Effects Of Fertilizer Placement Research Articles

Deep placement of nitrogen fertilizer in autumn improves N utilization by spring tea (Camellia sinensis L.)

AbstractBackgroundThe efficient use of fertilizers depends very much on their proper placement, and the effects of fertilizer placement on the woody perennial plant tea (Camellia sinensis L.) are not clearly understood.MethodsA 15N mini‐plot field experiment was conducted to investigate the effects of four common techniques of fertilizer placement techniques. 15N‐labeled urea was applied in October by surface broadcasting, surface broadcasting with 3–5 cm soil incorporation, shallow (3–5 cm), and deep (10–15 cm) side dressing (DSD). The proportion of N derived from 15N‐labeled fertilizer (Ndff%) was estimated in root, and soil samples were collected 15 and 43 days after fertilization (DAA15 and DAA43) and in young shoots collected in the following spring.ResultsMost fertilizer 15N was located in the soil near the placement position at DAA15 and 15N had moved downward but maintained a similar distribution in the soil profile at DAA43. The distribution of fibrous root Ndff% in the soil profile was very similar to that of soil Ndff%. DSD resulted in the highest shoot Ndff%, the estimated amount of 15N in young shoot derived from 15N‐label fertilizer (shoot 15N), and its percentage related to the amount of 15N‐labeled fertilizer input (REFN%). Thus, DSD of urea as basal application in autumn maintained a higher and prolonged N supply in the middle and deep soil layers, thereby improving fertilizer‐N absorption and utilization in the following spring tea. However, direct broadcasting of urea on the soil surface resulted in low N availability in the soil and utilization by tea plants.ConclusionOur results demonstrate that DSD of N fertilization should be recommended for tea planting to increase N use efficiency and reduce environmental losses in forms of runoff and volatilization.

Soil Water Deficit and Fertilizer Placement Effects on Root Biomass Distribution, Soil Water Extraction, Water Use, Yield, and Yield Components of Soybean [Glycine max (L.) Merr.] Grown in 1-m Rooting Columns.

Typical small-pot culture systems are not ideal for controlled environment phenotyping for drought tolerance, especially for root-related traits. We grew soybean plants in a greenhouse in 1-m rooting columns filled with amended field soil to test the effects of drought stress on water use, root growth, shoot growth, and yield components. There were three watering treatments, beginning at first flower: watered daily to 100% of the maximum soil water holding capacity (control), 75% (mild drought stress), or 50% (drought stress). We also tested whether applying fertilizer throughout the 1-m soil depth instead of only in the top 30 cm would modify root distribution by depth in the soil profile and thereby affect responses to drought stress. Distributing the fertilizer over the entire 1-m soil depth altered the root biomass distribution and volumetric soil water content profile at first flower, but these effects did not persist to maturity and thus did not enhance drought tolerance. Compared to the control (100%) watering treatment, the 50% watering treatment significantly reduced seed yield by 40%, pod number by 42%, seeds per pod by 3%, shoot dry matter by 48%, root dry matter by 53%, and water use by 52%. Effects of the 75% watering treatment were intermittent between the 50 and 100%. The 50% treatment significantly increased root-to-shoot dry matter ratio by 23%, harvest index by 17%, and water-use efficiency by 7%. Seed size was not affected by either fertilizer or watering treatments. More than 65% of the total root dry matter was distributed in the upper 20 cm of the profile in all watering treatments. However, the two drought stress treatments, especially the mild drought stress, had a greater proportion of root dry matter located in the deeper soil layers. The overall coefficient of variation for seed yield was low at 5.3%, suggesting good repeatability of the treatments. Drought stress imposed in this culture system affected yield components similarly to what is observed in the field, with pod number being the component most strongly affected. This system should be useful for identifying variation among soybean lines for a wide variety of traits related to drought tolerance.

Fertilizer placement effects on eclipta (Eclipta prostrata) growth and competition with container-grown ornamentals

AbstractThe objective of this study was to determine the effect of fertilizer placement on the growth of eclipta [Eclipta prostrata (L.) L.] and evaluate its interference with container-grown ornamental plants, including Japanese boxwood (Buxus microphylla Siebold & Zucc.) and ligustrum (Ligustrum lucidum W.T. Aiton). Results indicated that subdressing reduced E. prostrata shoot weight by 28%, 42%, and 46% at depths of 2.5, 5.0, and 7.5 cm, respectively, in comparison with a topdressed fertilizer treatment (a standard industry practice). Presence of E. prostrata reduced the growth of both ornamental species. Ligustrum shoot weight decreased as subdressing depth increased, while boxwood growth was most notably reduced at the 7.5-cm depth in comparison with topdressed containers. Overall, results indicated that subdressing may be an effective weed management strategy, but subdressing depth needs to be based on initial liner size to prevent possibly delays in production time.

Effects of Fertilizer Placement on Greenhouse Gas Emissions from a Sun and Shade Grown Ornamental Crop1

Abstract The level to which ornamental plant production impacts rising atmospheric greenhouse gas (GHG) concentrations remains unknown. Research to date has focused on developing baseline estimations of GHG emissions from plant-pot production systems and their contribution to global warming potential. To date, pot size, irrigation delivery method and fertilizer application method have been evaluated in the production of common woody ornamental crops. In this study, two perennial herbaceous plants, full-sun-grown ‘Stella D'Oro' daylily (Hemerocallis × ‘Stella D'Oro' L.) and shade-grown ‘Royal Standard' hosta (Hosta × ‘Royal Standard') (Hosta plantaginea Aschers × Hosta sieboldiana N.Fujita) were grown utilizing one of three common fertilizer application methods (dibbled, incorporated or top-dressed). Plants were grown in 3.8 L (1 gal) nursery containers in a 6:1 pinebark:sand substrate with standard amendments. Gas samples were collected in situ according to standard GRACEnet protocols weekly for five months. Cumulative emissions for both CO2 and N2O were least for plant-pot systems using the dibbled fertilizer method, regardless of species. Cumulative CO2 emissions were highest for plants fertilized by incorporation, followed by those fertilized by top-dressing. No differences were observed between N2O efflux measurements for systems fertilized by either the incorporated or top-dressed methods. Results suggest that dibbling fertilizer could significantly decrease both CO2 and N2O emission. Index words: carbon dioxide, nitrous oxide, methane, trace gas. Species used in this study: ‘Stella D'Oro' daylily (Hemerocallis × ‘Stella D'Oro' L.); ‘Royal Standard' hosta [(Hosta × ‘Royal Standard') (Hosta plantaginea Aschers × Hosta sieboldiana N.Fujita)].

Fertilizer placement and tillage effects on phosphorus concentration in leachate from fine-textured soils

Adoption of no-tillage in agricultural watersheds has resulted in substantial reductions in sediment and particulate phosphorus (P) transport in surface runoff. No-tillage, however, may result in increased losses of dissolved P in tile-drained landscapes due to the accumulation of P in surface soil layers and prevalence of preferential flow pathways. The objective of this study was to examine the effect of fertilizer placement and tillage on P leaching in fine-textured soils following fertilizer application. Rainfall simulations (90 min; 3.8 cm rainfall depth) immediately following application of monoammonium phosphate fertilizer (75 kg P ha−1) were conducted on 9 m2 plots with pan lysimeters (0.6 m depth) in four agricultural fields located in northwestern Ohio, USA. Three fertilizer placement treatments that covered a range of soil disturbance and soil-fertilizer mixing (broadcasted, injected, and tilled) were replicated on each field. Stable water isotopes were used to separate leachate into preferential and matrix flow components. Results showed that leachate dissolved P concentration was significantly greater when fertilizer was surface broadcast on no-tilled plots (43.7 mg L−1) compared to when the fertilizer was either injected (14.9 mg L−1) or tilled (11.0 mg L−1) into the soil. Event water comprised between 6 and 46% (mean = 22%) of lysimeter leachate and did not vary among treatments. Similar event water contributions among treatments suggest that the disruption of the macropore network was not likely the main mechanism responsible for decreased P concentration in leachate, but rather increased soil-fertilizer contact and decreased interaction between the highly soluble fertilizer and ponded surface water were likely responsible for decreased P concentrations observed for the injected and tilled treatments compared to the broadcasted treatment. Findings indicate that subsurface injection of fertilizer has the potential to limit dissolved P leaching compared to surface broadcast applications and also minimize soil disturbance relative to tillage; thus, it should be considered a promising conservation practice to help meet water quality goals in tile-drained landscapes.

Effects of Fertilizer Placement and Nitrogen Forms on Soil Nitrogen Diffusion and Migration of Red-Yellow Soil in China

A better understanding of nitrogen (N) diffusion and transformation in soils could reveal the capacity of the biological inorganic N and improve the efficiency of N fertilizers. A field micro-plot experiment was carried out to study the effects of fertilization methods (mixed uniformly with 12 cm top soil, placed in holes at a 12-cm depth, or placed in furrows at a 12-cm depth) and forms of N fertilizers (urea and ammonium phosphate) on the dynamics of soil N’s vertical diffusion and horizontal migration in red-yellow soil. The soil inorganic N ( NH4+-N and NH3--N) content following point deep placement was greater than that from mixed or furrow applications. Under point placement, the migration of soil inorganic N in urea and ammonium phosphate treatments occurred in the 6 - 15 cm layer at a horizontal distance of 0 - 9 cm. However, the nutrient preservation capability of the soil receiving ammonium phosphate was greater than that receiving urea under point deep placement. Thus, point deep placement had a tendency to increase the inorganic N in the soil and reduce inorganic N loss, which probably occurred due to the reduced soil volume with which the N fertilizer was mixed. According to crop growth and fertilizer requirements, the optimized fertilizer placement and N species resulted in a continuously high nutrient supply to crops for 90 d. However, the effects of point deep placement on increasing the N-use efficiency and reducing N loss have to be evaluated under natural field conditions.

Effects of Fertilizer Placement on Trace Gas Emissions from Nursery Container Production

Increased trace gas emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are widely believed to be a primary cause of global warming. Agriculture is a large contributor to these emissions; however, its role in climate change is unique in that it can act as a source of trace gas emissions or it can act as a major sink. Furthermore, agriculture can significantly reduce emissions through changes in production management practices. Much of the research on agriculture’s role in mitigation of greenhouse gas (GHG) emissions has been conducted in row crops and pastures as well as forestry and animal production systems with little focus on contributions from specialty crop industries such as horticulture. Our objective was to determine efflux patterns of CO2, CH4, and N2O associated with three different fertilization methods (dibble, incorporated, and topdressed) commonly used in nursery container production. Weekly measurements indicated that CO2 fluxes were slightly lower when fertilizer was dibbled compared with the other two methods. Nitrous oxide fluxes were consistently highest when fertilizer was incorporated. Methane flux was generally low with few differences among treatments. Results from this study begin to provide data that can be used to implement mitigation strategies in container plant production, which will help growers adapt to possible emission regulations and benefit from future GHG mitigation or offset programs.

Fertilization Rate and Placement Effects on Areca Palms Transplanted from Containers or a Field Nursery

Areca palms (Dypsis lutescens [(H. Wendl.) Beentje and J. Dransf.]) were transplanted from containers or a field nursery and were treated with fertilizer placed at the bottom of the planting hole, incorporated into the backfill, or on the surface of the root ball to determine the effects of fertilizer placement at planting on palm growth and quality. Fertilizer was applied at 0, 250 g (20 g N), or 500 g (40 g N) per tree for each placement method to determine fertilization rate effects. Areca palms transplanted from containers grew best when fertilizer was incorporated into the backfill, but any fertilizer placement or rate was better than no fertilizer. When areca palms were transplanted from a field nursery, there was no consistently best fertilizer placement method. However, fertilized plants grew better and had less severe nitrogen and potassium deficiency symptoms than unfertilized palms. There was no benefit to higher fertilization rate for either container- or field-grown areca palms.

施肥位置が不耕起播種したコムギの出芽，初期生育，収量に及ぼす影響

施肥位置が不耕起播種したコムギの出芽，初期生育，収量に及ぼす影響

Effects of Mulch Type and Fertilizer Placement on Weed Growth and Soil pH and Nutrient Content

Four different organic mulches were applied to 1-m2 plots of Margate fine sand soil that were irrigated three times per week. A 8N–0.9P–10K–4Mg controlled-release fertilizer was applied above or below these mulches to determine the effects of fertilizer placement on weed growth and soil pH, nitrate–nitrogen, ammonium–nitrogen, potassium (K), and magnesium (Mg) concentrations. Unfertilized plots were used to determine mulch effects on soil pH and nutrient content. Fertilizer placement generally had no effect on any of these soil fertility parameters nor did it affect weed numbers. Cypress mulch increased soil K concentrations, and pine bark and eucalyptus mulch increased soil Mg over that of unmulched plots when no fertilizer was applied. The presence of any mulch type greatly reduced weed numbers over that of unmulched plots.

Placement of nitrogen, phosphorus and potassium fertilizers by drilling in spring barley grown for malt without use of pesticides

The increasing consumer demand for food products that are produced without the use of pesticides are reflected in action plans to reduce the use of pesticides in agriculture. Most of the barley (Hordeum vulgare L.) produced is used for pig feed but some is used for malting – the primary step in the production of beer. The effects of fertilizer application method, type and rate on yield and grain quality were investigated in a malting barley crop without the use of pesticides. Twelve treatments where single and multiple nutrient fertilizers were either broadcast or placed in bands by drilling, were compared in a field experiment at two sites in Denmark during 1993–96. Weeds were controlled mechanically in all treatments, and chemical control of foliar fungal diseases and insects was only carried out in two treatments. The placement of a compound NPK-fertilizer increased the grain yield and the quality parameters grain size and grading when weeds are controlled mechanically by harrowing. The effect of fertilizer placement on grain yield and quality decreased in the order NPK > NP > N>P. Herbicide-free growing of malting barley may be possible using fertilizer placement, but the use of chemical control of foliar fungal diseases and insects may be critical when pests exceed certain thresholds as they significantly reduce grain yield, grain size and grading. The aim of growing malting barley satisfactorily without the use of pesticides was only partly met.

Effects of fertilizer placement on solute leaching under ridge tillage and no tillage

Elevated nitrate concentrations in ground water can be a problem in agricultural areas, especially where soils are sandy. Tillage operations, such as ridge tillage (RT) and no tillage (NT) can reduce runoff and erosion but leaching of soluble nutrients could adversely impact groundwater. In a 2-year study, Br was used to trace the effects of fertilizer placement on solute movement under corn ( Zea mays L.) in RT and NT systems on a Monmouth fine sandy loam (Typic Hapludult) in Maryland. Treatments included 120 kg ha −1 of Br − or NO 3 −-N applied in a narrow band near the ridge top (RT-RA) or in the furrow (RT-FA) with ridge tillage, or in the inter-row with NT. Two-dimensional arrays of tensiometers and suction lysimeters were used to follow the movement of water and solutes during and after the corn-growing season. Tillage and fertilizer placement did not significantly affect N uptake when averaged across years. A pronounced argillic horizon beginning at 60 cm depth caused lateral movement of Br. It appears that Br leaching in RT-RA increased slightly due to the crop canopy funneling rain towards the ridge top. Therefore, when fertilizer is applied near the row, rain occurring after full corn canopy may cause greater solute leaching in RT-RA compared to other treatments. Rain during the beginning of the growing season or after harvest caused less leaching in RT-RA. Corn yield could be maximized and N leaching minimized by applying fertilizer to the upper portion of the ridge in RT.

Fertilizer Placement and Herbicide Rate Affect Weed Control and Crop Growth in Containers

Abstract Three experiments were conducted in Oregon and Mississippi to evaluate the effect of fertilizer placement and rate of herbicide application on weed control and crop growth. In Expt. 1, Osmocote 18N–2.6P–10.0K (18–6–12) controlled release fertilizer (CRF) was applied at 12 g (0.4 oz) per container (#1) either topdressed, incorporated, or dibbled (placed under the liner prior to potting); and OH2 (pendimethalin + oxyfluorfen) was applied at 0, 28, 56, or 112 kg/ha (0, 25, 50, or 100 lbs/A). Containers were overseeded with common groundsel (Senecio vulgaris). In Expt. 2, Osmocote 17N–3.0P–10.1K (17–7–12) CRF was applied at 18 g (0.6 oz) per container using the same placement methods as Expt. 1; and Rout (oryzalin + oxyfluorfen) was applied at 0, 28, 56, or 112 kg/ha (0, 25, 50, or 100 lbs/A). A hand-weeded check was also included, and containers were overseeded with prostrate spurge (Chamaesyce prostrata). In Expt. 3, containers were fertilized with either 12 g (0.4 oz) of Apex 20N–4.3P–8.4K (20–10–10) CRF or 14 g (0.5 oz) of Apex 17N–2.2P–9.2K (17–5–11) CRF using similar fertilizer placement methods; and Snapshot 2.5TG (isoxaben + trifluralin) was applied at 0, 84, or 168 kg/ha (0, 75, or 150 lb/A). Containers were overseeded with creeping woodsorrel (Oxalis corniculata). Weed control improved with increasing herbicide rate. Across the three experiments, dibbling CRFs with no herbicide resulted in 85 to 97% weed control, while topdressing resulted in 19 to 85% and incorporating resulted in 55 to 88% control. With herbicides, dibbling fertilizer resulted in 89 to 99% weed control while topdressing resulted in 82 to 90% and incorporating 81 to 98%. Dibbling fertilizer resulted in greater shoot growth (growth index) of azalea (Rhododendron ‘Stewartsonian’), holly (Ilex crenata ‘Compacta’), lavender (Lavandula × intermedia ‘Grosso’), and wintercreeper euonymus (Euonymus fortunei ‘Emerald Gaiety’). In Expt. 3, incorporating CRFs resulted in higher root ratings than dibbling in lavender and euonymus. Though measurable differences in root and shoot growth were observed in all experiments, differences were economically unimportant.

Effect of Fertilizer Placement on Prostrate Spurge Growth in Container Production

Abstract Three experiments were conducted to evaluate the effect of fertilizer placement on prostrate spurge growth (Chamaesyce prostrata) in container production. In experiment one, Polyon 17N–2.TP–9.2K (17–5–11) was topdressed or dibbled at 45 g (1.6 oz) or 90 g (3.2 oz) per 11.3 liter (#3) container and either 90 g (3.2 oz) or 180 g (6.3 oz) per 26.3 liter (#7) container. In experiments two and three, 180 g (6.3 oz) of Polyon 17N–2.1P–9.2K (17–5–11) was topdressed or dibbled per 26.3 liter (#7) container. In all experiments 20 prostrate spurge seed were applied to the container surface 30 days after potting. In all experiments, weed count and weight were less in dibbled containers compared to topdressed. Across all experiments, weed shoot weights at or beyond 90 days after potting were from 31 to 888% greater in topdressed containers, compared to dibbled containers. Overall, dibbling fertilizer greatly reduced weed growth while producing no visible difference in ornamental plant growth.

Effect of fertilizer placement on nitrogen loss from sugarcane in tropical Queensland

This paper reports on the fate of nitrogen (N) in a first ratoon sugarcane (Saccharum officinarum L.) crop in the wet tropics of Queensland when urea was either surface applied or drilled into the soil 3–4 days after harvesting the plant cane. Ammonia volatilization was measured with a micrometeorological method, and fertilizer N recovery in plants and soil, to a depth of 140 cm, was determined by mass balance in macroplots with 15N labelled urea 166 and 334 days after fertilizer application. The bulk of the fertilizer and soil N uptake by the sugarcane occurred between fertilizing and the first sampling on day 166. Nitrogen use efficiency measured as the recovery of labelled N in the plant was very low. At the time of the final sampling (day 334), the efficiencies for the surface and subsurface treatments were 18.9% and 28.8%, respectively. The tops, leaves, stalks and roots in the subsurface treatment contained significantly more fertilizer N than the corresponding parts in the surface treatment. The total recoveries of fertilizer N for the plant-trash-soil system on day 334 indicate significant losses of N in both treatments (59.1% and 45.6% of the applied N in the surface and subsurface treatments, respectively). Drilling the urea into the soil instead of applying it to the trash surface reduced ammonia loss from 37.3% to 5.5% of the applied N. Subtracting the data for ammonia loss from total loss suggests that losses by leaching and denitrification combined increased from 21.8% and 40.1% of the applied N as a result of the change in method of application. While the treatment resulted in increased denitrification and/or leaching loss, total N loss was reduced from 59.1% to 45.6%, (a saving of 13.5% of the applied N), which resulted in an extra 9.9%of the applied N being assimilated by the crop.

Tillage and Fertilizer Placement Effects on Staked Tomatoes Were Inconsistent

This study compared conventional tillage (CT), strip tillage (ST), and no tillage (NT) cultures for effects on tomato (Lycopersicon esculentum) fruit production. Within each tillage system, fertilization treatments were 60 lb/acre (67.2 kg·ha-1) of nitrogen (N) applied as potassium nitrate in four ways: a 2-ft-wide (0.6 m) strip over the row before transplanting, a 4-ft-wide (1.2-m) strip over the row before transplanting, N banded 6 inches (0.15 m) to the side and 4 inches (0.10 m) below the plant after transplanting, or applied through the drip irrigation system. A treatment of no fertilizer was included in the 1996 study but was discontinued in 1998 and 1999 because yields were low and this would not be a recommended practice in Tennessee. Tillage treatments had no effect on early small, medium, or large tomato yields. In 2 of the 3 years, either ST or CT treatments resulted in the highest total yields. Highest early yields were often produced by applying N in either 2-ft or 4-ft, strips over the row before transplanting. Highest late-season yields were obtained from plants receiving N applied as a band beside the row after transplanting. Results suggest that tomato yield under minimal tillage (ST or NT) was at least equivalent to CT in most years. When the economic benefits of minimal tillage are considered, these results imply that minimal tillage cultural practices are advantageous in tomato production.

Planting Date and Phosphorus Fertilizer Placement Effects on Winter Wheat

Two banding methods of applying P to winter wheat (Triticum aestivum L.), seed and knife (dual placement), have generally performed similarly when averaged over years and locations. However, performance can vary considerably from year to year, or even between locations. This study was conducted to determine the effect of optimal and delayed date of wheat planting on the performance of seed‐applied and knifed P on grain yield, P uptake, and yield components. Four rates of P (0, 11.2, 22.4, and 33.6 kg P ha−1) were seed‐ and knife‐applied on a Sharpsburg soil (fine, smectitic, mesic Typic Argiudoll) and Crete soil (fine, smectitic, mesic Pachic Argiustoll) in 1986 and two Crete soils and one Wymore soil (fine, smectitic, mesic Aquertic Argiudoll) in 1987. There were two planting dates in 1986 and three in 1987. All five soils had soil P test levels of low to very low (Bray and Kurtz P1 of 5 to 7 mg kg−1). While seed and knife application performed similarly with an optimum planting date, seed application was a superior P application method in terms of grain yield and P uptake when planting was delayed. The primary reason for the superiority of seed P application was its ability to stimulate tillering and head formation at the later planting dates. The difference in performance between the two methods of P application was probably related to quicker root access to the fertilizer P in the fall soon after planting. Root access to fertilizer P in the fall influences the number of tillers developed, which determines head number at harvest and final grain yield. Results of this research suggest that, when wheat planting date is delayed, fertilizer P should be applied with the seed for maximum effectiveness.

Fertilizer Placement Affects Jointed Goatgrass (Aegilops cylindrica) Competition In Winter Wheat (Triticum aestivum)

A 3-yr study was conducted in eastern Wyoming from 1995 to 1997 to evaluate the effect of fertilizer placement on jointed goatgrass competitiveness with winter wheat. Fertilizer placement methods consisted of applying 45 kg/ha of nitrogen (50% as urea and 50% as ammonium nitrate) in a deep band 5 cm below and 2.5 cm to the side of the wheat row, broadcasting on the soil surface, or injecting fertilizer by spoke wheel 10 cm deep and 5 cm to the side of the wheat row. Neither fertilizer placement nor jointed goatgrass presence affected winter wheat stand. Wheat yield reductions from jointed goatgrass competition were 7 and 10% higher with the broadcast than deep-band or spoke-wheel injection methods, respectively. Wheat spikes/plant, seeds/spike, 200-seed weight, and plant height were not influenced by fertilizer placement; however, the presence of 35 jointed goatgrass plants/m2reduced spikes/plant 21%, seeds/spike 12%, and 200-seed weight 6%. Jointed goatgrass populations were not influenced by fertilizer placement method; however, the number of spikes/plant was reduced 8 and 10%, joints/spike 3%, and biomass 15 and 21% by deep band or spoke wheel fertilizer placement.

Nitrogen uptake and partitioning under alternate- and every-furrow irrigation

Alternate-furrow irrigation, combined with fertilizer placement in the non-irrigated furrow, has the potential to reduce fertilizer leaching in irrigated corn (Zea mays L.). The potential also exists, however, for reduced N uptake under alternate-furrow irrigation. This study examined the effects of fertilizer placement and irrigation treatment on N uptake, roota→shoot→root circulation, and partitioning between reproductive and vegetative tissues. Rainfall was above average in both years of the study, especially during May and June, so that root growth beneath the non-irrigated furrow was equal to root production beneath the irrigated furrow. Under those conditions, soil NO3 concentration in the fertilized furrow during late-vegetative and reproductive growth was greater in the alternate-furrow compared with the every-furrow treatment, resulting in increased fertilizer N uptake during reproductive growth and increased N partitioning to reproductive tissues under alternate-furrow irrigation. About 80% of the fertilizer N found in roots had first been translocated to the shoot and then returned via the phloem to the root system. Nitrogen cycling from root to shoot to root was not affected by irrigation treatment. Alternate-furrow irrigation successfully increased N uptake and reduced the potential for NO3leaching when environmental conditions allowed adequate root development in the non-irrigated furrow, and when the growing season was long enough to allow the crop to reach physiological maturity.

No-tillage seeding: science and practice

The why and what of no tillage the nature of risk in no tillage slot shape and openers the role of slot cover drilling into dry soils drilling into wet soils seed metering and placement fertilizer placement effects residue handling by openers, drills and planters pasture renewal and renovation no-tillage drill and planter design managing a no-tillage seeding system techniques and procedures for developments.