Phosphorus Fertilizer Placement Research Articles

The impact of the distribution method for struvite (Crystal Green) on the chemical composition of soybean and their utility in animal nutrition

One of the main factors considered in assessing the nutritional value of feed is its chemical composition, which can be modified by fertilization. Faced with reducing P resources, alternative sources of this element are being sought. Phosphorus is an essential nutrient in soybean cultivation. The aim of the study was to use an alternative source of phosphorus fertilizer and compare its impact on the chemical composition of soybean seeds with that of a traditional fertilizer (Super FOS DAR). The study investigated a range of factors in animal nutrition as well as the basic content of macro- and microelements. A pot experiment with the Abelina soybean variety was conducted at the Experimental Station of the Wroclaw University of Environmental and Life Sciences. The experiment considered two factors against the control: phosphorus fertilizer placement (band, broadcast) and different phosphorus fertilization (Super FOS DAR, Crystal Green). Use of struvite (Crystal Green)) caused positive changes in selected amino acids content and in the nutritional value of protein in soybean seeds; this can enhance the value of soybean seeds as well as increase certain macroelements and microelements. Phosphorus fertilizer significantly increased the content of lysine, leucine, valine, phenyloalanine and tyrosine. Band fertilization with struvite caused a significant increase in amino acids (lysine, leucine, valine, phenyloalanine and tyrosine) as well as in the nutritional value of protein (as measured by the essential amino acid index, protein efficiency ratio and biological value of the protein). Favorable changes under the influence of the application of struvite were recorded in the content of calcium, as well as phosphorus, iron, and manganese. The value of the struvite in the case of its use as phosphorus fertilizer is promising; however, it needs further study.

Deep phosphorus fertilizer placement increases maize productivity by improving root-shoot coordination and photosynthetic performance

It’s well known that the development and distribution of roots could be regulated to obtain deep soil resource and enhance the grain yield by increasing the depth of fertilization, but little is known about whether increasing P fertilization depth can optimize the root distribution to delay leaf senescence, enhance photosynthetic performance and root-shoot coordination or not. We conducted a field experiment that tested the following four placement depths of P fertilization: 5 cm (P5), 10 cm (P10), 15 cm (P15), and 20 cm (P20). The experiment was designed to explore the regulatory effects of the P fertilization depth on the root growth and distribution, the photosynthetic performance, the root-shoot coordination, the yield formation, the N and P fertilizer utilization of maize plants. We found that deep P placement did indeed alter the root parameters. In the 20–60 cm soil layer, both the root dry weight and length of P15 treatment were on average 23.2% higher than those of P5 treatment. The specific root length and specific root surface area of P15 treatment were 4.5% and 5.6% higher than those of P5 treatment. In addition, the P15 treatment achieved a significantly improved photosynthetic performance over the P5 treatment: The leaf area index at the R6 stage was 10.2% higher, the leaf senescence index from the R2 to the R6 stages was 31.4% lower, the photosynthetic rate at the R3 stage was 25.9% higher. The P placement depth also optimized the root-shoot coordination: The ratios of root weight to shoot weight, root surface area to leaf area, and root length to leaf area of P15 treatment were 6.7%, 13.8%, and 12.7% higher than those of P5 treatment, respectively. Finally, the root P and N uptake efficiency, the photosynthetic P-use efficiency, and the physiological P-use efficiency of P15 treatment were all significantly higher than those of P5 treatments. And together these responses had the effect of increasing the mature biomass by 12.5%, and the grain yield by 22.0%. In conclusion, increasing the P fertilization placement depth to 15 cm regulates the growth and development of the root system, which in turn improves the capability of plant to uptake and utilize N and P in the soil, delays the onset of leaf senescence, enhances its photosynthetic performance and biomass accumulation rate, and thus ultimately increases the yield.

Shoot and Root Responses of Mung Bean (Vigna radiata L.) to Phosphorus Fertilizer Placement with Different Potassium Sources

ABSTRACT Mung bean (Vigna radiata L.) is a major pulse crop in many parts of the world, but its yields are generally lower than other pulse crops due to biotic and abiotic stresses, including nutrition. An experiment was conducted to examine the effects of localized application of phosphorus (P) (32P labeled P fertilizer) and different sources of potassium (K) (KNO3, KCl, K2SO4 and KH2PO4) on shoot and root growth of mung bean, nutrient uptake and applied P and K recovery on a sandy loam Yellow Chromosol soil with low P and K status. Among the K sources highest shoot and root yield was obtained with K2SO4. Similarly, total plant P and the percentage of total P content obtained from the fertilizer (Pdff) was highest in this treatment. P application resulted in an increase in root length/soil mass, root mass density both inside and outside the band and in the percentage of roots in the fertilizer band. Each of the above parameters was numerically highest in the P+K2SO4 surface applied treatment. Root growth in the banded P resulted in better mung bean growth and nutrient uptake which was associated with stimulated root growth in the band and/or through increased uptake of P per unit root length. Co-application of K with P did not stimulate P uptake. Since co-application of P and K did not result in a synergistic response to either nutrient separation of these nutrients can be practiced.

EFFECT OF PHOSPHORUS FERTILIZER PLACEMENT ON EMERGENCE AND EARLY GROWTH OF CHICKPEA (Cicer arietinum L.)

Fertilizer in close proximity to seed can hamper emergence and early growth of seedlings. This study investigates whether phosphorus fertilizer placement with or close to seed affects emergence and early growth of chickpea (Cicer arietinum L.) and its relationship to soil texture. In pot culture studies with sandy soil, emergence and early growth were suppressed when triple superphosphate (TSP) and di-ammonium phosphate (DAP) were in contact with seed or banded 2cm directly below the seed; the effect of DAP was more detrimental than that of TSP. Placement of TSP at 5 cm directly below the seed did not hamper emergence in sandy soil although it still had a mild suppressive effect on early growth of chickpea. In clay soil, the recommended rate of TSP (100 kg TSP or 20 kg P ha- ) had little or no effect on emergence and negligible effect on subsequent seedling growth. In fields with clay loam soil, placement of the recommended rate of TSP with chickpea seeds in rows by a minimum-till planter was also found safe. In conclusion, the effect of phosphorus fertilizer placement in close proximity to chickpea seed was soil texture specific: in sandy soil the placement had deleterious effect on emergence and early growth while in clay soil there was little or no effect.

Evaluation of Long-Term Phosphorus Fertilizer Placement Effect on Soil Phosphorus and Crop Yield

Evaluation of Long-Term Phosphorus Fertilizer Placement Effect on Soil Phosphorus and Crop Yield

Phosphorus fertilizer placement and rate affect soybean root growth and nutrient uptake in soil with high fertility

O manejo do fertilizante fósforo (P) pode alterar o crescimento da raiz e da parte aérea da soja, promovendo desequilíbrios morfológicos na planta. Com o objetivo de avaliar os ajustes morfológicos da soja (Glycine max (L.)) em diferentes colocações e taxas de adubação fosfatada em solo P, foi realizado um estudo em casa de vegetação com dois objetivos principais: 1) avaliar o efeito da adubação fosfatada sobre a raiz e acúmulo de biomassa na parte aérea e as alterações associadas no comprimento das raízes; e, 2) estimar o efeito das alterações do crescimento radicular na absorção de macro e micronutrientes na planta. Os tratamentos com fertilizantes foram: (1) transmissão P na superfície do solo (BR), (2) P5x5 cm (B) aplicada na faixa (B) e (3) banda profunda P a 20 cm de profundidade (DB); usando duas taxas: (1) 60 e (2) 120 kg P2O5 ha-1 em solo com alta fertilidade. Imagens de minirhizotron e medidas de SPAD foram realizadas uma vez por semana até o florescimento. O peso seco da raiz e da parte aérea, bem como a absorção total de macro e micronutrientes foram avaliados no mesmo estágio. O aumento dos níveis de P no solo promovidos pela adubação mostra um efeito negativo no peso seco da raiz na taxa de 60 kg P2O5 ha-1 e muito pouco estímulo à alocação de biomassa nas raízes quando a taxa de P foi aumentada para 120 kg P2O5 ha -1 em tratamentos B e DB. O tratamento de controlo (sem fertilizante) mostrou um comprimento de raiz 108% maior do que o tratamento com B-60. Essas alterações também alteraram a absorção de macro e micronutrientes e afetaram o teor de clorofila nas plantas de soja. O aumento dos níveis de P no solo promovidos pela adubação mostra um efeito negativo no peso seco da raiz na taxa de 60 kg P2O5 ha-1 e muito pouco estímulo à alocação de biomassa nas raízes quando a taxa de P foi aumentada para 120 kg P2O5 ha -1 em tratamentos B e DB. O tratamento de controlo (sem fertilizante) mostrou um comprimento de raiz 108% maior do que o tratamento com B-60. Essas alterações também alteraram a absorção de macro e micronutrientes e afetaram o teor de clorofila nas plantas de soja. O aumento dos níveis de P no solo promovidos pela adubação mostra um efeito negativo no peso seco da raiz na taxa de 60 kg P2O5 ha-1 e muito pouco estímulo à alocação de biomassa nas raízes quando a taxa de P foi aumentada para 120 kg P2O5 ha -1 em tratamentos B e DB. O tratamento de controlo (sem fertilizante) mostrou um comprimento de raiz 108% maior do que o tratamento com B-60. Essas alterações também alteraram a absorção de macro e micronutrientes e afetaram o teor de clorofila nas plantas de soja.

Corn Response to Phosphorus Fertilizer Placement Differs by Yield Potential

Corn Response to Phosphorus Fertilizer Placement Differs by Yield Potential

Corn Response to Long‐Term Phosphorus Fertilizer Application Rate and Placement with Strip‐Tillage

Core Ideas Results showed a significant effect of P fertilizer rate and placement in early season whole plant P uptake, ear leaf P concentration, grain P concentration, and yield over the course of this study but particularly after multiple years of treatment application. Early P uptake in corn was consistently higher with deep band P fertilizer applications and with starter fertilizer with the planter. The long‐term evaluation of P fertilizer placement showed that deep‐band P placement only seldom resulted in higher yields. The use of starter fertilizer increased average grain yield, particularly for high‐yielding systems. Multiple years of phosphorus (P) fertilizer application may be needed before the agronomic and environmental effect of P fertilizer placement and application rate become noticeable. The objective of this study was to evaluate the long‐term effects of P placement on corn (Zea mays L.) with strip‐tillage. The study was conducted for 10 yr at two locations in Kansas in a corn and soybean (Glycine max L.) rotation from 2006 to 2015. Strip‐tillage was conducted before corn and soybean were planted without previous tillage. Phosphorus fertilizer placement and rate treatments included a control, broadcast at 20 kg P ha−1 and 39 kg P ha−1, deep‐band at 20 kg P ha−1, and 39 kg P ha−1, in a factorial combination with two starter fertilizer treatments (with and without starter fertilizer). Response parameters included V6 whole plant P uptake, ear leaf P, grain P concentration, and yield. Phosphorus fertilizer increased crop response parameters when compared to the control including yield for some years or across years at the two locations. However, corn response was similar among the P rate‐place treatments with generally higher values for the P rate of 39 kg P ha−1. The use of starter fertilizers in combination with broadcast or deep‐band P fertilizer resulted in greater P uptake, ear leaf P and grain P; however only increased yield at one location. Results from this study showed similar corn yield for deep‐band and broadcast P fertilizer under strip‐tillage and starter fertilizer increased yield for a high‐yielding, low soil test P location.

Deep Banding Increases Phosphorus Removal by Soybean Grown under No‐Tillage Production Systems

Core Ideas Deep band P is a potential strategy to reduce P losses by runoff. Deep band P improve soil fertility in subsurface in no‐till system. Greater amount of P removed with grain compared to the total P input. Phosphorus fertilizer placement can have significant agronomic and environmental implications in long‐term no‐till (NT) systems. The objective of this study was to evaluate soybean [Glycine max (L.) Merr.] response to P fertilizer placement strategies under long‐term NT management. A field study was performed near Nao‐Me‐Toque‐RS (Location 1) and Sao Sepe‐RS (Location 2), southern Brazil, during the 2014/2015 growing season. The experimental design was a randomized complete block with three replications. Triple superphosphate was applied using five strategies: (i) strip tillage with deep band (ST‐DB); (ii) strip tillage with band‐applied 5 by 5 cm (ST‐B); (iii) no‐till with broadcast (NT‐BR); (iv) no‐till with band‐applied 5 by 5 cm (NT‐B); (v) and no‐till with surface band (NT‐SB). Plant height, dry weight, and P uptake were evaluated at 20, 40, 60, and 80 d after emergence (DAE) as well as P removed and grain yield at harvest. The ST‐B application promoted greater plant height, dry weight, and P uptake at 80 DAE. However, ST‐DB showed the greatest P removal compared to other treatments. Also, greater yields were obtained for ST‐DB and NT‐BR. Soil sampling after harvest showed that ST‐DB increased soil test P levels by 19 and 11% at the 15‐ to 25‐cm layer for Locations 1 and 2, respectively. While NT‐BR increased soil test P by 43 and 36% at the 0‐ to 5‐cm layer for Locations 1 and 2, respectively. Deep band P fertilizer placement maintained or increased soybean yield and P use under long‐term NT in tropical soils.

Long term impact of no-till on soil properties and crop productivity on the Canadian prairies

Meeting the needs of an increasing population requires protection of our arable land base and improvements in productivity. The study compared soil quality characteristics and crop yield to nitrogen (N) fertilizer in two adjacent fields; one field managed with no-till for 31 years while the other for 9 years. In 2003, the two fields along with native prairie were sampled for soil quality parameters across two landscape positions. A small plot study involving five rates of urea N (0, 30, 60 90 and 120 kg N ha −1) and two phosphorus fertilizer placement methods (seed-placed vs side-banded) was conducted on the two adjacent fields for the period 2002–2009. The rates of N were superimposed on the same plots each year whereas wheat and canola were normally grown in alternate years. An N balance was conducted after 8 years to account for inputs and outputs of N. Soil bulk density values were 0.98 g cm −3 for native prairie and 1.46 for LTNT and STNT in the 0–15 cm soil layer. The native prairie had 48.2 t ha −1of SOC vs 44.4 and 36.7 for LTNT and STNT, respectively, in the 0–15 cm soil layer and no detectable differences for the 15–30 cm soil layer in 2003. Potentially mineralizable N using the Hot KCl digestion in the 0–15 cm soil layer was 60 kg ha −1 of ammonium nitrogen for native prairie and 30 and 22 kg ha −1 for LTNT and STNT, respectively. For amino sugar-N, native prairie had 558 kg ha −1 vs 462 and 370 kg ha −1 for the LTNT and STNT, respectively. This indicates a positive relationship between SOC levels measured and potentially mineralizable N reflecting differences in land management. Phosphorus fertilizer placed in the side-band with N yielded 3.5% more than seed-placed phosphorus in spring wheat and no difference in canola. Grain yields were 14% and 16% more for LTNT than STNT in spring wheat and canola, respectively. Maximum grain N removal averaged in wheat was 87 kg ha −1 for LTNT and 74 kg ha −1 for STNT and 71 and 65.4 kg ha −1 in canola, respectively. A positive N balance was obtained provided that 60 kg ha −1 of N was applied every year and no accumulation of nitrate-N was noted even with rates that exceeded N removal in the grain. This supports the view that no-till combined with continuous cropping and proper fertility represents a path to sustaining the global soil resource.

Evaluation of Nitrogen and Phosphorus Fertilizer Placement with Strip Tillage for Irrigated Pacific Northwest Corn Production

Nutrient placement options with strip tillage (ST) can potentially improve plant nutrient utilization and increase crop yield compared to conventional fertilizer placement practices under conventional tillage (CT). The effects of tillage practice and N and P placement on grain yield, biomass yield (whole plant, grain + cobs + stover), and N and P uptake of field corn (Zea mays L.) were assessed on four sites during 2007 and 2009 at the USDA-ARS Northwest Irrigation & Soils Research Laboratory at Kimberly, ID. During each year, two locations (eroded and not eroded from furrow irrigation) were utilized as study locations. Band placement (15 to 20 cm below the soil surface) of fertilizer with ST increased corn grain yield by 12.5 (689 kg/ha) and 25.9% (1,626 kg/ha) on the eroded locations compared to broadcast N and P and 5 × 5-cm N under CT in 2007 and 2009, respectively. These increased yields also resulted in greater removal of N and P. Reduced tillage costs of ST with associated band placement of N and P could increase the economic productivity of many acres of land in the Pacific Northwest.

Yield and Economic Responses to Phosphorus Fertilizer Placement in Dual‐Use and Grain‐Only Wheat Production Systems

Wheat (Triticum aestivum L.) production in the southern Great Plains is a unique enterprise that provides both high‐quality forage and a grain crop within the same growing season. However, information on fertility management programs to maximize forage and beef production in a dual‐use wheat production system is lacking. A 3‐yr, field‐scale production study was initiated on a Tillman clay loam near Vernon, TX, in 1999 to (i) determine the influence of P fertilizer and P fertilizer placement on forage, beef, and grain production from dual‐use wheat, and (ii) compare economic costs and returns of dual‐use and grain‐only wheat production systems. Varying numbers of stocker cattle (Bos spp.) were placed in each pasture based on forage availability. Beef‐to‐forage allowance among pastures was kept relatively constant by adjusting cattle numbers monthly. Applying 20 kg P ha−1 yr−1 increased soil test P in the upper 15 cm two‐ to threefold, forage production 18 to 54%, and animal gains ha−1 27 to 29% compared with no P. With respect to forage and subsequent beef production, surface‐applied P was generally equal to or better than injected P. Average return between the graze‐plus‐grain and graze‐out systems was significant (P < 0.0001) but not among fertilizer treatments (P = 0.26), although surface‐applied P resulted in numerically higher returns each year. There was no significant system × fertilizer treatment interaction. However, during the study period, the graze‐plus‐grain system was clearly superior to the graze‐out system in generating higher net returns ($94 vs. $29 ha−1).

Phosphorus Runoff from Sugarbeet Production Systems as Affected by Tillage and Phosphorus Fertilizer Placement

Sugarbeet production systems are potentially vulnerable to significant phosphorus (P) losses. Production practices that may reduce P loss risk are being considered. However, the potential benefits of these practices are not well estab­ lished. A rainfall simulation study was conducted to deter­ mine P losses from various tillage (moldboard, chisel, and deep chisel) and phosphorus fertilizer placement (broad­ cast and band). Sugarbeet (Beta vulgaris L.) corn (Zea mays L.), and soybean (Glycine max L.) rotations were studied. A rainfall simulator was used to create runoff ** '-<

Effects of P Fertilizer Placement and Temperature on Root Hair Formation, Shoot Growth and P Content of Barley Grown on Soils with Varying P Status

Seed placed phosphorus (P) is hypothesized to increase P utilization in plants, particularly in cool climate. A greenhouse experiment was conducted to evaluate the effects of seed placed P at two temperature regimes (7 °C night/9 °C day or 13 °C night/15 °C day) within the first weeks of the growing season on root hair formation, shoot growth and P content of spring barley (Hordeum vulgare L.). Three soils (loam, clay loam and sandy silt texture) were used, each with two levels of plant available P (low and high P-AL). In half of the pots, all P (10 mg P kg−1 soil) was applied 5 cm below the seed. In the other pots, half of the P was applied in the same way, and half was given together with the seeds as starter fertilizer. When plants reached growth stage (GS) 21, two replicates were harvested and temperature adjusted to 15 °C night/17 °C day for the remaining three replicates, which were harvested at GS 49. Phosphorus fertilizer placement did not interact with temperature, soil P level or soil type, and it had also only few and slight effects on shoot dry matter (DM) and P content. The lower temperature regime delayed growth rate by nine days until GS 21, but shoot DM and P content was not significantly affected. At GS 49, both shoot DM and P content increased by 20% from low to high temperature. The soil P level influenced shoot P content to a high degree, with an increase by 190% at high P-AL compared to low P-AL at GS 21, and by 170% at GS 49. The length of root hairs within treatments was very variable, and no significant differences were found between the treatments. So the ability to adapt morphologically to suboptimal conditions was not great enough to avoid reduced growth because of P deficiency. Placing some P together with the seeds could either inhibit limited P uptake at suboptimal growth conditions in this trial. Seed placement of P is recommended in Norway, especially on silty soils. However, the results from this study support what are observed in field, that the positive effects of seed placed fertilizer are variable. The subject indeed needs further investigation before the effect of seed placed P are fully understood.

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.

Dry bean production with various tillage and residue management systems

Limited information is available on the influence of high surface residue tillag systems and the interaction of weed control methods, cultivar maturity, and phosphorus fertilizer placement on yield parameters of dry bean ( Phaseolus vulgaris L.) A 3-year field study was conducted on a Fargo clay (fine, frigid, montmorillonitic Vertic Haplaquoll) to evaluate the influence of surface or deep band placed phosphorus fertilizer, tillage systems (PLOW, SWEEP, STRIP, NOTILL) and weed control methods on harvest plant populations, seed yield and seed weight of ‘Upland’ (early maturity) and ‘C-20’ (late maturity) dry bean cultivars. Yield variables were influenced by cultivar planted and climatic conditions. Zinc deficient plants and decreased yield were observed with the ‘C-20’ cultivar when grown on PLOW system plots where phosphorus fertilizer was surface applied. Zinc deficient plants were not present when the phosphorus fertilizer was deep banded or none was applied. No zinc deficient plants were observed on NOTILL, STRIP and SWEEP system plots. Both cultivars matured 7 to 10 days earlier with NOTILL, STRIP and SWEEP systems when compared with the PLOW system. Dry bean yields were reduced 180 to 310 kg ha −1 by cultivation for weed control. Little difference in yields occurred among tillage systems when climatic conditions were normal. During a cool wet season, seed yields on PLOW system plots were 150 to 400 kg ha −1 higher than on plots of systems with surface residue. Seed weight, although lower on the late maturity cultivar, was not greatly changed by tillage or weed control method. Results from this study indicate that dry beans can be successfully grown with small grain surface residue systems in northern climatic areas where growing degree days exceed 1200 and growing season precipitation does not exceed 400 mm. Further, deep band placement of phosphorus fertilizer is essential in dry bean rotations to eliminate potential zinc deficiency on soils low in zinc. Switching to a high residue management system may require a special cultivator design to eliminate yield loss due to pruning of shallow roots present with high surface residue.

Phosphorus Fertilizer Placement and Tillage in a Wheat‐Fallow Cropping Sequence

AbstractSince water and wind erosion are serious problems during fallow in most western winter wheat (Triticum aestivum L.) growing areas and available soil P is often low, field studies were conducted at three locations in western Nebraska on a Keith silt loam (fine‐silty, mixed, mesic, Aridic Argiustoll). These studies compared the performance of broadcast, knife and seed placement of fertilizer P with and without a residue treatment of 13.5 Mg ha−1 in a plow, no‐till, and stubble mulch tillage system. Plowing generally tended towards the highest and no‐till the lowest grain yield and P uptake. Delayed maturity resulting from abnormally cool spring temperatures was believed to be a contributing factor to lower yields in no‐till. Without applied residue, grain yields were increased by P placement methods in the order of seed = knife &gt; broadcast similar to other reported research. When residue was applied, knife placement was less effective and broadcast more effective compared to seed placement at the low P rate (8.4 kg ha−1). At the high P rate (16.8 kg ha−1) seed placement produced the highest yield of all treatments. Seed placement showed higher P uptake in no‐till than other tillage treatments at one location while broadcast P resulted in higher P uptake with plowing than with stubble mulch or no‐till at another location. The colder soil temperatures associated with surface residues apparently favored seed placement of P. There was a trend for grain yield and P uptake to be lower when P was knifed in the presence of surface residues.

Effect of Phosphorus Fertilizer Placement on Root and Shoot Growth of Wetland Rice

Effect of Phosphorus Fertilizer Placement on Root and Shoot Growth of Wetland Rice

Influence of Phosphorus Fertilizer Placement on Two Nebraska Sub-Irrigated Meadows

Influence of Phosphorus Fertilizer Placement on Two Nebraska Sub-Irrigated Meadows