Maize Height Research Articles

Movement of an insect parasitoid in simple and diverse plant assemblages

Abstract. 1. It has been proposed that herbivore populations are lower in diverse than in simple plant habitats because of greater abundance and/or higher efficiency of natural enemies in mixed plant stands. However, higher enemy colonization is expected in monorather than multispecific vegetation if the response of specialist natural enemies to habitat diversification is similar to that of monophagous herbivores.2. We used release‐recapture experiments to determine how the presence of maize (non‐host plant) influences the movement of the parasitoid Pediobius foveolatus in the absence of hosts. We then assessed how vegetation diversity affects wasp reproduction (parasitism) and subsequent density in the presence of its hosts, Mexican bean beetle larvae.3. Fewer female wasps immigrated into and more emigrated out of a bean‐tall maize intercrop than bean monocultures. Bean plant density and the presence of maize per se did not significantly affect parasitoid immigration. Instead, maize height was the primary factor contributing to lower female immigration into the bean‐tall maize plots. However, tall maize plants did not impede the wasps' within‐habitat movement.4. When wasps were released outside the plots, higher parasitism was recorded in monocultures, irrespective of host density. In contrast, when wasps were released within the plots, significantly higher parasitism rates were found in the bean‐tall maize habitat.5. Results suggest that female wasps accumulate in the bean‐tall maize habitat in response to resources other than hosts and, ultimately, wasp density may be determined primarily by differential emigration rather than by immigration rates.

Root and Shoot Growth Responses to Salinity in Maize and Soybean

AbstractSalinity generally reduces shoot growth of crops more than root growth, based on dry weight rather than length measurements. The objective of this study was to compare changes in root length to changes in shoot height under conditions of salinity, using the minirhizotron technique. The experiment was conducted in soil containers (55 cm long, 15 cm diam.), using greenhouse‐grown soybean [Glycine max (L.) Merr.] and field‐grown maize (Zea mays L.) as test crops. Segmented, nonlinear regression analysis showed changes in root length as viewed through minirhizotron tubes to be more sensitive to salinity than changes in shoot height, while there was no response to salinity treatment for final root dry weight. The regression coefficients of changes in relative shoot and root length vs. the electrical conductivity of the soil saturation extract (ECe) were 5.3 ± 4.0% per dS m−1 for soybean shoots and 6.6 ± 4.3% per dS m−1 for soybean roots. For maize, the values were 6.9 ± 1.6% per dS m−1 for shoots and 9.0 ± 4.9% per dS m−1 for roots. The regression coefficients of relative shoot height vs. relative root length of soybean and maize were 0.61 ± 0.27 and 0.66 ± 0.20, both significantly smaller than one. The discrepancy between the response in root length as measured by the minirhizotron technique and the response as measured in final root dry weights was attributed to the fact that changes in root length, as viewed in the minirhizotron video frames, depend more on new lateral root initiation than on extension of individual existing roots. Root extension is a turgor‐dependent process, as is shoot elongation, while lateral root initiation is not turgor dependent, and thus may be more sensitive to salinity. One might also speculate that the young, thin lateral roots are more sensitive to salt stress than the older, thicker main root system. Additionally, final root weight is insensitive to the addition of lateral roots if salinity treatments are initiated after the main root system is established, as was the case in this experiment.

The effects of organic and inorganic amendments on soil physical properties and maize production in a severely degraded sandy soil in southern Nigeria

The effects of different application rates of organic and inorganic fertilizers on soil physical properties and maize production in a severely degraded Ultisol in southern Nigeria were studied for two growing seasons. The addition of poultry manure (10 t ha −1) significantly decreased soil bulk density ( P = 0·05), increased soil organic matter content, total porosity, water infiltration into the soil and hydraulic conductivity. Water retention at low tensions of between 0·1 and 0·33 bar was significantly improved ( P = 0·05) and so, too, was the available-water capacity. There were high positive correlations between soil organic matter content and some measured parameters: total porosity ( r = 0·93), water retained at 0·33 bar tension ( r = 0·96) and available water capacity ( r = 0·96). Poultry-manure application significantly improved average maize height and average maize grain yield ( P = 0·05) in the two planting seasons. The soil organic matter content was highly correlated with yield ( r = 0·86). Poor response in terms of yield is a pointer to the important facts that severely degraded soils (‘badlands’) of southern Nigeria not only lend themselves to high wastage of added inorganic fertilizers, but also need sizeable quantities of organic amendments — exceeding 10 t ha −1 of poultry manure — for restoration of their productive capacities to optimum levels.

Physico-chemical properties and productivity of two tropical soils amended with dehydrated swine waste

With maize ( Zea mays L.) as the productivity indicator crop, the fertilizing value of dehydrated swine waste (DSW) was assessed on two texturally contrasting tropical soils, a sandy Kandic Paleustult (S l) and a clayey Lithic Usorthent (S 2). The treatments were different rates of DSW and inorganic fertilizer (F): 0%; 2·5%; 2·5% + F; 5·0%; 5·0% + F; 7·5%; 7·5% + F; 10·0%; 10·0% + F; and F alone. The F treatment consisted of the locally recommended rates of N, P, K and Mg for maize production. On both soils, high rates of DSW (⩾ 5·0%) delayed maize germination. Maize height and dry-matter yield increased with DSW rates, with the highest yield obtained at the 10·0% + F treatment. On all treatments, yield was consistently better on the more fertile S 2 than on the S 1 soil. All treatments including DSW out-performed the F-alone treatment because of higher nutrient contents of the organic waste-amended soils. The amounts of N, P, K, Ca and Mg released during the study explained individually between 66 and 73% of variation in maize yield on both soils. The C:N ratio of the treatments had an indirect effect on maize performance, explaining between 91 and 95% of the variation in yield. Increasing rates of DSW progressively increased the soil pH, organic carbon, N, P, exchangeable Ca, Mg, K and CEC, and reduced the exchangeable acidity at the end of the experiment. Also, the moisture retention capacity of both soils increased at all matric potentials between 0 and − 1500 kpa following DSW application. Even though the water-dispersible clay increased slightly with high DSW rates (implying reduced stability at the colloidal level), the overall effect of the organic amendment was towards enhanced resistance of the macro aggregates to disruptive water forces. Improvement in these physico-chemical properties was a direct consequence of increased organic matter levels following the DSW application to the soils.

Effect of Plant Population Densities on the Growth ofZea maysL. andArachis hypogaeaL. in Intercropping Systems

ABSTRACT A trial was conducted to evaluate the effect of plant population densities on the performance of short-duration genotypes of maize (Zea mays cv. TZESR-W-1) and groundnut (Arachis hypogaea cv. Valencia Mixed Red of Loudima) respectively in two simultaneous planting intercropping systems and as a monoculture. The six treatments were: sole maize; sole groundnut; sole maize fertilized with 100 kg N/ha; mixed crops of maize and groundnut at 1:4; 1:8 and 1:12 ratios respectively. Nodulation of groundnut, crude protein, cellulose and ear yield of maize were maximum in mixed crops at the 1:4 ratio. In contrast, intercropping maize and groundnut reduced dry matter and grain yields of both crops. The only exception was observed on nodule number and seed/pod yield ratio of groundnut, plant height, dry matter and grain yield of maize, where no differences were noted between monocropped and intercropped systems under farming conditions.

Use of poultry manure for amendment of oil-polluted soils in relation to growth of maize ( Zea mays L.)

The use of poultry manure for amelioration of oil-polluted soil was investigated by growing maize ( Zea mays L.) under two experimental conditions: increasing the poultry manure rate from 0–20 kg ha −1 at 0.03 L/kg oil treatment level; and increasing the rate of oil treatment from 0 – 0.2 L/kg, while the poultry manure amendment remained at 20 kg ha −1. A linear correlation existed between the rate of poultry manure added and the enhancement of maize growth (r = 0.99). But only a 16-kg ha −1 poultry manure rate and above exerted some beneficial effects on the maize growth relative to the unpolluted, unamended soil. Conversely, increasing oil concentration, regardless of the poultry manure level added (20 kg ha −1), depressed maize growth, but only at oil levels of 0.03 L/kg. A positive correlation was recorded between maize height and leaf area growing in oil-treated soil (0.03 L/kg) amended with different poultry manure rates (r = 0.99) and growing in oil-treated soils (0 – 0.2 L/kg) amended with 20 kg ha −1 poultry manure (r = 0.90). Amending oil-contaminated soils with poultry manure, should possibly improve soil fertility and maize production.

Changes of the displacement height and roughness length of maize during a growing season

Variations in the displacement height (d) and roughness length (z0) of a maize crop were investigated through a growing season. A programme of measurement from which the wind profile, the Richardson gradient number and the turbulent fluxes of heat and momentum were estimated, was carried out.Two techniques were combined to obtain unique values for d and z0: the log-profile fitting technique and the eddy correlation technique. Throughout the growing season, the displacement height appeared to correlate very well (r = 0.98) with the height (H) of the canopy. A mean value for d/H was 0.75. The roughness length was strongly correlated with the difference between the canopy height and the displacement height. A mean value of 0.26 for z0/(H − d) was found (r = 0.86). If the ratio d/H was fixed, the roughness length did not show any clear dependence on wind speed or thermal stability.

Effects of crude oil applications to soil on the growth and yield of maize, okro and cassava in Nigeria

The effects of different doses (0, 1, 2, 4 and 8 litres/m 2) of crude oil applications to soil on the growth and yield of maize, okro and cassava as well as on soil properties were investigated in two field experiments with mixed croppings (maize/okro and maize/cassava) in an acidic sandy loam soil at Port Harcourt, Nigeria. Crude oil applications above 2 litres/m 2 significantly affected crop germination, plant height and yield of maize and okro but not of cassava. Weed population in all the plots decreased significantly with increase in oil doses. Oil application slightly increased organic matter content, pHand total nitrogen content in the soils.

THE EFFECTS OF SOME METHODS OF ESTABLISHINGGLIRICIDIA SEPIUMON FOOD CROP PERFORMANCE, GROWTH AND SURVIVAL RATE OF GLIRICIDIA

SUMMARY Establishment of Gliricidia sepium with arable crops was studied in the Guinea Savanna zone of Nigeria using the alley cropping system. Maize height, grain yield and percent ear leaf nutrient content were not adversely affected by gliricidia during the establishment phase. Application of nitrogenous fertilizer significantly increased maize grain yield and gliricidia growth rate but not the survival rate of gliricidia. There were no significant effects on the yield of rice or yam. Survival of gliricidia declined with time in all the establishment methods used and was closely related to the occurrence of rainfall, especially in the case of 0.5m cuttings. The use of longer 1.2m cuttings gave significantly higher survival rates during the dry season and appeared to be the best method of establishment when rainfall is erratic. It is concluded that when intercropping gliricidia with food crops it is safe to plant both at the same time.

Nutrient contribution and maize performance in alley cropping systems

Dry matter yield and potential contribution of N, P and K of some woody perennials as well as performance of maize were assessed in an alley cropping system at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria. Dry matter yield was highest forCassia, followed byGliricidia and theFlemingia. Whereas dry matter yields ofCassia varied significantly at the various pruning times, those ofGliricidia andFlemingia were relatively uniform.Gliricidia contributed the highest amount of N from the cutback (first pruning) and three subsequent prunings. Dry wood yield at cutback was 14.5, 6.8 and 29.7 tonnes/ha forGliricidia, Flemingia andCassia respectively. Coppicing rate was faster inGliricidia thanFlemingia andCassia. Maize height, stover and cob weights were reduced though insignificantly, for the maize rows close to the shrub hedgerows compared to those in the middle of the alleys. For the plots without N application and prunings removed, the maize near the hedgerows showed better performance than those in the middle of the alleys. The results indicate that N supplementation is needed in the alley cropping systems to optimize yield. The amount of N required is higher inFlemingia alleys than forGliricidia andCassia. Root growth of maize was found to be restricted in control plots without hedges; uptake of the major nutrients (N, P and K) was also found to be similarly affected in those plots.

Nitrogen, phosphorus and potassium effects on the incidence of Striga asiatica (L.) Kuntze in maize

SummaryThis work was conducted in an attempt to elucidate some of the effects of nutrition on the incidence of witchweed (Striga asiatica (L.) Kuntze) in maize (Zeu mays L.).In an N, P, K field trial N applications resulted in up to 93% reduction in the incidence of witchweed. Maize height was unaffected by N and decreases in the incidence of Striga could not be attributed to the effects of host‐parasite competition. Although plant height was 10% lower on zero‐P plots, P did not have a significant effect on Striga and the beneficial effects of N were equally evident on both high and low‐P plots.Potassium applications had the opposite effect to N. While the main effect of K was not quite significant at the 5% level of probability, an N × K interaction was evident, and in the absence of applied N, K applications led to a more than 4‐fold increase in the incidence of Striga. As with N, K did not influence plant height and it seems unlikely that competition effects were responsible.

Field experiments to investigate long‐term effects of repeated applications of MCPA, tri‐allate, simazine and linuron: II. Crop performance and residues 1969–78

Summary:In four field experiments begun in 1963, each of four herbicides was applied to plots planted wilh the same crop each year. The annual treatments were: MCPA at 17 kg/ha to barley (Hordeum sativa Jess) and wheat (Triticum aestivum L.) at growth stage 15. tri‐allate at 17 kg/ha pre‐emergcnce to barley and wheat, simazine at l7kg/ha pre‐emergence to maize (Zea mays L.) and linuron in two applications of 084 kg/ha pre‐ and post‐emergence to carrots (Daucus carota L.).MCPA did not affect growth or yield of either barley or wheat. In general tri‐allate also did not aftect the crops although wheat yield was depressed in 1978, wheat 1000 grain weight was reduced in 1972 and barley germination percentage was increased in 1973. Simazine did not influence the height, yield or appearance of maize. Linuron normally produced no effect on carrot yield, density and size. However, in 2 years when the post‐emergence application was late, density but not yield was lower than in control plots. There was no accumulation of residues of any of these compounds in the soil. Rates of loss were similar to those predicted on ihe basis of laboratory experiments.In a fifth experiment these herbicides were applied twice per year (3 times in the case of linuron) at double the rales above on each occasion to bare plots. These applications ceased in 1968 (1969 for MCPA) but residues were monitored until 1972 except in the case of MCPA. Disappearance rates were similar to those in the cropped plots and residues were largely confined to the top 10 cm. The plots treated with MCPA had developed an enhanced ability lo degrade il prior to 1968. This persisted for 5 years after the final application.

Effects of Arbuscular Mycorrhiza in the Productivity of Maize and Fingermillet Relay Cropping System

Field experiments were conducted in farmer field in 2008 to scrutinize the effects of AM fungi in the productivity of maize/fingermillet cropping system in the rainfed dryland area of Kavrepalanchwok district. Following randomized complete block design, six treatments with four replications were maintained. Results showed significant effect of AM inoculation on plant height and yield of maize at 1% level of significance, whereas fingermillet was positive with nonsignificant difference on both parameters. Improvement in available soil phosphorus status was observed distinct in both maize (26.51±9.54 kg P2O5/ha) and fingermillet (30.11±15.15 kg P2O5/ha) in arbuscular mycorrhiza treated plots (T3) than control (T1). Arbuscular mycorrhiza spore density was also improved in the mycorrhiza treatments with (T6) and without nitrogen and potash fertiliser (T3) as compared to control (T1) in both maize and fingermillet.Key words: Biofertiliser; Endomycorrhiza; Grain yield; Soil productivityDOI: 10.3126/njst.v10i0.2823Nepal Journal of Science and Technology Volume 10, 2009 December Page: 51-55

Effect of Thinning on Stand, Yield, and Plant Height in Maize1

We conducted experiments at two locations for 4 years to determine the effect of thinning on stand, yield, and plant and ear height of maize (Zea mays L.). We included a control (no thinning) and over‐planting and thinning at three stages of plant development (2 to 3, 5 to 8, and 9 to 11 leaf‐stages) in all experiments. Average stand improvement was 8% over the control regardless of the stage of thinning. Thinning at the 5 to 8 and 9 to 11 leaf‐stages resulted in significantly lower yields than thinning at the ''. to 3 leaf stage. Yields of the control plots were not significantly different from the yields obtained on the plots thinned at the 5 o 8 leaf‐stage, the latter having 8% higher stands. Plant and ear height also decreased with the later stages of thinning. The experiments showed that over‐planting and thinning was justified for improving stands, but that thinning at different sages did affect yield of grain significantly.