Previous Corn Row Effects on Potassium Nutrition and Yield of Subsequent No‐Till Soybeans

Abstract

Narrow‐row soybean [Glycine max (L.) Merr.] production in corn [Zea mays L.]–soybean rotations results in various distances of soybean rows from previous corn rows, yet little is known about soybean responses to proximity to prior corn rows in no‐till systems. The objective of this study was to evaluate the impacts of preceding corn rows on potassium (K) nutrition and yield of subsequent no‐till soybeans. Four field experiments involving a corn–soybean rotation were conducted on long‐term no‐till fields with low to medium K levels from 1998 to 2000 near Paris and Kirkton, Ontario, Canada. In the corn year, treatments included K application rate and placement in conjunction with tillage systems or corn hybrids. Before soybean flowering, soil exchangeable K concentrations (0–20 cm depth) in previous corn rows were significantly higher than those between corn rows. At the initial flowering stage, trifoliate leaf K concentrations of soybeans in preceding corn rows were 2.0 to 5.3 g kg^?1 higher than those from corresponding plants between corn rows. Yield of no‐till soybeans in previous corn rows increased 10 to 44% compared to those between previous corn rows. Positive impacts of prior corn rows on soil K fertility, soybean leaf K, and soybean yield occurred even when K fertilizer was not applied in the prior corn season. Deep banding of K fertilizer tended to accentuate row vs. between‐row effects on soybean leaf K concentrations in low‐testing soils. Corn row effects on soybeans were generally not affected by either tillage system or corn hybrid employed in the prior corn crop. Potassium management strategies for narrow‐row no‐till soybeans should take the potential preceding corn row impacts on soil K distribution into account; adjustments to current soil sampling protocols may be warranted when narrow‐row no‐till soybeans follow corn on soils with low to medium levels of exchangeable K.     

Soybean growth and yield response to residual fertilizer phosphorus bands

Residual effects on soybeans (Glycine max L.) from phosphrous (P) fertilizer bands applied 5 cm to the side and 5 cm below the seeds of a preceding corn (Zea mays L.) crop on a Brandt silt loam soil (fine‐silty, mixed Udic Haploboroll) were studied after an intervening no‐till fallow period. The P rates applied were 0, 12, 24, and 49 kg P ha^‐1. Soybean rows were planted as close as possible to the preceding corn rows. Soybean tissue was sampled at the early bloom stage in each row of the paired‐row design. Twenty soil column (2.5x3 cm) samples were collected from the 0–15 cm depth along a 50‐cm‐long trench that bisected a soybean row. The distance of the previous P band (column with the highest extractable Bray‐I P level) from the soybean row became a variable in this experiment with category range distances of <6 cm, 6–9 cm, and >9 cm from band to row. Residual P from all application rates increased shoot dry matter weight, shoot P uptake, and to a lesser extent grain yield in comparison to the unfertilized soybeans. Distance of the P band from the row was more important than the P concentration in the band. Shoot P uptake and grain yield were significantly larger for fertilized compared to unfertilized soybeans when the band distance was less than 9 cm from the row. Residual P band distance of greater than 9 cm from the row had little effect on soybean growth and yield.     

Role of wheel tracks in runoff generation and erosion under vegetable production on a clay loam soil at Pukekohe, New Zealand

The effects of wheel traffic on soil surface hydraulic properties, and consequent effects on erosion, following planting of vegetable crops in beds have not been widely studied. This paper describes two trials to quantify how wheel tracks influence infiltration and erosion rates, and assesses the value of cultivating wheel tracks for reducing erosion. The trials were carried out under natural rainfall, on Dystric Nitosols with clay loam texture and strong, stable structure. Net rates of erosion from onion (Allium cepa L.) beds with cultivated or uncultivated inter-bed wheel tracks were measured with erosion pins and repeat topographic surveys of sediment trapped in silt fences. Infiltration rates in onion beds, cultivated and uncultivated wheel tracks, and changes in infiltration rates through winter, spring, and summer, were measured using the double-ring, ponded-water method.

Differences in erosion rate were only measured in the second trial in which erosion rate from the uncultivated treatment was 21 Mg ha⁻¹, compared to 1 Mg ha⁻¹ for the cultivated treatment. Erosion occurred through mobilisation of soil along the edge and base of the wheel tracks, with no evidence of erosion of the onion beds. Most of the eroded soil comprised soil aggregates, with 75% between 0.25 and 4 mm in diameter, suggesting soil was transported in runoff along the wheel tracks as stable aggregates. Uncultivated wheel tracks had very low infiltration rates compared to onion beds and cultivated wheel tracks. The differences in infiltration rates between cultivated and uncultivated wheel tracks were consistent in both trials, with minor differences due to rainfall patterns and the implements used to cultivate wheel tracks. There were clear trends in infiltration rates through time, with rates in the uncultivated wheel tracks increasing during the growing season from 1.4×10⁻⁷ to 2.1×10⁻⁵ ms⁻¹ and in onion beds from 1.1×10⁻⁴ to 2.5×10⁻⁴ ms⁻¹, while rates in the cultivated wheel tracks decreased from 1.7×10⁻² to 2.4×10⁻³ ms⁻¹. The major increase of infiltration rate in uncultivated wheel tracks occurred after October when the soil surface began to dry out, and frequent wetting and drying cycles caused the compacted surface soil to crack. Most erosion occurred in the winter/early spring period when storm frequency and rainfall intensity was highest, and infiltration rates in the uncultivated wheel tracks lowest. Cultivating wheel tracks is a simple and effective practice to increase infiltration of rainfall and reduce erosion rates on clay-rich, strongly structured soils.     

The effects of wheel-induced soil compaction on anchorage strength and resistance to root lodging of winter barley (Hordeum vulgare L.)

Lodging is the permanent displacement of cereal stems from the vertical. Cereal plants growing in the edge rows next to both wheel tracks (‘tramlines’) and the gaps between experimental plots (‘inter-plot spaces’), which are traversed by farm vehicles during planting operations and agrochemical application, are less prone to lodge than plants growing elsewhere in fields and plots. Previous research has attributed this phenomenon to an increase in the stem strength of edge row plants, and hence their resistance to stem lodging, resulting from reduced competition between edge row plants for resources. However, this explanation gives no consideration to the anchorage strength of edge row plants, and hence their resistance to root lodging. Differences in soil and plant characteristics between the edge and centre rows of plots of winter barley (Hordeum vulgare L.) were examined on sand, silt and clay dominated soil types. Edge rows next to tramlines were investigated on the silt and clay soil types, whereas edge rows next to inter-plot spaces were investigated on the sand soil type. Edge row plants next to both tramlines and inter-plot spaces had 58.8% greater anchorage strength and hence resistance to root lodging than centre row plants. This was attributed to (1) greater soil compaction in the edge rows resulting from wheel traffic in the tramlines and inter-plot spaces, which increased the strength of the soil matrix surrounding the roots, and (2) greater plant root growth in the edge rows resulting from reduced competition. Bulk density, root plate spread and structural rooting depth were 19, 22, and 12% greater, respectively, in the edge rows of all soil types. The results suggest that in order to reduce lodging risk, energies should be directed towards identifying agricultural practices that optimise soil compaction in the seedbed without causing significant limitations to root growth.     

Plant density,distribution, and fertilizer effects on yield and quality of irrigated corn silage

Abstract

Grain deficits frequently occur in the Southeastern Atlantic Coastal Plain because erratic rainfall patterns and soil properties often limit corn (Zea mays L.) yields, however, harvesting corn for silage may enable farmers to produce a second grain crop during the same calendar year. Effects of row spacing, plant population, and fertilizer program on yield, quality, and mineral concentrations of corn silage grown with irrigation on Typic Paleudult soils were therefore investigated. Two plant population treatments which averaged 7.0 and 10.1 plants m^‐2 were evaluated with two fertilizer programs that differed in N, N and K, and N, P, and K in 1980, 1981, and 1982, respectively. Each plant density by fertilizer combination was evaluated in single rows spaced 96 cm apart and in twin rows which approximately doubled the intrarow plant spacing. Plot size for the 2×2×2 factorial experiment ranged from 30 to 44 m². Yield, quality, and mineral concentrations of corn silage grown in single rows spaced 96 or 75 cm apart and twin rows were also evaluated in large (185 m²) plots under center pivot irrigation during 1981 and 1982.

Dry matter yields of 22 to 26 Mg ha^‐1 were achieved with plant densities of 6.7 to 13.5 plants m^‐2 at both experimental sites. Highest silage yields were produced with stand densities of 9 m or more planted in single 75 cm or twin rows, but yield differences were statistically significant at P(0.05) in only two of five site years. Increasing total N‐P‐K application beyond 200–30–167 kg ha”; increased crude protein slightly in 1980 and significantly in 1981 and 1982. Concentrations of Mn and Zn in silage were increased by higher fertilization, presumably because nitrification reduced surface soil pH and increased their availability. Dry matter yield, fiber, energy, and other mineral nutrients were not significantly influenced by fertilizer program. These experiments identified management practices for the Atlantic Coastal Plain which resulted in corn silage yields equal to those produced in the cooler mountain region of Georgia and that exceeded current average production in South Carolina by approximately 40% without reducing apparent feed quality.     

Sustaining Soil Quality with Legumes in No‐Tillage Systems

Abstract

Tillage, cropping system, and cover crops have seasonal and long‐term effects on the nitrogen (N) cycle and total soil organic carbon (C), which in turn affects soil quality. This study evaluated the effects of crop, cover crop, and tillage practices on inorganic N levels and total soil N, the timing of inorganic N release from hairy vetch and soybean, and the capacity for C sequestration. Cropping systems included continuous corn (Zea mays L.) and stalk residue, continuous corn and hairy vetch (Vicia villosa Roth), continuous soybeans (Glycine max L.) plus residue, and two corn/soybean rotations in corn alternate years with hairy vetch and ammonium nitrate (0, 85, and 170 kg N ha^?1). Subplot treatments were moldboard plow and no tillage. Legumes coupled with no tillage reduced the N fertilizer requirement of corn, increased plant‐available N, and augmented total soil C and N stores.     

Interactive effects of wheel‐traffic and tillage system on soil carbon and nitrogen

Abstract

Wheel‐traffic induced soil compaction has been shown to limit crop productivity, and its interaction with tillage method could affect soil nutrient transformations. A study was conducted during 1993–1994 to determine interactive effects of tillage method (conventional tillage and no‐tillage) and wheel‐traffic (traffic and no traffic) on soil carbon (C) and nitrogen (N) at a long‐term (initiated 1987) research site at Shorter, Alabama. The cropping system at this study site is a corn (Zea mays L.) ‐ soybean [Glycine max (L.) Merr] rotation with crimson clover (Trifolium incarnatum L.) as a winter cover crop. Soil organic C, total N, and microbial biomass carbon (MBC) were not significantly affected by six years of traffic and tillage treatments. However, conventional tillage compared to no‐tillage almost doubled the amount of CO₂‐C respired over the entire observation period and during April 1994 field operations. Soil respiration was stimulated immediately after application of wheel‐ traffic, but nontrafficked soils produced greater amounts of CO₂‐C compared to trafficked soils during other periods of observation. Nitrogen mineralization was significantly lower from no‐tillage‐trafficked soils compared to conventional tillage‐trafficked and no‐tillage‐nontrafficked soils for the 1993 growing season. A laboratory incubation indicated the presence of relatively easily mineralizable N substrates from conventional tillage‐trafficked soil compared to conventional tillage‐nontrafficked and no‐till‐trafficked soils. For the coarse textured soil used in this study it appears that conventional tillage in combination with wheel‐traffic may promote the highest levels of soil microbial activity.     

Cover crop nitrogen availability to conventional and no‐till corn: Soil mineral nitrogen,corn nitrogen status,and corn yield

Abstract

Understanding seasonal soil nitrogen (N) availability patterns is necessary to assess corn (Zea mays L.) N needs following winter cover cropping. Therefore, a field study was initiated to track N availability for corn in conventional and no‐till systems and to determine the accuracy of several methods for assessing and predicting N availability for corn grown in cover crop systems. The experimental design was a systematic split‐split plot with fallow, hairy vetch (Vicia villosa Roth), rye (Secale cereale L.), wheat (Triticum aestivum L.), rye+hairy vetch, and wheat+hairy vetch established as main plots and managed for conventional till and no‐till corn (split plots) to provide a range of soil N availability. The split‐split plot treatment was sidedressed with fertilizer N to give five N rates ranging from 0–300 kg N ha^‐1 in 75 kg N ha^‐1 increments. Soil and corn were sampled throughout the growing season in the 0 kg N ha^‐1 check plots and corn grain yields were determined in all plots. Plant‐available N was greater following cover crops that contained hairy vetch, but tillage had no consistent affect on N availability. Corn grain yields were higher following hairy vetch with or without supplemental fertilizer N and averaged 11.6 Mg ha^‐1 and 9.9 Mg ha^‐1 following cover crops with and without hairy vetch, respectively. All cover crop by tillage treatment combinations responded to fertilizer N rate both years, but the presence of hairy vetch seldom reduced predicted fertilizer N need. Instead, hairy vetch in monoculture or biculture seemed to add to corn yield potential by an average of about 1.7 Mg ha^‐1 (averaged over fertilizer N rates). Cover crop N contributions to corn varied considerably, likely due to cover crop N content and C:N ratio, residue management, climate, soil type, and the method used to assess and assign an N credit. The pre‐sidedress soil nitrate test (PSNT) accurately predicted fertilizer N responsive and N nonresponsive cover crop‐corn systems, but inorganic soil N concentrations within the PSNT critical inorganic soil N concentration range were not detected in this study.     

Use of Spent Mushroom Substrate (SMS) for Corn (Maize) Production and its Effect on Surface Water Quality

Mushroom farmers have large quantities of spent mushroom substrate after their crops are harvested. This material is used for a variety of purposes including the growth of field crops. SMS was incorporated into a poor quality soil before planting 90-day corn. Field plots were established where spent mushroom substrate (SMS) was incorporated at 22.5, 45.0 or 90.0 kg m^?1, plus an untreated control on each of three years. Analysis of SMS indicates its nutrient level was 0.9-0.6-1.0 (N-P-K). Starter fertilizer was applied at planting along with an insecticide, but no herbicide. No additional fertilizer was used. Corn yields were significantly higher in SMS amended plots and the nitrogen content of both grain and stover was significantly higher than the control. Surface runoff water quality values from SMS amended soil were in the same range as those from the control treatments, the plots that received no SMS. Annual incorporation of up to 90 kg m^?2 of SMS into land planted to corn did not degrade the quality of surface water. Nutrients were retained in the SMS soil matrix and were, apparently, used as nutrients by the corn plants. Surface runoff was very low in ammonia nitrogen, CBOD, and chlorides. Use of SMS as an exclusive soil nutrient/soil ameliorant in corn production resulted is exceptionally good yields and quality.     

Effects of tillage, weed control method and row spacing on soybean yield and certain soil properties

Soybean (Glycine max (L.) Merr.) is an important crop in the southeastern United States, and thus there is a need for additional information on the effects of tillage, weed control methods and row spacing on soybean yields, weed populations and soil properties. The objective of this study was to determine the effects of three weed control methods (none, cultivation, and herbicide) and three row spacings (45, 60 and 90 cm) on soybeans planted in a conventionally prepared seedbed or planted in wheat stubble (no-till (NT)) on a Decatur silty clay loam (Rhodic Paleudult) soil during the 1987 and 1988 growing seasons. Following NT planting, soybean plots produced a seed yield of 3102 kg ha⁻¹ with herbicide, 2911 kg ha⁻¹ with cultivation and 2216 kg ha⁻¹ with no weed control. On a conventionally prepared seedbed, herbicide and cultivation resulted in almost equal seed yields (3898 kg ha⁻¹ and 3954 kg ha⁻¹ respectively) which were significantly higher than those from the no weed control plots (3151 kg ha⁻¹). Soybeans in narrow (45 cm) rows (3997 kg ha⁻¹) consistently out-yielded those in the wider 60 cm rows (3130 kg ha⁻¹) and 90 cm rows (2490 kg ha⁻¹) in both growing seasons, results averaged across years showed that conventionally planted soybeans produced higher yields (3668 kg ha⁻¹) than NT planted soybeans (2743 kg ha⁻¹). The weed infestation was significantly less with herbicide or cultivation than with no weed control and also less in narrow rows (45 cm) than in wider rows (60 and 90 cm). Data on the soil properties (from a depth of 0–15 cm) showed that moisture content, organic matter content and total soil nitrogen were higher in NT plots than in conventional plots. Similarly, disease ratings and infestation of bacterial blight of soybean were significantly higher in NT than in conventional tillage systems.     

Traffic and residue management systems: effects on fate of fertilizer N in corn

Soil compaction has been recognized as a problem limiting crop production, especially in the Southern Coastal Plain of the USA. Development of tillage and residue management systems is needed to alleviate soil compaction problems in these soils. Fertilizer nitrogen (N) management is also an important factor in these management systems. In 1988, a study was initiated with a wide-frame (6.3 m) vehicle to determine the interactive effects of traffic, deep tillage, and surface residue management on the fate of fertilizer N applied to corn (Zea mays L.) grown on a Norfork loamy sand (fine-loamy, siliceous, Thermic, Typic Kandiudults). Corn was planted into a winter cover crop of ‘Tibbee’ crimson clover (Trifolium incarnatum L.). Treatments included: traffic (conventional equipment or no traffic); deep tillage (no deep tillage, annual in-row subsoiling, or one-time only complete disruption); residue management (no surface tillage or disk and field cultivation). The one-time only complete disruption was accomplished by subsoiling at a depth of 43 cm on 25 cm centers in spring 1988. In 1990–1991, fertilizer applications were made as ¹⁵N-depleted NH₄NO₃ to microplots inside each treatment plot. The 1990 and 1991 data are reported here. In 1990 an extreme drought resulted in an average grain yield of 1.8 Mg grain ha⁻¹, whereas abundant rainfall in 1991 resulted in 9.4 Mg grain ha⁻¹. Deep tillage increased corn dry matter production in both years. In 1991, grain yields indicated that corn was susceptible to recompaction of soil owing to traffic when residues were incorporated with surface tillage. In the dry year, plant N uptake was increased 27% with deep tillage and decreased 10% with traffic. In the wet year, a surface tillage × deep tillage × traffic interaction was observed for total N uptake, fertilizer N uptake, and total fertilizer N recovery in the plant-soil system. When combined with traffic, plant N uptake was reduced with the highest intensity tillage treatment (135 kg N ha⁻¹) because of rootrestricting soil compaction, and with the lowest intensity tillage treatment (129 kg N ha⁻¹) because of increased N losses. In these soils, leaving residues on the soil surface can reduce the detrimental effect of traffic on corn production, but if no surface tillage is performed, deep tillage is needed.     

Relationships between relative crop yields,soil test phosphorus levels,and fertilizer requirements for phosphorus

Abstract

More uniformity in methods of deriving fertilizer P recommendations from crop response data should improve accuracy and precision of fertilization rates. Experimental data that relate crop yields to soil test levels and describe the effect of fertilizer P on soil test levels provide the basis for determining fertilization rates for specific crop‐soil situations. A modification of the Mitscherlich equation was used in derivation of a new equation for calculating fertilizer P requirements as a function soil test levels of P. The equation was applied to response data for 4 crops.

Response curves and fertilizer requirements as calculated for corn, soybeans, alfalfa, and clover‐grass indicated that soybeans yielded relatively more than the other three crops at low soil test levels of P. Corn and alfalfa required higher soil test levels to reach 95% maximum yield and required higher rates of fertilizer P when initial test levels were low.     

Use of velvet bean to improve soil fertility and weed control in corn production in northern belize

Abstract

The objective of this research was to mesasure the effect of intercropping corn (Zea mays L.) with velvet bean (Mucuna pruriens) oil corn yields, soil fertility, and weed control in northern Belize. Two soils were used which are widespread in the area. These soils are high in clay (simectitc) and are well supplied with bases. One soil, the Louisville, has a black surface horizon overlying light gray to white calcareous weathered coral. The other soil was Xaibe which consists of a reddish‐brown clay over hard limestone “cap rock”; at 30–40 cm. Both soils had a relatively high organic carbon (C) and total nitrogen (N) content. We classified the Louisville as Calciustert and the Xaibe as a Ustropept. The treatments used (carried out annually in 1990, 1991, and 1992) were residue burn (B), bum plus fertilizer (BF), a velvet bean intercrop (G), and a velvet bean intercrop plus fertilizer (GF). Velvet bean intercropping did not have a positive effect on corn yields on these soils. For adequate yields to be maintained, it appears that fertilization with N, phosphorus (P), potassium (K) and certain micronutrients are required. We did obtain some indication that velvet bean intercropping will reduce weed population, including a serious infestation of cogongrass (Jmperata cylindrica). Velvet bean did not maintain the soil N content Corn yields decreased on the Louisville soil at San Victor from a range of 2,804 kg/ha to 3,181 kg/ha in 1990 to 1,783 kg/ha to 2,065 kg/ha in 1992. There were no significant treatment effects in any year. With the Xaibe soil, no yields were obtained in 1990 because of weed competition. In 1991, yields ranged from 555 kg/ha to 1,146 kg/ha (no significant treatment effects). In 1992, the fertilized plots, BF and GF, had corn yields of 1,391 kg/ha and 1,592 kg/ha, respectively. The unfertilized plots, B and G, had corn yields of 751 kg/ha and 699 kg/ha, respectively. We did obtain sufficient information valuable for persons making fertilizer recommendations on similar types of soil. The Mehlich 3 and the ammonium bicarbonate‐DTPA extractant (the latter extractant similar to that used in Belize) did not give good correlations between P and K leaf levels and corn yields. Where soil test P and K were often adequate, corn ear leaf levels were deficient (and presumably yields were reduced because of this metabolic deficiency). We concluded from both soil tests and leaf analyses that the micronutrients copper (Cu), manganese (Mn), and molybdenum (Mo) are seldom, if ever, limiting plant growth and grain yield, although there appears to be seasonal differences. With both soils, soil tests were not good indicators of zinc (Zn) concentrations in the leaf. In 1992, soil tests indicated adequacy of this element, although leaf Zn was deficient in all plots on the Louisville soil in 1990, most plots in 1992, and several plots on the Xaibe soil in both years.     

Organically fertilized onions (Allium cepa L.): effects of the fertilizer placement method on quercetin content and soil nitrogen dynamics

Field-cured onions cv. Hyskin ( Allium cepa L.) supplied with organic nitrogen fertilizer were studied. The fertilizer was applied by broadcasting and harrowing, broadcasting and rotary cultivation, or placement between rows. Nitrogen dynamics were monitored throughout the growing season by soil sampling. Variation in quercetin content in the onion scales was analyzed by HPLC. The organically fertilized onions were compared with inorganically fertilized onions grown in the same field. Inoculation with arbuscular mycorrhizal fungi (AMF) in the row at sowing or during commercial transplant production was tested but did not significantly affect mycorrhizal root colonization levels in the field. Onions that received no fertilizer at all or that had fertilizer placed between rows had better establishment, probably due to more favorable soil nitrogen concentrations for seedling emergence. Broadcast application led to higher nitrogen concentration in the root zone, resulting in fewer but larger individual onions. Quercetin levels were not significantly altered as a result of nitrogen fertilizer source (inorganic or organic), application method, or mycorrhizal inoculation. However, variation between years was significant, with quercetin levels in 2004 almost twice as high as those in 2005.     

2FHF-4.56型宽行距作物基肥对行分层深施机设计与试验

针对当前西北干旱地区宽行距作物种植过程中施肥方式不科学,传统撒施肥料用量大、利用率低,该研究结合作物种植农艺特点,提出在作物行方向进行基肥分层深施措施,并研制了基肥对行分层深施机,对仿形单体进行设计,分析了仿形单体的运动学和力学特性,确定了仿形单体质量和仿形弹簧型号。同时研制了一种基于雄性蜣螂头部角状突起的仿生开沟铲,得到仿生开沟铲刃轮廓曲线拟合方程,确定了仿生开沟铲结构及工作参数。通过土槽试验优化了仿生开沟铲前刃角,得出前刃角最佳角度为65°,此时仿生铲相对传统铲的开沟阻力减小42.6%,对土壤的扰动明显减小。样机田间试验表明,分层施肥作业对行精度偏差平均值为2.7 cm,6组施肥铲浅层肥料深度平均值为12.44 cm,浅层施肥深度一致性变异系数为6.12%;深层肥料深度平均值为20.49 cm,深层施肥深度一致性变异系数为4.98%。施肥模式对比试验表明,对行分层施肥的植株长势更好,棉果枝数和单株铃数更多,根系发育更为良好,肥料减施25%,同时棉花平均每公顷增产8.9%,玉米平均每公顷增产8.6%,研究结果表明,对行分层深施肥具有较好的减肥增效作用,对推进棉花生产科学施肥具有重大价值和现实意义。     

Border row effect on corn grain response to sidedressed nitrogen fertilizer

Abstract

Nitrogen (N) fertilizer recommendations for corn (Zea mays L.) are normally developed from field experiments that determine yield response to applied N. The objective of this study was to examine the severity of border row competition with the harvest rows for sidedressed N in field experiments measuring grain yield. This study was conducted in 1993 and 1994 on a Sharpsburg silty clay loam (fine, montmorillonitic, mixed, mesic argiudoll). Ammonium nitrate was broadcast to the center two rows of a four row plot, all four rows of a four row plot and all six rows of a six row plot. Results showed that grain yield from four and six row plots were similar and indicated that while grain yields were much less in 1993 than 1994 (7.36 versus 12.06 Mg ha^‐1, respectively), corn yield response to N was similar regardless of the number of rows fertilized. Thus, there is little reason for plots larger than four rows. The results also lend credibility to sidedressing only harvest rows for soil test calibration studies where grain yield response is the primary response variable.     

High Rate of Nitrogen Fertilization Increases the Crop Water Stress Index of Corn under Soil Drought

Soil nitrogen (N) availability is dominated by soil water regime and the N fertilizer levels, which affect crop growth in soil water stress. To determine the optimum N applications under different degrees of soil drought, this study investigated the effects of N fertilizer levels on the crop water stress index (CWSI) of summer corn under soil water stress. A 2-year field experiment was conducted in waterproof plots in upland red soils in subtropical China. Three N fertilizer levels and seven soil water deficit levels were employed in 2007 and 2008. Nitrogen fertilization had no influence on the CWSI of the corn under slight to moderate soil drought, but the high-N treatment increased the CWSI significantly (P < 0.01) under soil drought when the mean CWSI exceeded ～0.20. The results suggested that for scheduling irrigation or predicting crop yields, the equations between CWSI and yield should be established on comparable N fertilization levels.     

Soil Quality of a Mature Alley Cropping Agroforestry System in Temperate North America

Long-term effects of alley cropping on soils in the temperate zone are not widely known. Management, landscape, and soil depth effects on soil physical and biological properties were examined in a silver maple (Acer saccharinum L.) no-till corn (Zea mays L.)- soybean (Glycine max L.) rotation established in 1990 in northeast Missouri. Soils from crop alleys and tree rows were collected along transects traversing upper to lower landscape positions at three depths. Fluorescein diacetate hydrolase (FDA), β-glucosidase, β-glucosaminidase, and dehydrogenase activities were measured. Soil bulk density, aggregate stability, carbon (C), nitrogen N), and enzyme activities decreased with soil depth in alley and tree rows except for glucosaminidase. Soil physical and biological parameters did not differ significantly between alley and tree row. Landscape position effects were not significant for management or depth. Tree establishment improves soil quality in the crop alley as the system matures with improvements extended throughout the soil profile.     

Effect of combined water and nutrient management on runoff and sorghum yield in semiarid Burkina Faso

Abstract. In the semiarid regions of sub-Saharan Africa, fertilizer recovery and nutrient release from organic sources are often moisture limited. Moreover, in these regions runoff brings about large nutrient losses from fertilizer or organic inputs. This study was conducted in the north sudanian climate zone of Burkina Faso (annual rainfall 800 mm, PET 2000 mm yr⁻¹). We assessed the combined and interactive effects of two types of permeable barriers (stone rows and grass strips of Andropogon gayanus Kunth cv. Bisquamulatus (Hochst.) Hack .) and organic or mineral sources of nitrogen on erosion control and sorghum yield. The field experiment (Ferric Lixisol, 1.5% slope) was carried out during three rainy seasons and consisted of 2 replications of 9 treatments, in which the barriers were put along contours and combined with compost, manure and fertilizer nitrogen (N). Compared with the control plots, the average reduction in runoff was 59% in plots with barriers alone, but reached 67% in plots with barriers + mineral N and 84% in plots with barriers + organic N. On average, stone rows reduced soil erosion more than grass strips (66% versus 51%). Stone rows or grass strips without N input did not induce a significant increase of sorghum production. Supplying compost or manure in combination with stone rows or grass strips increased sorghum grain yield by about 142%, compared with a 65% increase due to mineral fertilizers. The sorghum grain yields at 1 m upslope from the grass strips were less than those 17 m from the grass strips. As stones do not compete with plants, the opposite trend was observed with stone rows. We conclude that for these nutrient depleted soils, permeable barriers improve nutrient use efficiency and therefore crop production. However, grass strips must be managed to alleviate shade and other negative effects of the bunds on adjacent crops.     

Residual soil nitrogen credits for corn production along the upper Texas Gulf Coast region

Studies were conducted to evaluate response of dryland corn (Zea mays L.) along the upper Texas Gulf Coast to residual soil nitrate-nitrogen (NO₃-N) measured to depths of 15, 30, and 61 cm. Residual soil NO₃-N levels ranged from 3.4 to 31.6, 7.8 to 49.3, and 9.0 to 71.7 kg ha^?1, respectively, in 0 to 15, 15 to 30, and 30 to 61 cm depth increments, with cumulative NO₃-N ranging from 23.5 to 114.5 kg ha^?1 across sites-years. Where N fertilizer was reduced due to N crediting, yields and bushel weights at all 13 site-years showed no difference from those receiving full recommended N rates. A yield response to any level of added fertilizer N above the control was observed for only 6 of 13 site-years. These results indicate a high potential for success in crediting carryover soil NO₃-N to 61 cm as a means of reducing applied nitrogen fertilizer rates.