Factorial Treatment Combinations Research Articles

Plant density and variety effect on yield, leaf spot disease, weed species richness and diversity of groundnut production in northern Ghana

AbstractLow plant density and weed infestation are major challenges for groundnut production in northern Ghana. A two‐year on‐farm study was conducted to determine the effect of plant density and variety on grain and fodder yields, incidence of leaf spot disease, weed species diversity and biomass. A factorial treatment combination of 6 varieties and 4 plant densities laid in strip plot design with 4 replications was used. The varieties were (early maturity type: Chinese, Yenyewoso, Samnut 23 and late maturity type: Azivivi, Manipinta, Samnut 22). The plants density included 9, 11, 15 and 22 plants/m2. The late maturity varieties recorded higher (p < .05) canopy cover, grain and fodder yields relative to that of the early maturity varieties. The late maturity varieties also recorded the least sedge weed species frequency, density and incidence of leaf spot disease compared with that of the early maturity varieties. The canopy cover, grain and fodder yields increased with increasing plant density. Broadleaf weed species frequency and density, weed biomass, richness, and diversity declined with increasing plant density. Grain yield showed negative and significant correlation with broadleaf weed species frequency, density and weed biomass. The results suggest that both early and late maturity groundnut varieties can be planted at a density of 22 plants/m2 to increase grain and fodder yields and reduce weed species richness, diversity and growth in northern Ghana and similar agro‐ecology in West Africa.

Management of Covered Kernel Smut (Sporisorium sorghi) Disease of Sorghum (Sorghum bicolor) at Gabilley District in Somaliland

Sorghum is multi-purpose crop that plays an important role in the socio-economic life of farming communities in Somaliland. However its production and productivity is threatened due to Covered kernel smut disease. A field experiment was carried out at Aburin Agricultural Research Center at Gabilay district in Somaliland in order to identify management options for Covered kernel smut disease of sorghum. The experiment consisted of 12 factorial treatment combinations of three varieties (i.e., Faruryogele, Abadro and Kuso) and three types of seed treatments which includes synthetic and bio-fungicides (i.e., Apron star 42WS%, Cow urine, and Neem seed kernel extract) and including Untreated control, laid out in RCBD with three replications. Parameters such as disease incidence, disease severity, phenological data, grain yield (kg)/plot, actual grain yield/plot, 1000 grains weight (g) and yield loss (%) were collected. The experiment result showed that highest disease (44.0%) incidence was recorded on untreated Kuso variety while lowest disease (4.33%) incidence was Apron star with Abadiro. Similarly, the highest disease severity (37%) was scored from Untreated Abadiro whereas lowest disease severity (4%) was scored from Abadiro with Apron star and Faruryogele with Apron star. Untreated Abadiro variety reached highest AUDPC (1036.0% days). The Apron star treated varieties had the lowest AUDPC and consistently showing markedly low infection rates indicating that they were more effective to the disease relative to the other seed treatments. The highest yield (1896 kg ha-1) was recorded from Faruryogele with Apron star and lowest (933 kg ha-1) was recorded from untreated Abadiro and Faruryogele. So, Apron star was effective to reduce the yield loss of sorghum and could be recommended to manage sorghum covered kernel smut. However, the experiment should be repeated across different environments over years in order to give the right recommendations and its rate may need to be well defined.

Effect of postharvest application of plant powders on physical quality and shelf life of okra during storage in Makurdi

The effect of postharvest application of plant leaf powders on the physical quality and shelf life of okra fruits during Storage in Makurdi was determined. Moringa and Neem leaf powders were used to coat the okra fruits, which were then kept at room temperature. The experiment was a 2 x 3 factorial combination of treatments, fitted in a completely randomized design, and replicated thrice. Data collected were subjected to Analysis of variance (ANOVA) using GENSTAT statistical package, and Fisher’s Least Significant Difference (F-LSD) at a 5% level of probability to separate the means. Results revealed that plant leaf powders of Azadirachta indica (Neem) and Moringa oleifera have the ability to enhance the shelf life and maintain the physicochemical quality of okra fruits under storage. These powders also have the potential to be antifungal. Among the okra varieties studied, Clemson spineless gave better physical quality as compared to stubby okra thus the shelf life during storage. Treated okra shelf life extended to day 15 whereas the untreated fruits ranged from 1 - 7 days. These botanicals offer alternatives for maintaining crop management and postharvest physiology in addition to being safe for consumers, inexpensive, easy to create, and easy to apply formulations. It is therefore recommended the use of plant leaf powders particularly M. oleifera for the storage of okra fruits in Makurdi.

Experimental disturbance and productivity gradients drive community diversity in aquatic mesocosms.

Combined effects of disturbance and productivity on ecological diversity have been considered for decades as the dynamic equilibrium model (DEM) but are rarely tested together. Instead, most studies focus on either the intermediate disturbance hypothesis or sometimes the intermediate productivity hypothesis. In addition, most analyses of disturbance and productivity effects have relied on nonexperimental patterns, limited sample sizes, inaccurate proxies for productivity, and/or simple measures of diversity. The DEM operates at regional and local scales; here, we conducted a year-long experiment at local scales using submersed aquatic vegetation in outdoor mesocosms with a factorial combination of physical disturbance and productivity treatments. We evaluated diversity in several ways, directly measured productivity, and compared alternative hypotheses using model selection. The DEM was supported for effective diversity; both productivity and disturbance effects were clear, though productivity effects were stronger. Other diversity measures for the simple communities in the mesocosms did not clearly reflect treatments. The DEM is a valuable general framework for understanding disturbance and productivity effects on ecological systems and is made more general by minor conceptual adjustments here.

Dry rainfed conditions are key drivers of the effect of conservation tillage and a nitrification inhibitor on N fate and N2O emissions: A field 15N tracing study

The sustainability of rainfed crops under semiarid conditions is threatened by low plant nitrogen (N) recovery as well as the potential loss of reactive N to the environment. A field 15N tracing experiment on barley (Hordeum vulgare L.) under rainfed conditions was carried out to study how different tillage management practices and the use of the nitrification inhibitor DMPSA affected the fate of N. The experiment consisted of a factorial combination of tillage (i.e., no tillage, NT, and conventional tillage, T) and fertilizer treatments (unfertilized control and ammonium nitrate, AN, with or without DMPSA). Single-labelled ammonium nitrate (15NH4NO3, 15AN, or NH415NO3, A15N) was applied at top-dressing to microplots at a rate of 80 kg N ha−1. Our results show out that DMPSA modulates the nitrification process from both fertilizer-N and endogenous soil-N (which was the main contributor to plant N uptake and N2O emissions), affecting soil residual N at the end of the cropping period (i.e., higher topsoil retention of 15AN in DMPSA-amended plots). Generally, cumulative N2O emissions from fertilizer were derived from 15AN rather than from A15N, thus confirming the site-specific choice of the source of synthetic N as an effective N2O mitigation strategy. Two months after harvest, a rewetting event produced a remarkable N2O emission peak that drove total cumulative N2O emissions and was also mainly derived from endogenous N. These results suggest that dry seasons could decrease N2O losses after fertilization while causing critical peaks after rewetting, thus potentially limiting the effectiveness of mitigation strategies. The average plant N recovery from the synthetic fertilizer was 22.6%, while the use of DMPSA combined with NT enhanced plant N uptake from endogenous soil-N. This could be a result of the improved crop development and plant N acquisition under NT, consistent with the decrease of soil N retention for A15N in the deeper layer at the end of the experiment in the nontilled plots. This study contributes to the mechanistic understanding of the effect of nitrification inhibitors and tillage on N2O emissions, soil N dynamics and N plant recovery, revealing relevant effects of both management strategies and a critical role of endogenous soil-N under dry rainfed conditions. It can be concluded that, under the conditions of our study, combining DMPSA with NT could help to improve plant N recovery, thus resulting in positive impacts on reactive N loss and climate change mitigation and adaptation.

Effect of Cassava-Legume Intercropping Systems on the Population Dynamics of Legumes Insect Pests in Three Major Agro-Climatic Zones of Sierra Leone

Field trials were conducted in three agro-climatic zones of the country to evaluate the effect of cassava-legume-based intercropping systems on the population dynamics of legumes insect pests. The experiment consisted of a factorial treatment combination of seven cropping systems, two cassava architectures, and two spatial arrangements. The study reveals that a higher percentage incidence and severity scores of the legumes insect pests were recorded on the sole legumes compared to the intercropping systems. Also, intercropping the grain legumes using the erect cassava variety at a spatial arrangement of 1 m x 1 m recorded the lowest number of pests per plant, incidence and severity of legumes insect pests compared to the branched cassava architecture, and the 2 m x 0.5 m spatial arrangement. In conclusion, it was shown that, cassava-legume intercropping systems could significantly influence reduction in the number of pests per plant, incidence, and severity of legumes insect pests.

Cowpea Living Mulch Effect on Soil Quality and Grain Yield in Smallholder Maize-Based Cropping System of Northern Ghana

Low soil fertility is a major constraint for maize production in West Africa, the use of legumes as living mulch improves soil fertility and yield of main crops. However, there is limited literature on the appropriate time to plant living mulch in maize-based cropping system in West Africa. A 2-year (2017–2018) study was conducted to determine the effect of cowpea living mulch (CPLM) on soil quality and grain yield in maize-based cropping system of northern Ghana. A factorial treatment combination of three maize maturity types (extra-early, early and medium) and four CPLM methods (control, CPLM with maize planted on the same day, CPLM planted 1 week after maize and CPLM planted 2 weeks after maize) was laid out in a randomized complete block design with four replications in Northern and Upper East regions of Ghana. Principal component and correlation matrix analyses were used to select minimum data set for soil quality index (SQI) calculation. The SQI for CPLM improved by 50–100% relative to that of the control in both seasons and regions. The CPLM significantly increased maize grain by 34–37% during both seasons in Northern Region and 84% during 2017 in the Upper East Region compared with that of the control. The effect of time of planting CPLM on grain yield showed negative correlation with amount of rainfall received during vegetative growth of CPLM. The results suggest that smallholder maize-based farmers in northern Ghana and similar agro-ecologies in West Africa can plant CPLM 1–2 weeks after planting maize to improve soil quality and increase maize grain yield.

Evaluation of Elites Isolates of Bradyrhizobia Nodulating on Groundnut Varieties (Arachis hypogaea L.) at Assosa District of Western Ethiopia

A field experiment was conducted on Nitisols of Asossa Agricultural Research Centre during 2017/18 2018/19 cropping season to investigate the response of yield, partial budget analysis of ground nut varieties to bio-fertilizer and inorganic nitrogen. Two locally suitable varieties 4 groundnut rhizobial strains with control and 18 kg N ha-1, totally 12 treatments had combined in factorial RCBD. TSP fertilizer was applied uniformly to all plots at 46 kg P2O5 ha-1. The treatments consists of: two Varieties of groundnut (V1= Muniputer V2= Babile 2) and 4-strains with 18 kg N ha-1 and uninoculated (control) factorial treatment combination were tested. Analysis of variance for two factors randomized complete block design (Table 1) revealed highly significant difference (P < 0.001) due to the main effects of rhizobia and verities for the means of seed yield. On the other hand the interaction effects of rhizobia and varieties had non-significant (p>0.05) for the means of seed yield, nodule dry weight and straw dry weight. The highest (186.5) nodules per plants were recorded from the interaction effect of Dibate moderate and Maniputer variety, while less nodules per plant (76.25) were produced by Dibate moderate with Babile variety. The Dibate 2 rhizobia had the highest net-benefit of 67,655 Ethiopian birr. The lowest net benefit was obtained by the application of the Dibate moderate and none inoculant. The profitability of the study showed that application of Moderate 2 rhizobia which provided the relatively high net benefit (67,655 ETB), was recommended to apply bio fertilizers. The % MRR between any pair of undominated treatments denotes the return per unit of investment in fertilizer expressed as a percentage. Economic analysis revealed that maximum marginal rate of return was recorded with application of Dibate 2 (9257.2%). So we could be recommended Dibate 2 strain for ground nut production in Asossa district. The best recommendation for treatments is not necessarily based on the highest marginal rate of return, rather based on the minimum acceptable marginal rate of return and the treatment with the high net benefit, relatively low variable cost together with an acceptable MRR becomes the tentative recommendation.

Impacts of drought intensity and weed competition on drought-tolerant corn performance

AbstractWater stress and weed competition are critical stressors during corn (Zea mays L.) development. Genetic improvements in corn have resulted in hybrids with greater tolerance to abiotic and biotic stressors; however, drought stress remains problematic. Therefore, in light of the anticipated change in precipitation throughout the Great Lakes Region, greenhouse experiments were conducted to evaluate water stress and weed competition on drought-tolerant corn performance. The study followed a completely randomized block design with four replications. Factorial treatment combinations consisted of drought-tolerant corn competition (presence or absence), water stress (100% or 50% volumetric water content [VWC]), and nine corn:common lambsquarters (Chenopodium album L., CHEAL) densities. Corn and C. album growth parameters were measured at 14 and 21 d after water-stress initiation. To explore the impact of reduced soil moisture and weed competition on corn and C. album growth parameters, photosynthetic response, and biomass, linear mixed-effects and nonlinear regression models were constructed in R. Chenopodium album biomass was reduced by 46% and 50% under corn competition at 2 and 4 weeds pot−1 (P = 0.0003, 0.0004). However, introducing crop competition under 6 and 9 weeds pot−1 did not reduce C. album biomass (P = 0.90, 1.00). Averaged across weed pressures, corn biomass was 22% less when grown under 50% compared with 100% VWC (P = 0.0003). However, averaged across VWC values, increasing weed competition from 0 to 2 (P = 0.04), 4 (P = <0.0001), 6 (P = 0.0002), or 9 (P = 0.0002) weeds pot−1 reduced biomass by 22%, 38%, 35%, and 36%. Overall, water stress and C. album competition negatively affected the parameters measured in this study; however, the magnitude of reduction is stronger under drought stress than increasing weed competition when water is not limiting. Therefore, field crop growers must modify current integrated weed management programs to maintain yield under future climate stress.

Influence of farm yard manure and N-levels on the growth, yield characters and yield of sesame (Sesamum indicum L.)

Field experiment was conducted at the Kogi State University Research and Demonstration Farm Anyigba, (Lat 7° 291 and Long 70 111E). Anyigba lies in the Guinea Savanna Agro-ecological Zone. This experiment was conducted during the raining season of 2021 to evaluate the effect of Farm Yard Manure and Nitrogen levels on the growth, yield characters and seed yield of sesame (Sesamum indicum L.). Treatments consisted of three levels of Farm Yard Manure (0 t ha-1, 5 t ha-1, 10 tonsha-1and 15 t ha-1) respectively and Nitrogen fertilizer rates (0 tons Nha-1, 0.02 t N ha-1, 0.04 t N ha-1and 0.06 t N ha-1) respectively. Factorial combination of treatments gave a total number of 16 treatments which was laid in a Randomized Complete Block Design (RCBD) with three replicates. 48 plots were obtained in total. Results showed that application of Farm Yard Manure did not influence (p≥0.05) all parameters studied in the experiment except dry weight/plant, plant height and seed yield/ha. Nitrogen application significantly influenced (p≤0.05) plant height and seed yield only. There was no significant interaction observed between Farm Yard Manure and Nitrogen levels in all parameters studied.

Effect of plant growth regulators and fertigation on nutrients uptake and soil fertility of pomegranate (Punica granatum L.) in vertisols of South-East Rajasthan

In this study, the experiment was laid out in Factorial Randomized Block Design and treatment combinations consisting of plant growth regulators levels (Naphthalene acetic acid 0, 50 and 100 ppm and ethrel 0, 150 and 250 ppm) and fertigation levels (0, 75 and 100% recommended dose of fertilizers). Maximum mean electric conductivity (0.356 dS/m), soil nitrogen (298.30 kg/ha), soil phosphorus (49.29 kg/ha), soil potassium (417.47 kg/ha), soil organic carbon (0.370%) and water holding capacity (46.17%) was noticed under 100 per cent recommended dose of fertilizers through fertigation. However, interaction effects were found to be better to their individual effects and showed that interaction of 100 ppm NAA + 150 ppm ethrel + 100 per cent RDF through fertigation (N2E1F2) significantly improve the physico-chemical properties of soil. Similarly, among the different interaction effects, maximum mean leaf nitrogen (2.086%, 2.163% and 1.901%), leaf phosphorus (0.203%, 0.246% and 0.186%) and leaf potassium (1.857%, 1.969% and 1.654%) was recorded in treatment N2E1F2 at 60, 120 and 180 days after treatment, respectively. Our results suggest that spray of plant growth regulators at pre flowering and post flowering stage and application of fertigation in four equal split dose from 1 July to 1 October was a better measure to improve physico-chemical properties of soil as well as nutrient content of plant. Our research provides scientific basis for the technology in interaction of soil and plant nutrients.

Optimizing Food and Feed in Maize–Livestock Systems in Northern Ghana: The Effect of Maize Leaf Stripping on Grain Yield and Leaf Fodder Quality

Access to feed for livestock during the cropping season is a constraint to the smallholder crop–livestock farming system in northern Ghana due to backyard farming. A two-year (2017–2018) study was conducted to determine the effect of leaf stripping on yield and feed quality in maize–livestock farming systems in the Northern, Upper East, and Upper West regions of Ghana. A factorial treatment combination of three maize-maturity types (extra-early: Abontem, early: Omankwa, and medium: Obatanpa) and three leaf stripping methods (control, leaf stripping at 50% tasseling, and leaf stripping at 50% silking of maize) were laid out in a strip-plot design with four replications per region. Stripped leaf biomass, grain yield, stover, cob size, and nutritional quality of stripped maize leaf were measured. The stripped leaf biomass, stover, and cob width of Obatanpa increased significantly relative to the other maize types in the Northern and the Upper West regions. Abontem recorded a higher (p < 0.01) grain yield than that of the other maize types in the Upper East Region. Leaf stripping had no significant effect on the grain yield and the crude protein (CP) content of maize leaf. The CP of the maize leaf (93–100 g/kg) was above the minimum CP requirement of a quality feed for body weight maintenance of ruminants. This suggests that smallholder maize–livestock farmers could strip maize leaves at either tasseling or silking to feed their livestock during the cropping season in northern Ghana and similar agro-ecological zones in West Africa.

Effects of Pruning and Nitrogen Fertilization for The Rejuvenation and Physicochemical Characteristics Of Fruits of Declining Apricot Trees (Prunus Armeniaca L. CV. New Castle)

Effects of pruning and nitrogen fertilization for the rejuvenation and physicochemical quality of fruits, bearing on declining apricot trees (Prunus armeniaca L. cv. New Castle) were assessed. Studies were conducted from 2011 to 2015 on the 25 years old senile and declining apricot trees. Ten treatments comprised of a factorial combination of three pruning levels/severity (heading back of main scaffolds at 20, 40 and 60%) with three levels of nitrogen doses (500, 625 and 750g N/tree). For the first time in the year 2011, the experimental trees received the treatments during its dormant period (winter). In the successive years, all the treatments were followed by corrective pruning facilitate rapid restoration of growth and production of the orchard. The factorial treatment combination of heavy pruning (60%) with the lowest doses of nitrogen level (500g/tree) increased the qualities of fruits in terms of weight, volume, firmness, total soluble solids, sugars and acidity content. Whereas, the ascorbic acid content was facilitated by heavy pruning (60%) with the highest doses of nitrogen level (750g/tree) in all the following years. Bangladesh J. Bot. 50(4): 1119-1126, 2021 (December)

Effects of forest canopy gaps on the ground‐layer plant community depend on deer: Evidence from a controlled experiment

AbstractQuestions: How do deer mediate the response of forest ground‐layer plant communities to canopy gap size?Location: Flambeau River State Forest in north central Wisconsin, USA (47°37.4ʹ N, 90°47.8ʹ W).Method: We examined responses of resources, growth forms and temporal guilds to factorial combinations of canopy gap treatments consisting of a range of gap sizes (80, 200 and 380 m2), and deer (Odocoileus virginianus) exclusion (0.64 ha fenced exclosures) 4 years following gap creation (3 years following deer exclusion). We contrasted responses in central and transition zones.Results: In the absence of deer, forb productivity increased from pre‐treatment levels, particularly where light transmittance and soil moisture were high. In contrast, forb productivity decreased in the presence of deer. These effects were stronger among forbs with early‐ and late‐summer leafing phenology than spring ephemeral, and evergreen species. In contrast, deer amplified increases in graminoid productivity, which were related primarily to light transmittance. Deer did not alter responses of ferns, shrubs, trees seedlings or vines. Canopy gaps increased community heterogeneity among gap sizes and zones, but only in the absence of deer. This was related to the effects of deer on the composition and diversity of gap specialists.Conclusions: The maintenance of biodiversity in northern temperate forest ground‐layer plant communities by canopy gap dynamics appears to hinge on deer herbivory, even at relatively modest populations of deer and a productive site. Conversely, increases in resource availability within gaps may function to mitigate some negative effects of deer on forb productivity. Effects may be transient, as species turnover to shrub‐ and sapling‐dominated communities and canopy closure may cause communities to converge in the future. However, populations of undefended gap specialists remain particularly sensitive.

Characterising the effect of crop species and fertilisation treatment on root fungal communities

Information about the root mycobiome may improve the overall quality of the plants and contribute to a valuable strategy to enhance sustainable agriculture. Therefore, we assessed differences in fungal community diversity and composition in the roots of potato, wheat and barley grown under mineral nitrogen fertilisation at five rates, with and without farmyard manure amendment. The same factorial combination of treatments has been used since 1989. Species richness and diversity, as well as community composition, of different fungal guilds were characterised using Illumina MiSeq sequencing of the ITS2 region. Crop species was the main factor determining overall fungal richness and diversity, with wheat showing the highest, and potato the lowest, richness and diversity. Pathogen diversity indices were highest in wheat plots amended with farmyard manure, whereas the lowest values were observed for potato roots. Fertilisation treatments and the interaction between crop species and fertilisation had the strongest impact on arbuscular mycorrhiza and saprotroph diversity. Crop species also determined the composition of the overall fungal community and that of fungal guilds, whereas fertilisation treatment had only a minor effect. This study highlights crop species as the main driver in shaping root fungal diversity and composition under the same environmental conditions.

Increased light availability due to forestry mowing of invasive European buckthorn promotes its regeneration

The invasive shrub Rhamnus cathartica L. (common buckthorn) dominates the understory of many temperate forests of eastern North America. Common buckthorn outcompetes native understory species for light, forming monospecific stands that suppress plant and animal diversity. Removing common buckthorn is a common management priority within its invasive range. In recent years, forestry mowing has become popular in removing common buckthorn. This control method removes a midstory of common buckthorn, increasing light availability to the lower understory (which could favor buckthorn regeneration) and creating a layer of mulch on the forest floor (which could suppress buckthorn regeneration). Here we investigate whether and how increased light availability and increased ground cover (mulch) resulting from forestry mowing affects buckthorn regeneration from the seed bank. We evaluated buckthorn germination, survival, and early growth in response to a factorial combination of shading treatments and buckthorn mulch depth treatments in an oak forest in Minnesota, U.S.A. Increased light availability increased buckthorn seedling survival and growth, whereas increased mulch depth did not significantly affect the number of buckthorn establishing from seed over one growing season and winter. Thus, removing buckthorn by forestry mowing (or any other method) is likely to facilitate buckthorn reestablishment by increasing light availability at the ground.

Sensitivity of weedy rice populations to Quizalofop

Abstract Background: Rice lines displaying resistance to quizalofop-p-ethyl (quizalofop), an acetyl coenzyme A carboxylase (ACCase)-inhibiting herbicide, were developed to facilitate control of imidazolinone-resistant weedy rice (red rice), as well as other susceptible grasses. Objective: To assess the sensitivity of weedy rice accessions from Brazil to quizalofop. Methods: Two bioassays were conducted on the greenhouse from March to June 2016, in a completely random design with a two-factor factorial combination of treatments and four replications. The factor A was weedy rice accession and factor B was quizalofop rates (0, 25 and 50 g a.i. ha-1). It was assessed a total of 84 genotypes in the two bioassays, composed of 78 weedy rice accessions, 4 rice cultivars, and 2 lines resistant to aryloxyphenoxypropionate (AOPP) herbicides. Quizalofop was applied the 2-leaf stage. Weedy rice control was evaluated at 28 and 22 days after treatment (DAT), respectively for bioassay I and II, using a scale of 0% (no control) to 100% (dead). Results: All weedy rice accessions were susceptible to quizalofop, being controlled 100% with 50 g a.i. ha-1. Rice lines SC 964 and SC 965, resistant to AOPP herbicides, were not injured by quizalofop. Conclusions: quizalofop is an effective tool for weedy rice control in ACCase-resistant rice.

Fodder Production and Livestock Rearing in Relation to Climate Change and Possible Adaptation Measures in Manaslu Conservation Area, Nepal

A study was conducted to find out the production potential, nutrient composition, and the variability of the most commonly available fodder trees along with the varying altitude to help optimize the dry matter requirement during winter lean period. The study was carried out in Lho and Prok Village Development Committee of Manaslu Conservation Area (MCA), located in Gorkha district of Nepal.The study was conducted in two parts: social and biological. Accordingly, a households (HHs) survey was conducted to collect primary data from 70 HHs, focusing to the perception of respondents on impacts of climatic variability to the feeding management. The next part consisted of understanding yield potential and nutrient composition of the four most commonly available fodder trees (M. azedirach, M. alba, F. roxburghii, F. nemoralis), within two altitudes range: (1500-2000 masl and 2000-2500 masl) by using a RCB design in 2*4 factorial combination of treatments, each replicated four times. Fresh yield and dry matter yield of the each fodder trees was significant (P<0.01) between the altitude and within species. Fodder trees yield analysis revealed that the highest dry matter (DM) yield (28 kg/tree) was obtained for F. roxburghii but that remained statistically similar (P>0.05) to the other treatment. On the other hand, most of the parameters: ether extract (EE), acid detergent lignin (ADL), acid detergent fibre (ADF), cell wall digestibility (CWD), relative digestibility (RD), digestible nutrient (TDN), and Calcium (Ca) among the treatments were highly significant (P<0.01).
 Int. J. Appl. Sci. Biotechnol. Vol 7(2): 227-235

Crop rotation and tillage affect nematode communities more than biocides in monoculture soybean

Long-term monoculture of susceptible soybeans naturally develops suppressiveness to soybean cyst nematode (SCN) Heterodera glycines if fields are not tilled or biocides applied. Nematode community indices, that integrate the responses of different taxa and trophic groups to perturbation, provide a tool to monitor the ecological status of soil communities. We tested the hypothesis that soil suppressiveness to Heterodera glycines is correlated positively to management practices that favor both greater trophic diversity (food web complexity) and a later stage ecological succession (less disturbance) within free-living nematode communities. A factorial combination of cultivation, crop rotation, and biocide application treatments were monitored for four years in a field with a history of no-till and monoculture of susceptible soybean for 15 years. Crop rotation had the greatest impact on nematode community index values followed by descending order of cultivation and biocides. Suppressive soils did have greater food web complexity, but not necessarily ecological succession. Nematode community composition was influenced by covariables nitrogen and organic matter content (mean 6.6%), but not pH or salinity. The study is novel by using a food web approach that includes multiple trophic levels rather than simply population ecology.

Analysis of variance in soil research: let the analysis fit the design

SummarySound design for experiments on soil is based on two fundamental principles: replication and randomization. Replication enables investigators to detect and measure contrasts between treatments against the backdrop of natural variation. Random allocation of experimental treatments to units enables effects to be estimated without bias and hypotheses to be tested. For inferential tests of effects to be valid an analysis of variance (anova) of the experimental data must match exactly the experimental design. Completely randomized designs are usually inefficient. Blocking will usually increase precision, and its role must be recognized as a unique entry in an anova table. Factorial designs enable questions on two or more factors and their interactions to be answered simultaneously, and split‐plot designs may enable investigators to combine factors that require disparate amounts of land for each treatment. Each such design has its unique correct anova; no other anova will do. One outcome of an anova is a test of significance. If it turns out to be positive then the investigator may examine the contrasts between treatments to discover which themselves are significant. Those contrasts should have been ones in which the investigator was interested at the outset and which the experiment was designed to test. Post‐hoc testing of all possible contrasts is deprecated as unsound, although the procedures may guide an investigator to further experimentation. Examples of the designs with simulated data and programs in GenStat and R for the analyses of variance are provided as File S1.Highlights Replication and randomization are essential for sound experimentation on variable soil. Analyses of variance of data from experiments must match the experimental designs. Experiments should be designed to answer preplanned questions and test hypotheses. Efficiency can be gained by blocking and factorial combinations of treatments.