gliricidia-based systems. In comparison with the no-till system, increase in AWC by Leucaena- and Gliricidia-based systems, respectively, was 42 and 56 percent by weight for 0–5 cm depth and 12 and 58 percent by weight for 5–10 cm depth. Alterations in p^F curves by agroforestry-based systems were attributed to improvements in soil structure and structural porosity.     

Assessing and Managing Soil Quality for Urban Agriculture in a Degraded Vacant Lot Soil

Following the decline of industrial manufacturing, many US cities have experienced severe population reductions that have resulted in large areas of vacant land. Urban agriculture has emerged as a desirable land use for these spaces, but degraded soils are common. Therefore, we measured soil and plant responses to amendments and management in urban lots where vacant houses had recently been demolished in Youngstown, OH, USA. Soil degradation was observed following demolition activities in the form of compaction (bulk density of 1·5–1·8 Mg m⁻³) and low soil microbial biomass C (21 mg C kg⁻¹ soil). Our split‐plot experiment measured the effects of organic matter (OM) amendments produced from yard wastes and the use of raised beds on soil properties and vegetable crop yields. Two years after their application, OM amendments resulted in significant improvement to a number of soil physical, chemical, and biological properties. Vegetable crop yields were improved by OM amendments in 2011 and by both OM amendments and the use of raised beds in 2012. A soil quality index, developed using factor analysis and the Soil Management Assessment Framework, produced values ranging from 0·60 to 0·85, which are comparable to those reported for rural agricultural soils. All results indicate that urban agriculture can be productive in vacant urban land and that amendments produced from urban yard wastes can improve soil quality at previously degraded sites and increase crop yields for urban agriculture. Copyright © 2015 John Wiley & Sons, Ltd.     

Conservation Effects on Soil Quality and Climate Change Adaptability of Ethiopian Watersheds

This study analyzes effects of soil and water conservation (SWC) on soil quality and implications to climate change adaptation and mitigation in the Upper Blue Nile River Basin of Ethiopia by using the Anjeni watershed as a case study site. Disturbed and undisturbed soil samples were collected from two sub‐watersheds of Anjeni: the Minchet sub‐watershed (with SWC measures) and the Zikrie sub‐watershed (without SWC measures). Soil samples were taken from 30‐cm depth from five representative landscape positions and analyzed following the standard soil lab analysis procedures. The results show that soils from the conserved sub‐watershed had improved quality indicators compared with those from the non‐conserved site. Significant improvement due to SWC measures was observed in the soil hydrological [total moisture content (+5·43%), field capacity (+5·35%), and available water capacity (+4·18%)] and chemical [cation exchange capacity (+4·40 cmol(+) kg⁻¹), Mg²⁺ (+1·90 cmol(+) kg⁻¹), Na⁺ (+0·10 cmol(+) kg⁻¹)] properties. SWC interventions significantly reduced soil erosion by 57–81% and surface runoff by 19–50% in the conserved sub‐watershed. Reduction in soil erosion can maintain the soil organic carbon stock, reduce the land degradation risks, and enhance the C sequestration potential of soils. Therefore, adoption of SWC measures can increase farmers' ability to offset emissions and adapt to climate change. However, SWC measures that are both protective and sufficiently productive have not yet been implemented in the conserved sub‐watershed. Therefore, it is important that SWC structures be supplemented with other biological and agronomic measures in conjunction with soil fertility amendments appropriate to site‐specific conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

Effects of Biochar and Marble mud on Mine Waste Properties to Reclaim Tailing Ponds

The effects of biochar addition in improving soil physical properties are not clearly understood in mining tailings. The objective of this study was to determine the effects of three different types of biochars, in addition to marble mud (MM) and their mixtures, on the structural stability and water retention of mine wastes in Cartagena, Spain. Biochars were produced at 500 °C from pig manure (PM), cotton (Gossipium hirsutum L.) crop residues (CR) and municipal solid waste (MSW). Biochars were added to the mine waste (MW) along with MM and a control (no amendments added). These mixtures were incubated in cores for 90 days (25 °C). PM and CR mixed with MM decreased soil bulk density (from 0 · 98 g cm^‐3 to 0 · 89 and 0 · 84 g cm⁻³, respectively). Amendments had no significant effect on total porosity whereas they increased gas diffusion by 100%, except for MSW. MM improved the plant available water from 0 · 59 to 2 · 56 cm as its combination with biochars, extremely relevant in water scarce climates. The micropores were likely replaced by mesopores when application of PM, CR, MM, and biochars + MM and they improved water retention. Total carbon (TC) and total nitrogen (TN) increased by using biochars and MM and no significant effects were assessed on aggregates. In general, MM mixed with PM and CR derived biochar improved the structural stability and exhibited a strong impact in reclaiming physical quality on mine tailings. Copyright © 2016 John Wiley & Sons, Ltd.     

Effects of dietary nucleotides on growth,survival and metabolic response in whiteleg shrimp,Litopenaeus vannamei against ammonia stress condition

This trial was conducted to evaluate the effects of nucleotides on growth of whiteleg shrimp, Litopenaeus vannamei, and the survival and metabolic responses to ammonia stress test. Experimental diets were as follows: low fish meal diet (LFMD), and four LFMD test diets, each supplemented with 0.1% guanosine monophosphate (GMP), 0.1% inosine monophosphate (IMP), 0.1% mixture of GMP and IMP and 0.1% mixture of GMP, IMP, uridine monophosphate (UMP) and cytidine monophosphate (CMP). The shrimp specimens (initial body weight: 0.99 ± 0.01 g) were randomly allocated into five groups and fed four times daily for 8‐weeks. After the trial, final body weight was recorded and haemolymph was withdrawn for haematological analysis. The shrimp was then challenged with 70 mg/L ammonia (LC50) for 10 days. Survival and haemolymph of the shrimp were taken after exposure to ammonia. The highest growth performance was observed in the shrimp fed diet supplemented with GMP (p < .05), while survival was not influenced by the test diets in the feeding trial. In the ammonia challenge test, the highest survival was observed in the shrimp fed GMP supplemented diet compared to others. The plasma protein, glucose and cholesterol levels increased in all the treatments while triglycerides level decreased post challenge. Cortisol level recovered at day 10th after the challenge. Shrimps fed with nucleotides diets showed higher protein and glucose level compared to control groups post challenge. In general, nucleotides supplemented in the diet enhanced growth, improved stress resistance while modulating the haemolymph metabolites in L. vannamei under ammonia stress.     

Water management in various crop production systems related to soil tillage

Soil tillage, of different types and intensity and performed at different antecedent soil moisture conditions, is an important tool for agricultural water management. Tillage systems have important applications for increasing irrigation efficiency, enhancing the effectiveness of drainage systems, improving water quality, decreasing runoff losses and minimizing soil erosion, increasing runoff losses for water harvesting and supplemental irrigation, and decreasing percolation losses and creating aquatic environments for rice cultivation. The versatility and diversity of applications of tillage systems depend on the choice of tillage techniques. No-tillage methods with residue mulches are useful to conserve soil water. Chisel tillage and subsoiling methods along with ridge-tillage techniques are useful in increasing irrigation efficiency. No-tillage systems are useful in decreasing sediment density and transport of sediment laden pollutants in runoff, and puddling and wet tillage techniques or soil compaction are used in rice cultivation. Finally soil compaction and techniques to increase water repellence are useful for water harvesting for subsequent use in supplemental irrigation.     

中国水仙凝集素基因NTA的克隆、序列分析及蛋白结构预测

凝集素是一种糖专一性结合蛋白,它可以识别不同的糖类。植物凝集素是植物防御系统重要的组成部分。本研究采用RT-PCR的方法,从中国水仙花蕾中克隆了凝集素基因NTA,运用生物信息学方法对其核苷酸序列、编码的氨基酸序列进行分析以及对其蛋白结构进行预测。结果表明,得到的NTA基因全长698bp,包含一个完整的开放阅读框516bp。该基因编码一个含有172个氨基酸的凝集素前体蛋白,该前体蛋白的等电点和分子量分别为5.84和18615.19Da。序列比对结果表明该基因编码的蛋白与其他单子叶植物如杂种水仙、雪花莲、君子兰、石蒜花和孤挺花的凝集素蛋白的同源性较高,分别为84%、80%、77%、78%以及82%。蛋白结构预测表明,中国水仙凝集素蛋白与洋水仙凝集素蛋白在结构上非常相似。对该基因编码的蛋白进行分析及蛋白结构模拟可知,该蛋白含有三个特殊的功能结构域和alpha-D-甘露糖结合表面(QXDXNXVXY)。     

Land configuration and soil nutrient management options for sustainable crop production on Alfisols and Vertisols of southern peninsular India

Land configuration in combination with nutrient management has the potential to improve the productivity of Alfisols and Vertisols in the semi-arid tropics. A four year (1989–1990 and 1992–1993) field experiment was conducted at Coimbatore, India on Alfisols (Chromic Cambisol) to compare the effect of land configuration and nutrient management practices on yield of rainfed sorghum (Sorghum bicolor (L.) Moench). The land configuration treatments were flat bed (FB, the traditional practice), open ridging (OR, ridges, 45 cm apart and 30 cm high) and tied ridging (TR, same as OR plus ridges were tied randomly). The manure and fertilisers were farm yard manure (FYM, livestock excreta plus litter at 5 Mg ha⁻¹) and coir dust (CD, by-product after the extraction of coir from the coconut (Cocos nucifera L.) husk at 12.5 Mg ha⁻¹) in combination with nitrogen (N) and phosphorus (P) fertiliser levels. Tied ridges stored 14% more soil water and produced 14% and 11% more grain and straw yields of sorghum, respectively, than did flat bed. However, crop yield in TR was comparable with OR. Application of CD at 12.5 Mg ha⁻¹ combined with 40 kg N ha⁻¹ and 9 kg P ha⁻¹ was beneficial for more soil water storage and increased yield of sorghum by 7% over FYM at 5 Mg ha⁻¹ + 40 kg N ha⁻¹ and 9 kg P ha⁻¹. In Vertisols (Vertic Cambisols), experiments were conducted for two years (1991–1992 and 1992–1993) to evaluate land configuration practices. The treatments were broad bed furrow (BBF, 120 cm wide bed with 30 cm wide and 15 cm deep furrows on both sides), compartmental bunding (CB, bunds of 15 cm height formed in all the four sides to form a check basin of 6 m × 5 m size), ridging (RD, ridges were formed for each and every row of the crop manually at four weeks after sowing) and FB under sorghum + pigeonpea (Cajanus cajan (L.) Millsp) and pearl millet (Pennisetum glacum (L.) Stuntz) + cowpea (Vigna unguiculata (L.) Walp) intercropping separately. Compartmental bunding stored 22% more soil moisture and increased the yield of sorghum + pigeonpea intercropping than did FB in a low rainfall year. In a high rainfall year, BBF produced 34% and 33% more grain yield of sorghum and pearl millet base crops, respectively, over FB. However, BBF and CB were comparable. Pigeonpea intercrop under sorghum followed the same trend as its base crop, whereas, yield of cowpea differed compared to the pearl millet base crop. Tied ridging and application of manures (CD or FYM) in combination with inorganic N and P fertiliser can increase the soil water storage and yield of crops compared to traditional flat bed cultivation in rainfed Alfisol and related soils of semi-arid tropics. Similarly BBF and CB land configuration practices could be adopted on Vertisols for better water conservation to increase the soil fertility and productivity of intercropping systems.     

Effects of slope length on erosion of some alfisols in Western Nigeria

Erosion was monitored for erosive rainstorms received during 1977 and 1978 from an Alfisol at Ibadan in western Nigeria on bare plowed soil using field runoff plots on natural slopes of 1, 5, 10 and 15% and with 5, 10, 15 and 20 m slope lengths. Equations of the type A = αL^b were computed relating soil erosion (A) to slope length (L).Erosion was affected more by slope gradient than by slope length and was in the order of 1, 17.6, 31.3 and 22.8 for 1977 and 1, 25.5, 53.0 and 62.4 for 1978 for 5, 10 and 15% slope gradients, respectively. For gentle slope gradients of 1 and 5%, slope length had little effect on erosion. During 1978, erosion for 10% slopes was in the order of 1, 1.05, and 1.08 for 5, 10 and 15 m slope lengths, respectively. For 15% slope, however, the soil erosion was in the order of 1, 1.11, 1.51 and 1.60 for 5, 10, 15 and 20 m slope lengths. The mean sediment concentration (averaged over all slope gradients), was 1, 1.27, 1.50, 1.99 for 1977 and 1, 1.61, 2.71, 2.73 for 1978 for 5, 10, 15 and 20 m slope lengths, respectively.