Corn planting date: Understanding plant growth and yield response

2009 ◽  
Author(s):  
Lori J. Abendroth ◽  
Anthony J. W. Myers ◽  
Roger W. Elmore
Author(s):  
Sushil Kumar ◽  
Mukesh Jain ◽  
Vijaya Rani ◽  
Vinod Kumar ◽  
Anil Kumar ◽  
...  

1994 ◽  
Vol 34 (5) ◽  
pp. 681 ◽  
Author(s):  
NA Maier ◽  
G Barth ◽  
M Bennell

The effect of annual applications of nitrogen (N), potassium (K) and phosphorus (P) on the yield, growth and nutrient status of Ixodia daisy (Ixodia achillaeioides ssp. alata) grown on a silty loam, was investigated in field experiments conducted during 1989-91 in the Mount Lofty Ranges, South Australia. The experimental design was a randomised block with 3 replications. The N and K treatments, at annual rates up to 200 kg N/ha and 150 kg K/ha, were applied as 2 equal side-dressings. The P treatments, at rates up to 200 kg/ha, were broadcast as 1 annual application. To assess plant nutrient status we sampled the fifth leaf below the growing terminal of 50 stems in October and whole stems at harvest. As rate of applied N increased, there was a significant (P<0.05) increase in total biomass harvested, number of 3040 and 41-50 cm stems, total number of marketable stems, plant height and width. Annual N application rates of 75-110 kg/ha were required for 95% of maximum biomass yield and number of marketable stems. The application of K did not significantly (P>0.05) affect yield or plant growth. First and second order interactions between N, K and year were not significant. Plant growth and yield responses to P applied as superphosphate were inconsistent and the interaction between P and year was not significant (P>0.05). Coefficients of determination (r2) for relationships between N, K and P concentrations in the fifth leaf samples v. total biomass yield and total stem number, were in the range 0.13-0.52 for the combined 1990 and 1991 data. Based on sensitivity, reproducibility and occurrence of the Piper-Steenbjerg effect, we concluded that N, K or P concentrations in the fifth leaf sampled in October, or in whole stems at harvest, were not reliable indicators of the nutrient status of Ixodia daisy. The application of N and P did not affect the concentration of minor or micronutrients in the fifth leaf. In contrast, the application of K increased calcium (Ca), magnesium (Mg) and sulfur (S) concentrations by 14.3, 33.3 and 12.2%, respectively. For a high density planting (13,000 plants) we estimated that for N, P and K, 69.4, 6.2 and 83.2 kg/ha, respectively, are removed in marketable stems. The application of P increased extractable-P concentrations in the surface (0-15 cm) soil from 22 to 73 mg/kg. We suggest that for surface (0-15 cm) soils, extractable-P and extractable-K concentrations in the ranges 15-95 and 210-260 mg/kg, respectively, are adequate and indicate that a yield response to the application of these nutrients in fertiliser may not occur.


1993 ◽  
Vol 73 (2) ◽  
pp. 607-610 ◽  
Author(s):  
John C. Lewis ◽  
Hak-Yoon Ju

The plant growth regulators, daminozide (2500 ppm), chlormequat chloride (1500 ppm), ethephon (500 ppm), mepiquat chloride (100 ppm), and paclobutrazol (1000 ppm), were foliar applied to sprouting-year and to first fruiting-year commercial lowbush blueberry (Vaccinium angustifolium Ait.). In sprouting-year blueberry, flower bud production was increased by paclobutrazol, resulting in significantly improved bloom and yield the following year. In fruiting-year blueberry, flower bud production was significantly increased by paclobutrazol in the year of application and resulted in improved bloom and yield in the following fruiting year. The effects of the other treatments on these parameters were in most cases not significant. Daminozide showed a significant bloom response with a sprouting-year application, but this did not translate into a yield response. Key words: Vaccinium angustifolium, plant growth regulators, paclobutrazol, flower bud production


AgriPeat ◽  
2019 ◽  
Vol 18 (02) ◽  
pp. 105-112
Author(s):  
Journal Journal

ABSTRACT The purpose of this study was to determine the growth and yield of onion that were given growth regulator (PGR) and NPK fertilizer on spodosol. This study used Randomized Block Design (RBD) of factorial pattern with two factors: (1) growth regulator (0, 3, 6, and 9 mL.L-1 ), and (2) NPK fertilizer (0, 150, 300, and 450 kg ha-1). The results of this study showed tha giving of PGR increased the crop growth rate of plants aged 14-21 day after planting (1.057 g.m-2 day -1) and 21-28 day after planting (1.089 g.m-2 day-1) with the best concentration of 6 mL.L-1 water. The best NPK fertilizer dosage of 300 kg.ha-1 was able to increase plant height at 42 day after planting (46,89 cm), leaf area 21, 28 and 35 day after planting (541,22 cm2, 717,37 cm2, and 714 , 29 cm2), weight of fresh stover (75,50 g), weight of dry stover (66,19 g) and tuber weight per plot (4,520,25 g). Key words : onion, plant growth regulator (PGR), NPK, spodosol ABSTRAK Tujuan penelitian untuk mengetahui pertumbuhan dan hasil tanaman bawang merah yang diberi zat pengatur tumbuh (ZPT) dan pupuk NPK pada tanah spodosol. Penelitian ini menggunakan menggunakan Rancangan Acak Kelompok (RAK) pola faktorial dengan dua faktor, yaitu : (1) zat pengatur tumbuh (0, 3, 6, dan 9 mL.L-1 air), dan (2) pupuk NPK ( 0, 150, 300, dan 450 kg.ha-1). Hasil penelitian menunjukkan bahwa pemberian ZPT meningkatkan laju pertumbuhan tanaman umur 14-21 hst (1,057 g.m-2. hari -1) dan 21-28 hst (1,089 g.m-2. hari -1) dengan konsentrasi terbaik 6 mL.L-1 air. Dosis pupuk NPK terbaik 300 kg.ha-1 mampu meningkatkan luas daun umur 21, 28 dan 35 hst, masing-masing 541,22 cm2, 717,37 cm2, dan 714,29 cm2, bobot brangkasan segar (75,50 g), bobot brangkasan kering (66,19 g) dan bobot umbi per petak (4.520,25 g). kata kunci: bawang merah, zat pengatur tumbuh (ZPT), NPK, spodosol


HortScience ◽  
1995 ◽  
Vol 30 (5) ◽  
pp. 997-999 ◽  
Author(s):  
J.C. Palumbo ◽  
C.A. Sanchez

Imidacloprid is a new, chloronicotinyl insecticide currently being used to control sweetpotato whitefly [Bemisia tabaci Genn, also known as silverleaf whitefly (Bemisia argentifolii Bellows and Perring)]. Large growth and yield increases of muskmelon (Cucumis melo L.) following the use of imidacloprid have caused some to speculate that this compound may enhance growth and yield above that expected from insect control alone. Greenhouse and field studies were conducted to evaluate the growth and yield response of melons to imidacloprid in the presence and absence of whitefly pressure. In greenhouse cage studies, sweetpotato whiteflies developed very high densities of nymphs and eclosed pupal cases on plants not treated with imidacloprid, and significant increases in vegetative plant growth were inversely proportional to whitefly densities. Positive plant growth responses were absent when plants were treated with imidacloprid and insects were excluded. Results from a field study showed similar whitefly control and yield responses to imidacloprid and bifenthrin + endosulfan applications. Hence, we conclude that growth and yield response to imidacloprid is associated with control of whiteflies and the subsequent prevention of damage, rather than a compensatory physiological promotion of plant growth processes. Chemical names used: 1-[(6-chloro-3-pyridinyl)methyl]-4,5-dihydro-N-nitro-1-H-imidazol-2-amine (imidacloprid); [2 methyl(1,1′-biphenyl)-3yl)methyl 3-2-chloro-3,3,3-trifluoro-1-propenyl]-2,2-dimethylcyclopropane carboxylate (bifenthrin); 6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodiaxathiepin 3-oxide (endosulfan).


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