ASSESSING NITROGEN NUTRITIONAL STATUS, BIOMASS AND YIELD OF COTTON WITH NDVI, SPAD AND PETIOLE SAP NITRATE CONCENTRATION

SUMMARYCanopy normalized difference vegetation index (NDVI), soil plant analysis development (SPAD) reading and petiole sap NO3−‒N concentration are increasingly used as quick and non-destructive methods to monitor plant N nutrition and growth status and predict yield of crops. However, little information is available on the comparisons of these three methods in assessing N nutrition, growth and yield for cotton (Gossypium hirsutum L.). Four N rates (0, 34, 67 and 101 kg N ha−1) under two cover conditions [no cover crop and hairy vetch (Vicia villosa) crop] in a 33-year long-term field trial were used to evaluate how canopy NDVI, SPAD reading (related to chlorophyll content) and petiole sap NO3−‒N concentration (conventional method) are able to assess N nutrition and plant biomass and predict yield for cotton. Canopy NDVI and SPAD readings responded less sensitively to N rates than petiole sap NO3−‒N. The responses of NDVI and SPAD reading to N rates were generally reduced due to the winter cover crop with hairy vetch. Significant and positive correlations existed mostly among NDVI, SPAD reading, and petiole sap NO3−‒N concentration. Canopy NDVI during mid-bloom to late bloom and SPAD reading during early bloom to late bloom were effective alternative methods for assessing cotton N nutrition status. The SPAD reading at late bloom was an effective parameter to estimate cotton biomass. The NDVI at early square and SPAD reading during early square to mid-bloom were effective for cotton yield prediction.

Download Full-text

Use of an Active Canopy Sensor Mounted on an Unmanned Aerial Vehicle to Monitor the Growth and Nitrogen Status of Winter Wheat

Remote Sensing ◽

10.3390/rs12223684 ◽

2020 ◽

Vol 12 (22) ◽

pp. 3684

Author(s):

Jie Jiang ◽

Zeyu Zhang ◽

Qiang Cao ◽

Yan Liang ◽

Brian Krienke ◽

...

Keyword(s):

Winter Wheat ◽

Dry Matter ◽

Vegetation Index ◽

Nutrition Status ◽

Growth Stages ◽

Growth Indices ◽

N Accumulation ◽

N Nutrition ◽

Red Edge ◽

Aerial Vehicle

Using remote sensing to rapidly acquire large-area crop growth information (e.g., shoot biomass, nitrogen status) is an urgent demand for modern crop production; unmanned aerial vehicle (UAV) acts as an effective monitoring platform. In order to improve the practicability and efficiency of UAV based monitoring technique, four field experiments involving different nitrogen (N) rates (0–360 kg N ha−1) and seven winter wheat (Triticum aestivum L.) varieties were conducted at different eco-sites (Sihong, Rugao, and Xinghua) during 2015–2019. A multispectral active canopy sensor (RapidSCAN CS-45; Holland Scientific Inc., Lincoln, NE, USA) mounted on a multirotor UAV platform was used to collect the canopy spectral reflectance data of winter wheat at key growth stages, three growth parameters (leaf area index (LAI), leaf dry matter (LDM), plant dry matter (PDM)) and three N indicators (leaf N accumulation (LNA), plant N accumulation (PNA) and N nutrition index (NNI)) were measured synchronously. The quantitative linear relationships between spectral data and six growth indices were systematically analyzed. For monitoring growth and N nutrition status at Feekes stages 6.0–10.0, 10.3–11.1 or entire growth stages, red edge ratio vegetation index (RERVI), red edge chlorophyll index (CIRE) and difference vegetation index (DVI) performed the best among the red edge band-based and red-based vegetation indices, respectively. Across all growth stages, DVI was highly correlated with LAI (R2 = 0.78), LDM (R2 = 0.61), PDM (R2 = 0.63), LNA (R2 = 0.65) and PNA (R2 = 0.73), whereas the relationships between RERVI (R2 = 0.62), CIRE (R2 = 0.62) and NNI had high coefficients of determination. The developed models performed better in monitoring growth indices and N status at Feekes stages 10.3–11.1 than Feekes stages 6.0–10.0. To sum it up, the UAV-mounted active sensor system is able to rapidly monitor the growth and N nutrition status of winter wheat and can be deployed for UAV-based remote-sensing of crops.

Download Full-text

Weed Control and Sweet Corn (Zea maysvar.rugosa) Response in a No-till System with Cover Crops

Weed Science ◽

10.1017/s0043174500094005 ◽

1996 ◽

Vol 44 (2) ◽

pp. 355-361 ◽

Cited By ~ 50

Author(s):

Nilda R. Burgos ◽

Ronald E. Talbert

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Sweet Corn ◽

Weed Suppression ◽

Growth And Yield ◽

Hairy Vetch ◽

Yellow Nutsedge ◽

No Till ◽

Agricultural Experiment ◽

And Control

Studies were conducted at the Main Agricultural Experiment Station in Fayetteville and the Vegetable Substation in Kibler, Arkansas, in 1992 and 1993 on the same plots to evaluate weed suppression by winter cover crops alone or in combination with reduced herbicide rates in no-till sweet corn and to evaluate cover crop effects on growth and yield of sweet corn. Plots seeded to rye plus hairy vetch, rye, or wheat had at least 50% fewer early season weeds than hairy vetch alone or no cover crop. None of the cover crops reduced population of yellow nutsedge. Without herbicides, hairy vetch did not suppress weeds 8 wk after cover crop desiccation. Half rates of atrazine and metolachlor (1.1 + 1.1 kg ai ha−1) reduced total weed density more effectively in no cover crop than in hairy vetch. Half rates of atrazine and metolachlor controlled redroot pigweed, Palmer amaranth, and goosegrass regardless of cover crop. Full rates of atrazine and metolachlor (2.2 + 2.2 kg ai ha−1) were needed to control large crabgrass in hairy vetch. Control of yellow nutsedge in hairy vetch was marginal even with full herbicide rates. Yellow nutsedge population increased and control with herbicides declined the second year, particularly with half rates of atrazine and metolachlor. All cover crops except hairy vetch alone reduced emergence, height, and yield of sweet corn. Sweet corn yields from half rates of atrazine and metolachlor equalled the full rates regardless of cover crops.

Download Full-text

Cover Crop Biomass Harvest Influences Cotton Nitrogen Utilization and Productivity

International Journal of Agronomy ◽

10.1155/2012/420624 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12 ◽

Cited By ~ 4

Author(s):

F. Ducamp ◽

F. J. Arriaga ◽

K. S. Balkcom ◽

S. A. Prior ◽

E. van Santen ◽

...

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Animal Feed ◽

N Uptake ◽

Yield Response ◽

Cotton Production ◽

Southeastern Us ◽

N Concentration ◽

Winter Cover ◽

N Rates

There is a potential in the southeastern US to harvest winter cover crops from cotton (Gossypium hirsutumL.) fields for biofuels or animal feed use, but this could impact yields and nitrogen (N) fertilizer response. An experiment was established to examine rye (Secale cerealeL.) residue management (RM) and N rates on cotton productivity. Three RM treatments (no winter cover crop (NC), residue removed (REM) and residue retained (RET)) and four N rates for cotton were studied. Cotton population, leaf and plant N concentration, cotton biomass and N uptake at first square, and cotton biomass production between first square and cutout were higher for RET, followed by REM and NC. However, leaf N concentration at early bloom and N concentration in the cotton biomass between first square and cutout were higher for NC, followed by REM and RET. Seed cotton yield response to N interacted with year and RM, but yields were greater with RET followed by REM both years. These results indicate that a rye cover crop can be beneficial for cotton, especially during hot and dry years. Long-term studies would be required to completely understand the effect of rye residue harvest on cotton production under conservation tillage.

Download Full-text

Nitrogen and potassium nutrition of Australian waxflowers grown in siliceous sands. 2. Effect on leaf colour, vase life, and soil pH and conductance

Australian Journal of Experimental Agriculture ◽

10.1071/ea9960367 ◽

1996 ◽

Vol 36 (3) ◽

pp. 367 ◽

Cited By ~ 3

Author(s):

NA Maier ◽

GE Barth ◽

MN Bartetzko ◽

JS Cecil ◽

WL Chvyl

Keyword(s):

Soil Ph ◽

South Australia ◽

Potassium Sulfate ◽

Growth And Yield ◽

Vase Life ◽

N Nutrition ◽

Leaf Colour ◽

Soil Conductance ◽

Dark Green ◽

N Rates

The effects of nitrogen (N) and potassium (K) on leaf colour, vase life of flowering stems, and soil pH and electrical conductivity (conductance) were investigated for Australian waxflowers. Experiments were conducted on commercial plantings of Chamelaucium uncinatum cvv. Alba and Purple Pride, and a Chamelaucium hybrid (C. floriferum x C. uncinatum) known locally as Walpole wax, at 3 sites in South Australia. Nitrogen (as NH4NO3) and K (as K2SO4) were applied at rates up to 160 g N/plant and 80 g K/plant over several side dressings during the growing season. Application of N significantly (P<0.05) increased leaf colour ratings for the cv. Alba and Walpole wax. At the higher N rates leaves were dark green. Differences between years were small compared with the effect of applied N. The N x year interaction, and the effect of applied K, were not significant (P>0.05) at any site. For cv. Alba, application of N significantly increased vase life by 5 days in 1992 and 3 days in 1993. For Walpole wax, the effect of N was not consistent between years. Each year, the vase life of flowering stems from cv. Alba were consistently greater compared with stems from Walpole wax. Application of K did not significantly (P>0.05) effect vase life at any site. Annual applications of 80 or 160 g N/plant, as ammonium nitrate, significantly decreased soil pH by 0.3-1.4 units after 2-3 years, whereas application of K, as potassium sulfate, did not affect soil pH. The effect of applied N on soil conductance, although significant, was not consistent between sites. For example, at site 1, increasing the rate of applied N from 0 to 80 g N/plant increased conductance from 0.04 to 0.08 mS/cm in 1992. However, in 1993 it decreased from 0.04 to 0.02 mS/cm. The low conductance values (0.02-0.09 mS/cm) in the 0-60 cm soils, show that fertiliser salts did not accumulate over the course of the study to concentrations which adversely affect plant growth and yield. We conclude that N stress was a significant factor in the occurrence of poor leaf colour, and may be a major factor in the occurrence of defoliation during the flowering period. Optimising N nutrition improved leaf colour, vase life and, depending on the rate, did not significantly increase soil acidity or conductance after 2-3 years.

Download Full-text

Effects of nitrogen fertilizer and tridemorph on mildew, growth and yield of spring barley 1975–7

The Journal of Agricultural Science ◽

10.1017/s0021859600038557 ◽

1983 ◽

Vol 101 (3) ◽

pp. 517-546 ◽

Cited By ~ 14

Author(s):

J. F. Jenkyn ◽

M. E. Finney ◽

G. V. Dyke

Keyword(s):

Grain Size ◽

Powdery Mildew ◽

Grain Yield ◽

Spring Barley ◽

Growth And Yield ◽

Aerial Photographs ◽

Alternative Methods ◽

Yield Response ◽

Positional Variation ◽

N Rates

SUMMARYExperiments with spring barley in 1975–7 tested fungicides applied to control powdery mildew (tridemorph) or brown rust (benodanil) in factorial combination with six amounts of fertilizer N, applied either to the seed bed soon after sowing, as a later top dressing or half at each time.Powdery mildew was the principal leaf disease in all three years. It tended to be increased by increments of N and by applying the N late but much less consistently in the first two years, when soils were very dry for much of the growing period, than in 1977 when amounts of rain were much closer to the long-term mean. Tridemorph significantly increased the number of ears in 1975, mean number of grains per ear in 1976 and 1000-grain weight in all three years; it gave net increases in grain yield of 0·55, 0·68 and 0·41 t/ha, respectively, in 1975–7. Yield response to increasing amounts of applied N was greatly increased where mildew had been controlled by the use of tridemorph, and was better where the N had been divided into two dressings than where it had been applied as a single dose. In 1975 and 1977 the biggest responses to tridemorph were obtained with late N but in 1976 yield was increased most by tridemorph where the N had been applied to the seed bed.Analyses of samples taken in 1977 showed no significant effect of tridemorph sprays on concentrations of either N, P or K in the green crop. By contrast, analyses of grain samples in 1976 and 1977 showed that amounts of N in grain (mg N/grain) were affected by amounts of applied N and by tridemorph, and that there were interactions between these two factors. Concentrations of N in the grain (% D.M.) were also determined by the effects which these factors had on grain size. At small N rates tridemorph mostly increased grain size so that N concentrations were decreased by the fungicide. At large N rates increases in grain size where tridemorph had been applied were accompanied by increases in the N content of the grain (mg N/grain) so that N concentrations were either unaffected (1976) or were increased (1977) by the fungicide. With 90 kg/ha of applied N the fungicide increased the amount of N/ha removed in grain by over 21 % in each year. The apparent recoveries of N in these plots were increased from 66 to 81 % and from 87 to 105%, respectively, in the two years. Tridemorph had no significant effect on concentrations of P or K in the harvested grain but increased average amounts of these nutrients removed in the grain by 17 and 14%, respectively, in 1976 and by 14 and 7% respectively, in 1977.Examination of black and white, infra-red aerial photographs of the experiments showed that, in each year, the brightness of individual plot images was significantly correlated with grain yield.Complex designs without division into blocks are especially vulnerable to positional variation. Alternative methods of adjusting for such positional variation were compared in analyses of grain yields. The potential improvements in precision which might be achieved by the appropriate use of such analyses, and the difficulties of ensuring that unacceptable subjectivity and bias are not thereby introduced into the analyses, are discussed.

Download Full-text

Use of Pre-sidedress Nitrate Test and SPAD Meter to Evaluate Nitrogen Needs of Peppers

HortScience ◽

10.21273/hortsci.30.4.863f ◽

1995 ◽

Vol 30 (4) ◽

pp. 863F-863

Author(s):

Francis X. Mangan ◽

John Howell ◽

Stephen Herbert

Keyword(s):

Cover Crop ◽

Winter Rye ◽

Soil Nitrate ◽

Hairy Vetch ◽

Vicia Villosa ◽

Yield Increase ◽

Nitrate N ◽

Current Threshold ◽

N Rates ◽

Spad Readings

Hot cherry peppers were grown after incorporation of the following three winter cover crop regimes in Summer 1994—hairy vetch (Vicia villosa) plus winter rye (Secale cereale), hairy vetch alone, and no cover crop. For each main effect there were three N rates applied to peppers in three applications over the course of the season: 0, 85, and 170 kg·ha–1. The pepper yield was significantly higher with hairy vetch plus rye than rye alone or no cover crop. There was also no significant yield increase with the addition of N fertilizer to the peppers grown with hairy vetch. Soil nitrate–N levels taken just prior to N sidedress were significantly higher in plots that had hairy vetch plus rye compared to other treatments. There was also a significant linear relationship of the soil nitrate–N levels among the three N rates. Based on the results of this study, sidedressing peppers would be recommended when soil nitrate levels are above the 25 ppm that is the current threshold for other crops. SPAD readings were taken several times during the season. There was a high correlation of SPAD readings to pepper yield very early and very late in the season. The correlation of SPAD readings to pepper yield was poorest when taken at the time of N sidedress.

Download Full-text

No-till snap bean performance and weed response following rye and vetch cover crops

Renewable Agriculture and Food Systems ◽

10.1017/s1742170516000405 ◽

2016 ◽

Vol 32 (5) ◽

pp. 463-473 ◽

Cited By ~ 3

Author(s):

Rick A. Boydston ◽

Martin M. Williams

Keyword(s):

Cover Crops ◽

Cover Crop ◽

Crop Residues ◽

Growth And Yield ◽

Hairy Vetch ◽

Common Vetch ◽

Snap Bean ◽

Weed Biomass ◽

No Till ◽

Density And Biomass

AbstractFall-planted cover crops offer many benefits including weed suppressive residues in spring sown crops when controlled and left on the soil surface. However, vegetable growers have been slow to adopt direct-seeding (no-till) into cover crop residues. Field studies were conducted in 2009 and 2010 near Paterson, WA and Urbana, IL to evaluate mortality of rye and common vetch (WA) hairy vetch (IL) cover crops, weed density and biomass, and snap bean growth and yield following four cover crop control methods utilizing a roller–crimper. Rye had higher mortality than common and hairy vetch by roller-crimping, and carfentrazone applied after roller crimping only slightly increased vetch mortality. Heavy residues of rye and escaped vetch were difficult to plant into, often resulting in lower snap bean populations. Rye and hairy vetch residues suppressed final weed biomass, while common vetch reduced weed biomass 1 of 2 years. Escaped plants of both vetch species became a weed. Snap bean yields were inconsistent and often lower following cover crops compared with a fallow treatment. Being able to completely control cover crops and to plant, manage escaped weeds and mechanically harvest in the presence of heavy residues are challenges that deter vegetable growers from readily adopting these systems.

Download Full-text

The Influence of a Hairy Vetch (Vicia villosa) Cover Crop on Weed Control and Corn (Zea mays) Growth and Yield

Weed Technology ◽

10.1017/s0890037x00028682 ◽

1994 ◽

Vol 8 (4) ◽

pp. 777-784 ◽

Cited By ~ 23

Author(s):

William S. Curran ◽

Lynn D. Hoffman ◽

Edward L. Werner

Keyword(s):

Cover Crop ◽

Crop Management ◽

Growth And Yield ◽

Management Systems ◽

Hairy Vetch ◽

Vicia Villosa ◽

Field Corn ◽

No Till ◽

Crop Management Systems ◽

Residual Herbicide

Influences of a hairy vetch cover crop and residual herbicides were examined in field corn in 1991 and 1992. Hairy vetch was seeded in mid-August and killed the following May with tillage, mowing, or glyphosate plus 2,4-D (no-till). These cover crop management systems were compared with a no-cover treatment. Residual herbicides including atrazine plus metolachlor applied PRE at three rates and nicosulfuron plus thifensulfuron applied POST at a single rate were compared within cover crop management systems. All cover crop management systems effectively controlled hairy vetch except mowing in 1992. The corn population was reduced in mow treatments containing uncontrolled vetch. Hairy vetch mulch suppressed some weeds in the no-till treatments in 1991, but more annual grass was noted late in the season with no-till into hairy vetch than with the no-cover treatments in 1992. Residual herbicide performance was similar across cover crop management systems, except for fall panicum control which decreased in some no-till systems. Unlike soil-applied herbicides, performance of POST herbicides was unaffected by cover crop management systems.

Download Full-text