Relationship of Hyperspectral Reflectance Indices with Leaf N and P Concentration, Dry Matter Accumulation and Grain Yield of Wheat

2016 ◽  
Vol 45 (5) ◽  
pp. 773-784
Author(s):  
Ashaq Hussain ◽  
Rabi Narayan Sahoo ◽  
Dinesh Kumar ◽  
Sanatan Pradhan
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiu-Xiu Chen ◽  
Wei Zhang ◽  
Xiao-Yuan Liang ◽  
Yu-Min Liu ◽  
Shi-Jie Xu ◽  
...  

Abstract Although researchers have determined that attaining high grain yields of winter wheat depends on the spike number and the shoot biomass, a quantitative understanding of how phosphorus (P) nutrition affects spike formation, leaf expansion and photosynthesis is still lacking. A 3-year field experiment with wheat with six P application rates (0, 25, 50, 100, 200, and 400 kg P ha−1) was conducted to investigate this issue. Stem development and mortality, photosynthetic parameters, dry matter accumulation, and P concentration in whole shoots and in single tillers were studied at key growth stages for this purpose. The results indicated that spike number contributed the most to grain yield of all the yield components in a high-yielding (>8 t/ha) winter wheat system. The main stem (MS) contributed 79% to the spike number and tiller 1 (T1) contributed 21%. The 2.7 g kg−1 tiller P concentration associated with 15 mg kg−1 soil Olsen-P at anthesis stage led to the maximal rate of productive T1s (64%). The critical shoot P concentration that resulted in an adequate product of Pn and LAI was identified as 2.1 g kg−1. The thresholds of shoot P concentration that led to the maximum productive ability of T1 and optimal canopy photosynthetic capacity at anthesis were very similar. In conclusion, the thresholds of soil available P and shoot P concentration in whole plants and in single organs (individual tillers) were established for optimal spike formation, canopy photosynthetic capacity, and dry matter accumulation. These thresholds could be useful in achieving high grain yields while avoiding excessive P fertilization.


1990 ◽  
Vol 70 (1) ◽  
pp. 51-60 ◽  
Author(s):  
D. T. GEHL ◽  
L. D. BAILEY ◽  
C. A. GRANT ◽  
J. M. SADLER

A 3-yr study was conducted on three Orthic Black Chernozemic soils to determine the effects of incremental N fertilization on grain yield and dry matter accumulation and distribution of six spring wheat (Triticum aestivum L.) cultivars. Urea (46–0–0) was sidebanded at seeding in 40 kg N ha−1 increments from 0 to 240 kg ha−1 in the first year and from 0 to 200 kg ha−1 in the 2 subsequent years. Nitrogen fertilization increased the grain and straw yields of all cultivars in each experiment. The predominant factor affecting the N response and harvest index of each cultivar was available moisture. At two of the three sites, 91% of the interexperiment variability in mean maximum grain yield was explained by variation in root zone moisture at seeding. Mean maximum total dry matter varied by less than 12% among cultivars, but mean maximum grain yield varied by more than 30%. Three semidwarf cultivars, HY 320, Marshall and Solar, had consistently higher grain yield and grain yield response to N than Glenlea and Katepwa, two standard height cultivars, and Len, a semidwarf. The mean maximum grain yield of HY 320 was the highest of the cultivars on test and those of Katepwa and Len the lowest. Len produced the least straw and total dry matter. The level of N fertilization at maximum grain yield varied among cultivars, sites and years. Marshall and Solar required the highest and Len the lowest N rates to achieve maximum grain yield. The year-to-year variation in rates of N fertilization needed to produce maximum grain yield on a specific soil type revealed the limitations of N fertility recommendations based on "average" amounts and temporal distribution of available moisture.Key words: Wheat (spring), N response, standard height, semidwarf, grain yield


1995 ◽  
Vol 5 (1-2) ◽  
pp. 85-99 ◽  
Author(s):  
L. M. Dwyer ◽  
B. L. Ma ◽  
H. N. Hayhoe ◽  
J.L.B. Culley

1989 ◽  
Vol 25 (3) ◽  
pp. 349-355 ◽  
Author(s):  
S. S. Parihar ◽  
R. S. Tripathi

SUMMARYThe response of chickpea to irrigation and phosphorus was studied at Kharagpur in Eastern India. Irrigation scheduling was based on the ratio between irrigation water applied and cumulative pan evaporation (ID/CPE), and had little effect on dry matter accumulation. Increasing the frequency and amount of irrigation reduced the number and dry weight of nodules per plant, which increased to a maximum 70 days after sowing and then declined. Irrigation significantly reduced grain yield as a result of excessive vegetative growth at the expense of pod formation. Application of phosphorus promoted nodulation and increased both nodule dry weight and the concentration of N, P and K in grain and stover. Uptake of N, P and K by the crop was also increased.


Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 401
Author(s):  
Raghavendra Madar ◽  
Yudh Vir Singh ◽  
Mahesh Chand Meena ◽  
Tapas Kumar Das ◽  
Venkatesh Paramesh ◽  
...  

Understanding of the potassium (K) nutrient cycle and its microbial transformation of unavailable forms of soil K to plant-available K is crucial in any agroecosystem for strategic nutrient management through inorganic fertilizer, crop residue (CR), and microbial applications. Therefore, the present investigation was undertaken to study the effect of crop residue and K management practices on crop productivity, K mobilization from native soil K-pool, and crop assimilation of K under a zero-till maize–wheat cropping system. The experiment consisted of four residue levels (0, 2, 4, and 6 Mg ha−1) and five K levels (0, 50%, 100%, 150% RDK [recommended dose of K] and 50% RDK + potassium solubilizing bacteria, KSB). Results showed that CR retention at 6.0 Mg ha−1 significantly improved grain yield (of maize by 10.17%; wheat by 9.87%), dry matter accumulation, K uptake and redistribution in native soil K pools (water soluble K (WSK), exchangeable K (EK) and non-exchangeable K (NEK)) at 30 and 60 days after sowing and at harvest as compared to no CR. Among the K management, 50% RDK+KSB reported significantly higher grain yield (of maize by 26.22%; wheat by 24.70%), dry matter accumulation, K uptake, and native K pools (WSK, EK, and NEK) at different growth stages compared to no K. Total K did not differ significantly due to residue and K management. The highest actual change of K reported with 6.0 Mg ha−1 CR (51 kg ha−1) and 50% RDK+KSB (59 kg ha−1) over control. Significant (p ≤ 0.01) positive correlation was found among grain yield, dry matter accumulation, K uptake, the actual change in K and different native K pools. It can be concluded that retention of 6 Mg ha−1 CR and supply of 50% K through inorganic fertilizer along with seed inoculation of KSB biofertilizers, improved crop growth, productivity by enhancing K assimilation as a consequence of the release of non-exchangeable K and through the application of CR and K treatments under a zero tillage maize–wheat system.


1996 ◽  
Vol 36 (6) ◽  
pp. 695 ◽  
Author(s):  
CP Horn ◽  
CJ Birch ◽  
RC Dalal ◽  
JA Doughton

Mean protein concentrations in wheat (Triticum aestivum) on the Darling Downs of southern Queensland have fallen below 10% in recent years, preventing farmers from obtaining 'Prime Hard' status (13.0%) for their wheat crop. Two management options, for improving this situation are applications of nitrogenous fertiliser in a wheat monoculture or inclusion of a legume in rotation with wheat. Long-term trials at Warra, on the western Darling Downs, resulted in the selection of chickpea (Cicer arietinum) as a useful grain legume cash crop with potential for improvement of its nitrogen (N) fixing ability through management. This 2-year study examined the effect of sowing time and tillage practice on dry matter yield, grain yield, N accumulation and N2 fixation in chickpea and the subsequent soil N balance. There were 3 sowing times during autumn and winter of each year using conventional tillage (CT). Zero tillage (ZT) was introduced after the first crop for all sowing times. Greater total dry matter yield and grain yield (4.18-5.95 and 1.63-2.25 t/ha, respectively) resulted from sowing in autumn or early winter than from sowing in late winter (3.39-3.86 and 0.97-1.22 kg/ha, respectively). The effects of tillage practice were variable, depending on growth stage. At harvest, ZT plots produced greater total dry matter yield (4.20 t/ha) and grain yield (1.94 t/ha) than CT plots (3.01 and 1.29 t/ha, respectively), whereas at the time of maximum dry matter, yield was higher under CT for autumn sowings, and under ZT for winter sowings.


2014 ◽  
Vol 54 (9) ◽  
pp. 1305
Author(s):  
S. M. Robertson

The relationship between pasture height and mass influences the availability of pasture for grazing, and is important for predicting intake of pasture and liveweight change by sheep. The relationship between pasture mass and structure and sheep production is poorly defined for low-mass, clumpy pastures in low-rainfall regions. Between 2001 and 2004, 480 quadrats of pastures were measured in 23 paddocks throughout the Victorian Mallee. Pasture height was related to live mass for medic (linear; r2 = 0.70; P < 0.001) and grassy medic (asymptotic; r2 = 0.64; P < 0.001) pastures, and prediction of grassy medic pasture height was improved by inclusion of proportion live groundcover. During 2004, pasture dry matter accumulation and liveweight changes in sheep grazing annual pastures were measured and compared with predicted outputs from GrazFeed, a software model used to estimate feed intake and liveweight change in sheep. Improved predictions of liveweight gain in grazing sheep were obtained using measured height rather than the GrazFeed default height. The results show that the height to mass relationship of annual pastures in the Victorian Mallee differs between pasture types, between years, and may differ from other published relationships. This study provides information that may assist in the development of models of grazing systems.


1995 ◽  
Vol 35 (4) ◽  
pp. 495 ◽  
Author(s):  
RG Flood ◽  
PJ Martin ◽  
WK Gardner

Total crop dry matter (DM) production and its components, remobilisation of stem reserves, and the relation of these to grain yield were studied in 10 wheat cultivars sown at Walpeup, Boort, and Horsham in the north-western Victorian wheatbelt. Between sites, all DM components decreased in the order Horsham > Boort > Walpeup. Differences between Boort and Walpeup were not always significant. Total DM at anthesis for Walpeu,p and Boort was in a similar range, and less than that for Horsham. Yields increased in the order Walpeup < Boort < Horsham. When data from the 3 sites were combined, leaf, stem (excluding cv. Argentine IX), and total DM were related to grain yield. Within sites, ear DM at anthesis was related to grain yield. Grain yield for all cultivars at Horsham and Walpeup and 5 cultivars at Boort was greater than the increases in crop DM from anthesis to maturity, indicating that pre-anthesis stored assimilates (stem reserves) were used for grain filling. Post-anthesis decrease in stem weight was inversely related to grain yield only at Horsham, which supports the view of utilisation of stem reserves for grain filling at this site. At Boort and Walpeup there was a similar negative trend, but values for 2 cultivars at each site were outliers, which weakened the trend. The wide adaptability of the Australian cultivars used in this study may be related to the differential remobilisation of stem reserves at each site. A measure of yield stability, however, was not related to stem weight loss during the grain-filling period.


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