DETERMINATION OF VARIABILITY IN SOIL PHYSICAL PROPERTIES AND MICROBIAL BIOMASS UNDER CONTINUOUS DIRECT-PLANTED CORN

1986 ◽  
Vol 66 (4) ◽  
pp. 747-750 ◽  
Author(s):  
M. R. CARTER ◽  
R. P. WHITE

The spatial variability of soil strength, porosity, and microbial biomass was determined under 4-yr continuous direct-planted silage corn (Zea mays L.) on Prince Edward Island. All soil properties changed relative to the row position. Microbial biomass C and N were lower in the in-row compared to the between-row position. Positional and depth differences for soil bulk density and volume of macropores (EPD > 50 μm) were only evident at the soil surface (0–8 cm). Temporal and spatial variations in soil strength indicated the extent of the rooting potential within the soil profile, the depth to compacted soil layers, and the degree of soil structure regeneration during the winter period. Key words: Spatial variability, soil strength, soil porosity, microbial biomass, direct-planted corn, Zea mays L.

1983 ◽  
Vol 63 (1) ◽  
pp. 235-241 ◽  
Author(s):  
J. A. IVANY ◽  
J. R. ENMAN

Forage corn (Zea mays L.) was grown successfully in Prince Edward Island by no-till planting the corn into standing cereal stubble 15–20 cm tall using a Buffalo no-till seeder. Planting with the slot-type shoe in a preliminary experiment in 1978 gave better forage yields than planting with a slice-type shoe mainly because of better plant population achieved. Subsequent experiments in 1979–1981 using the slot-type shoe to no-till plant corn in cereal stubble gave good forage yields when adequate weed control was provided with herbicide treatment. Best control of quackgrass (Agropyron repens L. Beauv.) and dandelion (Taraxacum officinale Weber) and crop yields was achieved with glyphosate + atrazine (1.5 + 2.5 kg a.i./ha) or amitrole + atrazine (3.4 + 2.5 kg a.i./ha) applied preemergence after seeding corn and before corn emergence. Control of quack grass and dandelion with glyphosate or amitrole used alone ranged from 71–80%, but paraquat alone did not provide any weed control. Addition of atrazine to paraquat, glyphosate, or amitrole gave improved control of quackgrass and dandelion and higher forage corn yields. Addition of 2.5 kg a.i./ha atrazine gave better results than use of 1.0 kg a.i./ha of atrazine.Key words: Forage corn, no-till seeding, glyphosate, atrazine, aminotriazole, paraquat


1987 ◽  
Vol 67 (3) ◽  
pp. 445-456 ◽  
Author(s):  
M. J. SHIPITALO ◽  
R. PROTZ

Effects of tillage on soil morphology and porosity were investigated in plots planted to corn (Zea mays L.) for seven consecutive years. Micromorphometric analyses indicated that Ap horizons of no-till plots had approximately half the macroporosity (pores ≥ 200 μm equivalent circular diameter) of those of conventionally tilled plots. Loss of macroporosity was characterized by a decrease in mean pore size and a tendency for pores to become elongated, less tortuous, and oriented parallel to the soil surface. Obvious zoological activity, which consisted mainly of burrowing earthworms, resulted in two to nine times more bioporosity in a no-till pedon than in a conventionally tilled pedon. Earthworm activity also contributed to the formation of 5-cm-thick B & A horizon and a more uniform distribution of organic carbon than in the conventionally tilled pedon. These differences in morphology are reflected in the classification under Soil Taxonomy but not under the Canadian System. We speculate that zoological activity may serve to counteract the reduction in macroporosity in the Ap of the no-till pedon. Key words: Bioporosity, earthworms, micromorphometric analysis, zoological activity


1996 ◽  
Vol 40 (1-2) ◽  
pp. 3-23 ◽  
Author(s):  
K. Weaich ◽  
A. Cass ◽  
K.L. Bristow

2003 ◽  
Vol 83 (2) ◽  
pp. 305-312 ◽  
Author(s):  
A. B. Kwabiah

Yield of silage corn (Zea mays L.) in Newfoundland (NL), Canada, is limited by low corn heat units (CHU). This is a reflection of generally moderate temperature throughout the growing season in addition to having a late spring and early fall. Clear photo-degradable plastic film, applied to the soil after sowing, may boost soil and air temperatures and hence advance growth and development. Research was conducted at three on -farm sites near St. John’s in 2000 and 2001 to determine the effects of plastic mulch on time from planting to emergence (VE), 50% silking (R1), 50% kernel milk line (R5.5) and dry matter (DM) yield. Three early hybrids with CHU ratings of 2100, 2200 and 2300 were planted in late May of each year when the soil temperature was above 10°C. At planting, half of each plot was covered (PC) with a clear photo-degradable plastic film (X-Tend Plastic System®), 1.32 m in width and 6 m thick, and the other half was not covered (NC). During the first 30–35 d after planting, the crops grew under the thin plastic mulch before breaking through as it started to degrade. During this time, air (10 cm above soil surface) and soil (5 cm depth) temperatures underneath the plastic film were recorded. These were compared to the soil (5 cm depth) and air (100 cm high) temperatures of the NC plots. Soil and air temperatures for PC plots were consistently higher than for NC plots in both years. The plastic continued to degrade during the rest of the season and was completely degraded by the time of harvest in late `September. In 2000, the plastic advanced VE by 9 to 13 d, R1 by 10 to 15 d and R5.5 by 9 to 15 d relative to the NC treatment. In 2001, advancement of VE due to the plastic mulch ranged from 8 and 12 d, 6 to 9 d for R1 and 6 to 11 d for R5.5. Relative to the NC treatment, the plastic improved CHU by 9% and total DM yield by 22% in 2000 and improved CHU by 7% and total DM yield by 14% in 2001. A small increase in CHU due to plastic mulch resulted in a proportionately larger increase in total DM yield. Plastic mulches have the potential to accelerate maturity thereby insuring silage corn crops achieve acceptable DM yields in cool climate regions such as Newfoundland. Key words: Air temperature, corn heat units, soil temperature, total DM yield


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Lixin Wang ◽  
Huamin Liu ◽  
Yuhong Liu ◽  
Jianwei Li ◽  
Hongbo Shao ◽  
...  

In recent decades, degradation of ecosystem in the steppe region of the Inner Mongolia Plateau, especially in riparian floodplain wetlands, has become a significant ecological crisis. Not uncommonly, with the increasing of livestock in the Inner Mongolian steppe region, a riparian floodplain wetland is becoming a hotspot area of grazing for local herdsmen. Hence, it is essential to understand degradation mechanisms of riparian floodplain wetland ecosystems caused by extensive grazing. In this study, the spatial distribution of soil compaction, salinity, total nitrogen, total phosphorus, organic carbon, and microbial biomass C and N were investigated. The results showed that grazing led to an increase in soil compaction and soil surface salinity, which significantly lowered levels of total N, P, and TOC in the soil surface. Grazing decreased soil microbial biomass C and N concentration in the lower riparian floodplain wetland, whereas it significantly increased soil microbial biomass C and N concentration in the higher riparian floodplain wetland. Elevation differences in the riparian floodplain wetland increased spatial heterogeneity in the soil and thus resulted in different influence of grazing on wetland soils and ecosystem. Therefore, elevation differences and grazing intensity were the main factors controlling soil characteristics in the riparian floodplain wetland of this region.


1970 ◽  
Vol 50 (3) ◽  
pp. 379-384 ◽  
Author(s):  
J. W. KETCHESON

Interacting effects of controlled heat from electric heating cables 15 cm below the surface and of polystyrene insulation on the soil surface were studied over four seasons on an imperfectly drained outwash soil at Guelph, Canada. Heating to 22 C advanced germination of corn (Zea mays L.) by three days, improved emergence, advanced growth and increased yield at maturity. Insulation retarded germination, early growth and silking, but increased yields in three of the four years. Where heating decreased ear moisture content at harvest, insulation increased it. Heat combined with insulation gave the greatest response in growth, advance in silking, and increase in yield. The season with favorable soil temperature combined with low air temperature gave the highest yield of the four years. Fertilizer banded near the seed at planting advanced development and increased yields, but did not produce a statistically significant interacting effect with heat and insulation. However, fertilizer phosphorus uptake early in the season was markedly increased by heat and insulation. It was concluded that insulation can favor yield, provided that soil temperature is maintained near optimum.


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