Land Equivalent Ratio of Groundnut-Fingermillet Intercrops as Affected by Plant Combination Ratio,and Nitrogen and Water Availability

Abstract

Field experiments were conducted to characterize intercropping advantages in groundnut-fingermillet intercrop in relation to crop combination ratios, soil moisture and nitrogen (N) availability. Three intercrops in 1 : 2, 1 : 1 and 2 : 1 alternating rows of groundnut and fingermillet were examined for their growth and yield in comparison with their respective sole crops in 1996. The effect of well watered (W) and water stressed (D) conditions on the intercropping advantage was also examined for 1 : 1 intercrops in 1995 and 1996. Fertilizer N was applied at the rate of 20 kg ha^?1 in 1995 and 50 kg ha^?1 in 1996. The total above-ground biomass (DM) and its land equivalent ratio (LER) were highest in the 1 : 1 combination ratio. The DM production of intercropped fingermillet was higher in 1996 with higher N than in 1995 with low N application, while those of groundnut were similar in both years. The intercropped groundnut exhibited significantly higher DM production after the fingermillet harvest. The LERs in grain yield were higher in 1996 (1.43 under W and 1.45 under D), than in 1995 (0.87 under W and 1.22 under D). Also, LERs were consistently higher under D than W conditions. Water stress severely reduced the leaf area index (LAI) of fingermillet at a low N, especially in the later stages, whereas higher N alleviated the water stress effect. A close linear relationship was observed between LAI and leaf area (LA) per unit leaf N both for groundnut and fingermillet, with intercrops producing larger LA per unit leaf N than sole crops. Intercropping maintained higher ability in leaf net photosynthesis and transpiration of groundnut up to later stages, and significantly reduced water evaporation from the soil surface under the canopy than sole cropping of fingermillet. These results suggest that three processes associated with the intercropping yield advantages in the groundnut-fingermillet intercrop; 1) higher leaf photosynthesis and vigorous growth of groundnut after the fingermillet harvest, 2) higher LA production per unit N and 3) efficient water use. In conclusion, interspecific shading was considered to be the key mechanism associated with these processes, leading to the intercropping advantages. The degree of the interspecific shade and its effect on growth and yield depended on the available soil N and water.     

4种土壤对紫穗槐萌发及生长的影响

[目的]研究不同土壤对紫穗槐萌发及生长的影响。[方法]运用室内栽培的方法,测定了紫穗槐在沙土、山坡土、黏土、森林土中的发芽、生长情况。[结果]不同土壤中紫穗槐发芽势和发芽率表现依次为沙土>山坡土>黏土>森林土。主根生长最好的是森林土。森林土的侧根生长最好,山坡土次之,然后是黏土和沙土。下胚轴在森林土的生长最好,在沙土的生长最差。沙土和黏土中紫穗槐根的生物量最好,并在第12天的时候开始就明显高于其他土壤。4种土壤中的下胚轴生物量都差不多,以森林土的较高,而山坡土的积累的干重较多。叶的干重以沙地的最高。[结论]紫穗槐在沙土中的发芽率最高,在森林土中的生长量最大。     

温室条件下巨龙竹和马来甜龙竹的早期生长表现

于温室内移植巨龙竹和马来甜龙竹实生苗进行培育,调查实生苗的保存率和发笋率,以及实生苗和新笋的高度、叶片数、健康状况和枝条的生长表现。结果表明,巨龙竹和马来甜龙竹的保存率分别为7.3%和38.5%,差异极显著;发笋率分别为66.7%和8.1%,差异也达显著水平。实生苗的高度、叶片数分别为11.3cm、3.1片和11.6cm、3.4片,差异不显著,但2竹种的健康状况之间(2.9级和4.7级)差异显著。新笋的高度、叶片数和健康状况分别为10.1~16.1cm、3.9~4.4片和4.8级,枝条的长度、叶片数和健康状况分别7.3~8.8cm、2.6~2.7片和4.7~4.8级,所有调查指标2竹种间均不存在显著差异。     

恒定加热量时热油管道工作特性研究

通过对热油管道工作特性的研究,发现在加热站加热量恒定时热油管道存在临界输量,当输量小于临界输量时,管道运行将进入不稳定工作区。对恒定加热量管道临界输量的影响因素进行了分析,指出总传热系数降低、加热量的增大和加热站上游来油进站温度升高都将使恒定加热量管道临界输量降低。     

温度、盐度和光照强度对鼠尾藻氮、磷吸收的影响

在实验室条件下,研究了不同的温度和盐度组合,温度和光照强度组合对鼠尾藻(Sargassum thunbergii)氮、磷吸收速率的影响.结果表明,上述3个环境因子对鼠尾藻氮、磷吸收速率均有显著影响.其中,温度和盐度对鼠尾藻氮、磷吸收速率有极显著影响(P<0.01),二者交互作用也极显著(P<0.01).在盐度20、温度25℃条件下和盐度30、温度30℃条件下,鼠尾藻对氮有较高吸收速率,分别为11.26μmol/[g(dw)·h]和11.01 μmol/[g(dw)·h];在盐度40、温度15～30℃范围内对磷的吸收速率较大,达到1.5μmol/[g(dw)·h]以上.温度和光照对鼠尾藻氮、磷吸收速率均有极显著影响(P<0.01),二者交互作用极显著(P<0.01).在温度15℃和光照强度140～180μE/(m2·s)以及温度20～25℃和光照强度60～100 μE/(m2·s)条件下,鼠尾藻对氮有较高吸收速率,均在9.60 μmol/[g(dw)·h]以上;在温度25℃和光照强度60μE(m2·s)条件下,鼠尾藻对磷的吸收速率达到最大,为1.30 μmol/[g(dw)·h].本研究结果表明,鼠尾藻总体上对水体中的氮、磷均具有较高的吸收速率,且能较好地同时吸收NH4+-N和NO3--N,显示了它对海水环境中营养盐具有较强的吸收能力.     

Soil Colloidal P Release Potentials under Various Polyacrylamide Addition Levels

Anionic polyacrylamide (PAM) can prevent soil erosion, but its effect on fine particulate phosphorus (P), such as colloidal P, has not been thoroughly examined. The effects of PAM on the release potentials of water‐dispersible colloids (WDC) and total P, molybdenum‐reactive P (MRP), and molybdenum‐unreactive P (MUP) in the colloidal and truly dissolved phases (i.e., TP_coll, MRP_coll, MUP_coll, TP_truly, MRP_truly, and MUP_truly) from six soils across South China were tested in this study. The results showed that the release potentials of TP_coll in the control treatments were 6·9–46·1 mg kg⁻¹ and generally highest in sandy loam soil. Following low (12·5 kg ha⁻¹), middle (25 kg ha⁻¹), and high (50 kg ha⁻¹) levels of PAM application, the release potential of TP_coll decreased by 41·7, 63·2, and 77·4% compared to the control group, respectively. Additionally, PAM may trigger MRP_coll and TP_truly releases in sandy loam and/or silt soils, and for most soils, MRP_truly and MUP_truly showed the highest release potentials at middle or high PAM levels. A significant PAM application level by soil site interaction for the release potentials of WDC and colloidal P was observed. Multiple linear regression showed that the PAM rate combined with soil sand content can successfully predict the release potentials of WDC (R² = 0·552, p  < 0·001) and TP_coll (R² = 0·738, p  < 0·001). Our results suggest that PAM can effectively reduce the loss of soil colloids and colloidal P, while its effects are related to both application level and soil texture. Copyright © 2017 John Wiley & Sons, Ltd.     

Influence of forest tree species on reclamation of semiarid sodic soils

Tree plantation is a proven strategy to improve the salt‐affected soils. However, the efficiency of trees to reclaim the soil varies from species to species. This study was therefore, carried out with the objective of assessing the efficiency of 3‐yr old plantations of Prosopis juliflora (Swartz) D.C. (Mesquite), Eucalyptus tereticornis Sm. (Forest Red Gum) and Dalbergia sissoo Roxb. Ex. D.C. (Indian Rosewood) to improve the sodic soil characteristics in Sultanpur districts of Uttar Pradesh, India (26°10′–26°23′N, 81°50′–82°5′E). Soil samples collected from six depths; 0.0–0.1, 0.1–0.3, 0.3–0.6, 0.6–0.9, 0.9–1.2 and 1.2–1.5 m below the surface, were analysed for chemical and physical properties by following standard methods. The infiltration rate (IR) was determined by double concentric infiltrometer and the permeability by constant head permeameter. The trees were measured for their girth at breast height (at 1.33 m from ground) and crown area within a 100 × 100 m sector at each of the sites selected. There were decreases in soil pH (from 10.06 to 9.64) and exchangeable sodium percentage (from 70.6 to 26.9) at the P. juliflora plantation relative to the E. tereticornis and D. sissoo plantations. The organic carbon and nitrogen content increased from 2.0 and 0.18 g/kg to 3.9 and 0.45 g/kg under P. juliflora at the surface (0.0–0.1 m) layer. There was also more exchangeable Ca²⁺, Mg²⁺and K⁺ at exchange sites and a reduction in exchangeable Na⁺ 3 yr after establishing the plantations. There was a significant decrease in surface soil (0.1 m) bulk density from 1.66 to 1.37 (t/m³) but an increase in porosity from 41.2 to 46.3% and water holding capacity from 4.3 to 4.8 g/kg. The IR and soil permeability also increased after 3 yr of tree growth. Prosopis juliflora proved more effective than E. tereticornis and D. sissoo in its ability to enrich a sodic soil with organic matter and establishing better soil–water characteristics.     

大豆缺蔸效应及在品种区域试验中应用的研究

利用一个主茎型和一个分枝型品系，研究了大豆在不同长度断条下的缺蔸效应。结果表明，分枝型大豆的缺蔸效应大于主茎型大豆，随着断条长度的增加，断条行和相邻全苗行的缺蔸效应均增大。分析了大豆品种区域试验中产生缺蔸效应值，建立了不同类型品种在不同断条方式下的断条长度与实际补偿长度的回归方程。用此方程即可对品种或其它小区试验中的缺蔸效应进行校正。     

水稻机插秧的育苗播种量研究

为提高水稻机插秧的质量,对水稻培育壮秧的影响因素进行分析,并以盘锦地区常用的水稻手扶式插秧机为例,对育苗播种量进行计算,结合实践经验,总结适宜盘锦地区水稻育苗的播种量以及播种作业原则。     

果蔬型果肉饮料的生产及稳定性试验

 介绍了复合果蔬果肉饮料的生产工艺,比较了果胶酶处理对液化率的影响,并对几种稳定剂单独或混合使用的效果进行了试验.结果显示,果胶酶处理山楂、胡萝卜其液化率分别比对照提高32.50%和14.52%.各种稳定剂中,单独使用以0.05%～0.10%黄原胶效果最好;混合使用以0.05%～0.10%CMC+0.05%琼脂和0.05%CMC+0.05%～0.10%黄原胶效果最好.