Production of Pearl Millet Irrigated with Different Levels of Brackish Water and Organic Matter

ABSTRACT

The objective is to determine the growth, yield and chemical characteristics of pearl millet irrigated with different levels of brackish water and organic matter in two cultivation cycles. The experimental design was randomized blocks in a 4 × 4 factorial arrangement, composed of 4 levels of brackish irrigation (25, 50, 75 and 100% evapotranspiration), 4 levels of organic matter (0, 15, 30 and 45 t ha^?1) with 3 repetitions. Along two cultivation cycles, pearl millet crop was analyzed for: plant growth variables, fresh and dry mass production, water-use efficiency, and chemical composition. There was significant interaction between applied water levels and organic matter for lignin in the 2nd cut (P < .05). The number of leaves, number of dead leaves and fresh mass production were influenced by the isolated effect of brackish water levels in cut 1 (P < .05). In turn, fresh mass production, dry mass production, plant height, leaves length, panicle length, fresh mass production, crude protein and ether extract were influenced by the isolated effect of saline water levels in the 2nd cut (P < .05). Growth, biomass production and chemical composition variables in second cut are positively influenced by different brackish irrigation levels under low rainfall conditions.     

Nitrogen Fertilization on Pearl Millet and Guinea Grass: Phytomass Decomposition,Cellulose, Lignin,and Nutrients Release

ABSTRACT

Nitrogen (N) anticipation in cover crops, besides increasing the accumulation of dry weight and nutrients, may favor the subsequent crop by increasing the availability of N. However, N can alter the decomposition of phytomass, which could reduce the beneficial effects of cover crops. The objective of this study was to evaluate the decomposition rate and nutrients release from Pennisetum glaucum and Panicum maximum syn. Urochloa maxima as a function of N fertilization. A randomized blocks design with four replicates, constituted by four treatments (pearl millet with N, pearl millet without N, guinea grass with N and guinea grass without and six sampling times (0, 14, 34, 41, 51 and 68 days after management (DAM)). The pearl millet produces more shoot dry weight than guinea grass, and the N fertilization increases the amount of dry weight for both species, but does not alter the decomposition rate. Pearl millet accumulates and releases to the soil large amounts of nutrients followed by guinea grass, regardless of N fertilization. N fertilization increases the amount of N accumulated and accelerates the release of N into the soil. The maximum release rates occur in the period of 0–14 DAM, more intensely with the N fertilization for the N.     

Effects of Algal Fibre and Perlite on Physical Properties of Various Soils and on Potato Nutrition and Quality on a Gravelly Loam Soil in Southern Norway

Large quantities of seaweed are harvested world-wide for industrial processing, but significant amounts of by-product remain unused and may cause environmental pollution if returned to the sea. Its potential for use in agriculture is therefore of interest. Algal fibre waste from a large alginate extraction plant in Norway was studied with respect to its potential both for soil physical amelioration and as a nutrient source for potatoes. The material contained perlite, itself a wellknown growth substrate, as this was used to filter the fibre in the factory. The effects on soil moisture retention and aeration properties of incorporating up to 80% fibre waste or pure perlite were studied on five widely contrasting soil types. The algal fibre waste had similar effects to pure perlite on soil aeration and on the proportion of water held at low soil moisture tension. It had, however, a far greater effect on moisture retention at higher tension levels. Plant-available water increased by 3.6 vol.% when 10% by volume of fibre was incorporated, as against 1.2 vol.% with the same volume of pure perlite. The effects were similar in all soils. The effect on potato growth and quality of spreading 20 or 40 Mg ha -1 of algal fibre was studied by comparison with the use of various amounts of compound nitrogen- phosphorus-potassium (NPK) fertilizer. The algal fibre contained large amounts of plant nutrients. In the absence of fertilizer, potato yield increased by 30% and 70% with the use of 20 and 40 Mg ha -1 , respectively. These increases declined to 7% and 17% at the highest rate of fertilizer application (120 kg N, 55 kg P and 187 kg K ha -1 ). The effect of 10 Mg ha -1 algal fibre was equivalent to that of 20-25 kg N in compound fertilizer. Algal fibre had little effect on soil contents of available P, K, calcium and magnesium, but the level of sodium rose sharply. Electrical conductivity did not, however, rise excessively. A considerable amount of mineral N remained in the soil after harvest, but most was lost to leaching before the following year's ryegrass crop could make use of it.     

Soil Sulfur Forms in Relation to Physical and Chemical Properties of Midhill Soils of North India

Sulfur (S) availability in soils of agriculturally cultivated locations in the intermediate midhill zone of the Jammu region of India is a major concern. The total S content ranged between 193 and 774 mg kg^?1. The organic S and nonsulfate S were relatively higher and contributed on average 49.05 and 46.71% of total S, respectively. Inorganic sulfate S contributed least to the total S (0.93 to 11.98%), water‐soluble S from 2.21 to 14.82%, and adsorbed S from 7.15 to 50.26%. All the forms of S except adsorbed S correlated positively and significantly with organic carbon content of soils. The multiple regression analysis revealed that the organic carbon content had greater impact on different S forms followed by clay content. Among different forms of S, total S was correlated positively and significantly with organic S (r = 0.983??) and nonsulfate S (r = 0.980??).     

Diffusion of Zinc as Influenced by Physical and Chemical Properties of Soils

The self diffusion coefficients of zinc (D_aZn), determined by half cell technique, were found to be greatly influenced by variations in soil characteristics such as volumetric moisture content, bulk density, temperature, carrier zinc concentration and soil pH. The D_aZn values showed exponential decrease with increase in soil pH but with increasing volumetric moisture content, D_aZn values showed logarithmic increase. The highest D_aZn value was obtained at a compaction of 1.50 g/cm³. Increase in temperature from 5°C to 30°C showed 4 to 20 times increase in D_aZn values. An attempt was made to study the relationship between soil characteristics and D_aZn values for 87 illitic soils differing in physical and chemical properties. The simple and multiple correlation coefficients did not account for more than 21 per cent of variations indicating that D_aZn values cannot be predicted accurately from soil properties.     

山地酿酒葡萄园土壤理化性质分析

对陕西省渭北高原山地3个不同海拔高度酿酒葡萄园0 ～ 60 cm土层土壤的理化性质进行了研究.结果表明:各葡萄园土壤pH均在8.0左右,属碱性土壤;土壤有机质和N、P、K等大量元素含量偏低,各种微量元素除了B含量很低以外,其他元素均含量丰富;各葡萄园土壤理化性质差异很大,从整体上看海拔最低点的最好.土壤养分中速效N、P、K含量与黏粒(＜0.002 mm)含量之间呈显著的正相关,与粉粒(0.002 ～ 0.02 mm)含量之间呈显著的负相关.     

Physical and Chemical Properties of Substrates to Cultivate Seedling of Citrus Rootstocks

Abstract

An experiment was carried out to assess the physical and chemical evolution of three substrates and their relation to the vegetative development of seedlings of citrus rootstock, cultivated in containers. The experiment was carried out in greenhouse conditions on 27 September 2001 and continued until 120 days after sowing. The experimental design was randomized block in a split‐plot scheme. In the plots, there were tested substrates: two of them were specialized for horticulture (commercial 1 and 2) and a mixture (turf plus carbonized rice husk). In the subplots, there were four citrus rootstocks (Trifoliate orange, “C13” Citrange, “C37” Citrange, and “Rangpur” Lime). The main results showed that the physical characteristic of the substrate that had undergone the most modification during cultivation was the remnant water; the chemical characteristics of the substrate were determined for the proper development of the rootstocks, with high salinity being harmful. The nutrient availability, before and after cultivation, must be adjusted to the capacity of each of the citrus rootstock to absorb.     

不同耕作模式对稻田土壤理化性质及经济效益的影响

为研究不同耕作模式对土壤理化性状和作物经济效益的影响,对皖南地区4种典型耕作模式(单季稻种植、油稻轮作、麦稻轮作、烟稻轮作)的土壤和作物产量进行了研究。结果表明:与单季稻种植相比,轮作显著降低了土壤含水量;麦稻轮作和烟稻轮作土壤体积质量显著增加,孔隙度显著降低;麦稻轮作土壤有机质和碱解氮含量分别显著降低35.8%和47.8%;烟稻轮作土壤速效钾含量显著增加68.2%,速效磷含量提高109.5%。油稻轮作和烟稻轮作总产值比单季稻种植分别显著增加35.3%和155.5%。为解决轮作对土壤的不良影响,要注重增施有机肥和秸秆还田以改善土壤体积质量和孔隙度;麦稻轮作应重点解决土壤p H降低的问题;烟稻轮作要减少烟后晚稻的磷肥和钾肥施用量。总体而言,油稻轮作和烟稻轮作是皖南地区维护农田土壤肥力,促进农业可持续发展,实现农业增产增收的重要耕作模式。     

Impact of Digestate Application on Chemical and Microbiological Properties of Two Different Textured Soils

Agricultural application of anaerobic digestates can play an important role in plant nutrition. The effects of digestate treatment were studied in pot experiments, using sandy and loamy textured soils with distinct characteristics. Three different treatments were studied and compared: control, digestate, and irrigation treatments. Nitrogen loading was calculated on the bases of the digestate analysis. The same amounts of digestate and irrigation water were applied in the different treatments before sowing and at the V4–V6 stages of maize. Besides the conventional soil chemical analysis, invertase, dehydrogenase, catalase, and the abundance of some cultivable microbes were measured in two consecutive years. According to our results, irrigation and digestate treatments had greater impact in the case of sandy soils than in loamy textured soils. Digestate provides more effective phosphorus and potassium sources than nitrogen. Based on the results of discriminant analysis, the digestate application had a greater influence on soil chemical properties, followed by microbiological parameters.     

Impact of Sewage Sludge Compost Utilization on Chemical Properties of Olive Grove Soils

Field experiments were conducted for four years, between 1998 and 2002, in two olive grove soils of adult olive orchards (Olea europaea L. cv. Cornicabra) in a clay loam soil in Seseña (Toledo, Spain) and in a sandy loam soil in Aranjuez (Madrid, Spain). There were four treatments, sewage sludge compost (SSC), sewage sludge compost plus urea (SSC+U), urea (U) and control (C). Each treatment was replicated four times and two depths were studied (0-15 and 15-30 cm). Once a year, before spreading sewage sludge compost, soil samples were taken at depths of 0 to 15 cm and 15 to 30 cm. Organic matter, total Kjeldhal nitrogen, phosphorus availability, pH, and electric conductivity were measured. No differences were found between treatment on organic matter and electric conductivity after four years of application of sewage sludge compost to two olive grove soils. In relation to nitrogen content, sewage sludge compost, only in Seseña, produced higher nitrogen soil content than the traditional urea treatment. Sewage sludge compost applied on olive grove soils improved the Phosphorus availability for the olive tree. In Aranjuez, the use of sewage sludge compost increased the pH of the soil with respect to Urea and Control plots. In Seseña, the reverse effect was found.     

Impact of Deficit Irrigation on Maize Physical and Chemical Properties and Ethanol Yield

The objective of this research was to study the effect of irrigation levels (five levels from 102 to 457 mm of water) on the physical and chemical properties and ethanol fermentation performance of maize. Twenty maize samples with two crop rotation systems, grain sorghum–maize and maize–maize, were harvested in 2011 and evaluated at the Kansas State University Southwest Research‐Extension Center near Garden City, Kansas, under a semiarid climate. Results showed that maize kernel weight, density, and breakage susceptibility decreased as irrigation level decreased. Starch contents of maize samples grown under a low irrigation level were approximately 3.0% lower than those under a high irrigation level. Protein contents ranged from 9.24 to 11.30% and increased as irrigation level decreased. Maize flour thermal and rheological properties were analyzed by differential scanning calorimetry and the Micro Visco‐Amylo‐Graph‐U device. Starch gelatinization temperature increased significantly as irrigation level decreased, whereas starch pasting viscosity decreased as irrigation level decreased. Free amino nitrogen (FAN) was significantly affected by irrigation level: it increased as irrigation decreased. Ethanol fermentation efficiency ranged from 90.96 to 92.48% and was positively correlated with FAN during the first 32 h of fermentation (r² = 0.645). Deficit irrigation had a negative impact on ethanol yield. The maize with lower irrigation yielded about 4.0% less ethanol (44.14 mL/100 g of maize) than maize with high irrigation (45.92 mL/100 g of maize). Residual starch contents in the distillers dried grains with solubles were in a range of 0.80–1.02%. In conclusion, deficit irrigation had a significant effect on physical properties, chemical composition, ethanol yield, and fermentation efficiency of maize.     

陕北石油污染对土壤理化性质的影响

为了研究石油污染对土壤理化性质的影响,对安塞县8个类型油井井场周围土壤中的石油烃含量和理化性质进行分析测定。结果表明,井场周围土壤石油烃含量变化范围为0.08~71.49 g/kg,其中井场外0~5 m区域和5~20 m区域内土壤污染严重。石油污染导致土壤含水率、pH值、硝态氮、速效磷、全钾和速效钾含量显著降低,容重、有机质和铵态氮含量显著升高,全氮和全磷含量无显著变化;石油污染土壤中的石油烃含量与含水率、容重、有机质、铵态氮、速效磷和速效钾均呈极显著相关,与pH值和全钾呈显著相关,与全氮、硝态氮和全磷无显著相关关系。     

污水灌溉对苜蓿生长下土壤部分理化性质的影响

通过盆栽试验研究了污水、再生水等不同灌溉水质对苜蓿三次刈割后土壤部分理化性质的影响。结果表明:相对于清水灌溉,污水及再生水处理能显著降低土壤pH值,增加EC值。第二次刈割时污水、再生水处理与清水相比土壤无机氮含量分别增加了63.59%和35.02%,第三次刈割时分别增加了82.18%和30.72%。与清水灌溉相比,污灌处理土壤Cd含量在三次刈割中分别增加了33%,117.65%和138.89%,再生水灌溉处理在三次刈割中分别增加了13.33%,64.71%和61.11%。根据《土壤环境质量标准》进行土壤重金属污染评价表明,在本试验期间各灌溉水质处理未引起土壤Pb污染,但未经处理的污灌处理造成了Cd污染。本研究初步说明污水采用混灌与轮灌方式可适当减缓其不利效应;再生水可作为苜蓿的灌溉用水,但其长期效应仍需进一步深入研究。     

新型肥料对棉花产量及土壤物化性质的影响

为了探究PPMn型水溶肥混合棉粕腐植酸肥施用对棉田土壤和棉花产量的影响,通过红外光谱和扫描电镜分析两种新型水溶肥的官能团特征和外观特征,并利用田间小区试验研究了两种新型水溶肥对棉田土壤物理性质及团聚体、棉花产量和肥料利用率的影响。结果表明:施用棉粕腐植酸肥(H)、PPMn型水溶肥(P)和两种新型水溶肥混合(HP)对改善土壤物化结构和提升棉花产量均优于常规水溶肥(S)和不施肥(CK),其中HP处理效果最好。HP处理使土壤容重降低8.15%,土壤孔隙度增加7.49%,有效降低了0.25mm土壤团聚体所占比例,显著提升氮磷钾的农学利用效率,棉花产量相对于其他处理增加7.5%~41.0%。     

不同土地利用方式对山东滨海盐碱土理化性质的影响

山东滨海盐碱土壤盐分高、养分低、结构差等问题严重影响了该地区的农业发展,因此有效开发和利用该地区土地对其农业增产增收至关重要。以东营市垦利县四种土地利用方式（荒地、草地、耕地、林地）为研究对象,探讨不同土地利用方式对滨海盐碱土基本理化性质、团聚体稳定性的影响。结果表明：（1）土壤的电导率（EC）和水溶性K+、Na+含量均表现为荒地>耕地>草地>林地,且荒地的EC和Na+含量显著高于其他样地;（2）土壤的全氮（N）和总有机碳含量（SOC）表现为林地>草地>耕地>荒地,各土壤0.25~2 mm粒级的水稳性团聚体的SOC最高;（3）林地的机械稳定性平均质量直径（MWD）和> 0.25 mm的机械稳定性团聚体含量（R0.25）显著低于其他样地;（4）荒地的水稳性平均质量直径（WMWD）和> 0.25 mm的水稳性团聚体含量（WR0.25）显著低于其他样地;（5）团聚体破坏率（PAD）依次表现为荒地>耕地>草地>林地。扫描电镜（SEM）结果显示草地、耕地和林地中>2 mm水稳性团聚体的表面和内部有较明显的颗粒、孔隙及黏结物质。Pearson相关分析表明,机械组成与MWD、R0.25存在显著相关性;PAD与水溶性Na+含量、0.25~2 mm组分水稳性团聚体SOC存在极显著相关性。不同土地利用方式对土壤的物理、化学和力学性质有不同的影响。草地和林地土地利用方式对滨海盐碱土壤理化性质的改良效果均显著,林地具有更高的碳储量及团聚体水稳性,但机械稳定性较低。研究结果可为滨海盐碱地区土地利用的合理规划与可持续发展提供参考。     

降雨条件下云南红土理化特性对坡面侵蚀的影响研究

针对不同初始状态的云南红土,在一定雨强、坡度、坡长条件下,研究红土理化特性对坡面侵蚀的影响。采用人工模拟降雨方法进行试验研究,运用Excel分析试验数据。结果表明:(1)红土颗粒组成中黏粒含量对降雨作用下的红土坡面侵蚀影响显著,当黏粒含量增加8.1%时,其侵蚀模数则减小25.8g/(m~2·h);(2)红土初始含水率偏离最优含水率越远,红土侵蚀模数越大。当红土初始含水率从接近最优含水率的24.6%增加到36.5%时,侵蚀模数从110.4g/(m~2·h)增加到121.3g/(m~2·h);(3)在初始干密度为1.0,1.1,1.2,1.3,1.4g/cm~3条件下,红土侵蚀模数呈先增大后减小的二次曲线变化趋势(R~2=0.927)。初始干密度在1.1~1.2g/cm~3之间,红土侵蚀模数存在极大值[126g/(m~2·h)];(4)降雨作用使坡面红土铁铝氧化物含量减少,接近坡脚处Fe_2O_3含量从初始状态的8.591%减小到8.143%,Al_2O_3含量从初始状态的22.242%减小到20.967%;而坡内红土铁铝氧化物含量则随深度增加,坡体中段坡内的Fe_2O_3含量增加0.407%,Al_2O_3含量增加0.861%。降雨作用改变了红土理化特性,而红土理化特性的变化会对红土坡面侵蚀产生显著影响。     

花岗岩风化土物理特征曲线间的相关性研究

花岗岩风化壳水分及收缩特性的研究是花岗岩土体稳定性评价及侵蚀机理研究的基础。通过Van Genuchten(VG)模型对不同风化程度的花岗岩土壤的颗粒累积分布、土水特征曲线和收缩特征曲线进行拟合,分析曲线拟合参数间以及这些参数与基本物理性质间的线性及非线性相关关系。结果表明:VG模型可以很好地用于不同风化程度花岗岩风化土的颗粒组成、土水特征与收缩特征的拟合与预测;曲线拟合参数间具有一定的线性相关关系;曲线拟合参数与基本物理性质间具有一定的线性相关关系,其中土水特征曲线参数与土壤质地以及容重线性相关性较高,收缩特征曲线物理参数与基本物理性质间的线性相关性较收缩特征曲线其他参数高。此外,曲线拟合参数间以及这些参数与基本物理性质间具有一定的非线性相关关系,而关系多为二次、三次非线性相关。根据花岗岩风化土颗粒组成状况及其基本物理性质对其水分特征曲线及收缩特征曲线进行预测具有一定的可行性。     

Soil Properties and Maize Growth in Saline and Nonsaline Soils using Cassava‐Industrial Waste Compost and Vermicompost with or Without Earthworms

The aim of this study was to investigate the effectiveness of compost and vermicompost as soil conditioners in alleviating salt‐affected soils and increasing maize productivity. A greenhouse trial, consisting of seven soil amendment treatments in a completely randomized design with three replications, was carried out at Khon Kaen University, Thailand, during the rainy season of 2011. Plant height and total dry matter of maize increased in treatments with compost and vermicompost application when compared with the control (no fertilizer) in two types of soils (saline and nonsaline) during the growing season. Soil pH and electrical conductivity in saturation paste extracts were decreased by compost and vermicompost amendments with or without earthworms when compared with unamended treatments in the saline soil. Compost and vermicompost amendments improved cation exchange capacity, soil organic carbon, total nitrogen and extractable phosphorus in both soils. These amendments also increased exchangeable K⁺, Ca²⁺ and Mg²⁺ while decreasing exchangeable Na⁺ in the saline soil, which suggested that Ca²⁺ was exchanged for Na⁺, exchangeable Na⁺, then leached out, and soil salinity reduced as a result. Soil microbial activities including microbial C and N and basal soil respiration were improved by the application of compost and vermicompost amendments with or without earthworms when compared with the control in both soils. This experiment showed that the compost and vermicompost were effective in alleviating salinity and improving crop growth. Copyright © 2013 John Wiley & Sons, Ltd.     

Effect of Long-Term Sugarcane (Saccharum Spp.) Cultivation on Chemical and Physical Properties of Soils in Belize

The sugarcane industry in Belize is one of the main economic drivers in the country and is therefore of crucial social and environmental importance. This study evaluated the degree of sustainability of commercial sugarcane production in Northern Belize by determining soil parameters (physical and chemical) in three soil layers (0–15, 15–30 and 30–50 cm) and crop profitability relative to years of sugarcane cultivation (4–25 years since land conversion). The parameters evaluated were organic matter (OM), total nitrogen (TN), cation exchange capacity (CEC), available phosphorus (P), potassium (K), pH, dry bulk density (DBD), porosity (?), and water-filled pore space (WFPS). Field interviews were conducted to document management practices, agricultural inputs, production costs, and yield. The results showed that OM and TN in all soil layers studied and CEC in the 30–50 cm layer decreased, and were negatively correlated, with years of sugarcane cultivation. This indicates that prolonged sugarcane cropping has detrimental effects on soil fertility. There was no clear pattern with years under sugarcane cultivation for P, pH, DBD, and K. Yield levels were maintained by intensification of cultivation, e.g. high inputs and regular replanting, providing short-term benefits at the expense of deterioration of soil fertility. The benefit to cost (B:C) ratio of sugarcane production in Northern Belize was marginal for American Sugar Refinery/Belize Sugar Industries (ASR/BSI), representative of intensive agriculture; and not profitable for small-scale farmers, 1.0 and 0.63 for plantation establishment and 1.2 and 1.0 average for the following six years of ratoon, respectively.     

Treated Industrial Wastewater Effects on Chemical Constitution Maize Biomass,Physicochemical Soil Properties,and Economic Balance

Irrigation with treated wastewaters can improve nutrient levels and yield of crops planted on degraded soils. This study evaluated how irrigation with treated industrial wastewater affected biomass production and nutrition of maize plants and physio-chemical properties of a degraded soil. The experiment was conducted in a greenhouse using PVC columns. Treatments consisted of 8 treatments irrigated with clean water and increasing doses of N and P, and 8 treatments with 4 proportions of wastewater irrigation (25%, 50%, 75% and 100% v/v). In general, maize biomass did not differ between irrigation water sources. Differences were largely associated with N nutrition. We observed increases in concentrations of N, P, K, S, Mn, Na, Cu, and Zn in tissue of maize under irrigation with wastewater. The addition of treated wastewater increased the P and Na concentrations, and EC values in the soil without affecting clay dispersion in water. An associated economic analysis indicated that wastewater irrigation would not be economically feasible without including environmental benefits. In southern Brazil, the proportion of irrigation water that is wastewater should not exceed 50%.