Effects of grazing on wheat growth, yield, development, water use, and nitrogen use

2006 ◽  
Vol 57 (12) ◽  
pp. 1307 ◽  
Author(s):  
J. M. Virgona ◽  
F. A. J. Gummer ◽  
J. F. Angus

The effect of grazing by sheep during the late vegetative and early reproductive phases was measured on long-duration wheat crops in 2 experiments on farms in southern NSW. In both experiments, grazed and non-grazed crops were compared with different N-fertiliser strategies. In the first experiment, grazing 40 dry-sheep equivalents (DSE)/ha for 19 days increased grain yield from 2.30 to 2.88 t/ha in a season with a dry early spring. The second experiment, in a more favourable season, compared 6 durations of grazing by an average of 32 DSE/ha. The effects of grazing varied from no yield reduction with 15 days of grazing to a reduction from 5.97 to 3.98 t/ha with 51 days of grazing. In both experiments grazing caused slower crop development, with about 1 day’s delay in anthesis and maturity for every 4–5 days of grazing. Different patterns of water use by grazed and non-grazed crops, combined with delayed development, explained much of the effects of grazing on yield. The soil accumulated more water during grazing, which was used during grain filling when water-use efficiency for grain production was high. Delayed development also allowed grazed crops to respond to later rain. In the second experiment, grazing resulted in a net loss of 38 kg N/ha from the crop. Despite reduced N levels, the grazed crops showed no greater ability than grain-only crops to recover fertiliser N. The effect of the low recovery was that N removed during grazing was not efficiently replaced by fertiliser.

2012 ◽  
Vol 212-213 ◽  
pp. 578-585
Author(s):  
Zhong Wen Yang ◽  
Jun Ying Jin ◽  
Xin Yi Xu

Water stress is an important approach to use water resources efficiently and remit the agricultural water shortage. Hemarthria compressa is one of perennial grasses, a pasture of high quality, which has abundant species resources in China. To explore the response of the growth, yield and water use efficiency(WUE) of Hemarthria compressa under water stress, this study, adapting pot experiment, imposed three water stress degree (LD, MD and SD) treatments and a control treatment on Hemarthria compressa. The data of growth indicators during control period, yield and total water consumption were obtained. The results show a noticeable inhibitory action of water stress on the growth of Hemarthria compressa. Along with the intensifying of water stress, plant height increment, leaf area, total biomass, dry matter of each organ and yield decreased, and the root-shoot ratio increased firstly and inclined to slump finally. Plants under the middle water stress treatment achieved the greatest WUE of 38.25 kg/m3. The first 10d in the water control period was the most sensitive period of the pasture responding to water stress.


Helia ◽  
2001 ◽  
Vol 24 (35) ◽  
pp. 111-128
Author(s):  
Víctor M. Olalde G. ◽  
J. Alberto Escalante E. ◽  
Angel A. Mastache L.

SUMMARYDuring the rainy season of 1998, a field experiment was established in Cocula, Guerrero (hot subhumid climate, Awo) and in Montecillo, México (semiarid climate, BS1), to evaluate the effect of nitrogen (0, 10 and 20 g m-2) and environment on phenology, yield and its components, water use efficiency (WUE), and crop evapotranspiration (ETc) and heat units (HU) accumulated during the growth cycle of sunflower (Helianthus annuus L.) cv. Victoria. The crop was planted on June 1 at a density of 7.5 pl m-2 in both climates. In Cocula, maximum and minimum temperatures were more extreme and rainfall was more intense, while soil was poor in total nitrogen, compared with Montecillo. Crop growth, yield and its components, and water use efficiency were affected significantly by the environment, nitrogen and the interaction environment * nitrogen. The crop cycle in the hot environment was 36 days shorter, with a greater accumulation of HU and ETc. Yield and its components and water use efficiency were significantly higher in Cocula. Nitrogen positively affected the evaluated variables. The interactive effect of environment * nitrogen was observed clearly, since in Cocula there was response to the application of nitrogen in most of the variables evaluated, while in Montecillo there was not.


1983 ◽  
Vol 34 (3) ◽  
pp. 229 ◽  
Author(s):  
GK McDonald ◽  
BG Sutton ◽  
FW Ellison

The effect of time of sowing on the yield of 15 wheat cultivars grown under irrigation was examined at Narrabri, N.S.W. Sowing dates, which ranged from mid-April to mid-August, encompassed the period of sowing normally found with commercial crops. The length of the pre-anthesis period was affected by both temperature and photoperiod. There was evidence of a vernalization requirement for some of the winter and midseason cultivars, but, overall, photoperiod was the more important environmental factor determining pre-anthesis development. Each day's delay in sowing caused a delay of between 0.48 and 0.75 days in anthesis; the delays observed for spring wheats were generally greater than those reported for dryland wheat in eastern Australia. Winter cultivars generally did not show an optimum sowing or anthesis date. For spring cultivars, the optimum time of sowing was early June (range of about 3 weeks), while the optimum anthesis date was the last week of September (range of 1 week). Grain yields of spring cultivars were reduced by 6 and 16% per week's delay in sowing and anthesis respectively. Despite a non-limiting water supply, yields at late plantings were low, which was largely the result of hastened crop development and high temperatures during grain-filling. The environmental factors which determined the optimum sowing and anthesis dates were the incidence of early spring frosts and high spring temperatures. If frosts were not a factor at Narrabri, the optimum time of flowering would be 6-8 weeks earlier than the present optimum.


2016 ◽  
Vol 13 (2) ◽  
pp. 94-107 ◽  
Author(s):  
S Roy ◽  
M Barman ◽  
AM Puste ◽  
SK Gunri ◽  
K Jana

Field experiment was conducted at Instructional Farm, Jaguli (Mohanpur), Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India during two consecutive summer seasons of 2010-11, and 2011-12. The experiment was laid out in split-plot design having 4 levels of irrigation– rainfed without mulch, rainfed with mulch, irrigation at IW (depth of irrigation water) / CPE (Cumulative pan evaporation) ratios of 0.5 and 0.75 in main-plot and 4 inter cropping systems, sole maize, sole mungbean, maize + mungbean (1:1 row ratio) and maize + mungbean (3:2 row ratio) considered as sub-plot treatments replicated thrice. Results revealed that application of irrigation and intercropping systems markedly influenced the growth, yield and yield components (number of cobs/plant, number of grains/cob in case of maize and number of pods/plant and number of seeds/pod in case of mungbean) where the maximum value of these components were recorded with the application of irrigation at IW/CPE ratio 0.75 in sole crop. Maize-mungbean in 3:2 row ratio yielded higher than that of 1:1 intercropping system which might be due to less light interception and more competition for water and nutrition between both the crops. CU of water increased with the increasing levels of irrigation and the maximum value (17.75 kg ha-1 mm- 1) of WUE (water use efficiency) was observed with irrigation at IW: CPE ratio 0.75 under intercropping system of maize : mungbean in 3:2 row ratio followed by IW: CPE ratio 0.50. Among the sole crop, maximum WUE was with IW/CPE ratio 0.75 might be due to more consumption of water corresponding to production potential of maize, while, it was more under rainfed with mulch in mungbean. The relative crowding coefficient (RCC) also revealed both the intercropping systems were advantageous and the land equivalent ratio (LER) increased with the level of irrigation.Thus, maize grown in association with mungbean (3:2 row ratio) were found to be more profitable (B:C ratio of 2.58) with higher monetary advantage as compared to sole crop of maize (B:C ratio of 1.98) with the application of irrigation at IW: CPE ratio of 0.75 in new alluvial zone of West Bengal.SAARC J. Agri., 13(2): 94-107 (2015)


2019 ◽  
Vol 70 (1) ◽  
pp. 781-808 ◽  
Author(s):  
Andrew D.B. Leakey ◽  
John N. Ferguson ◽  
Charles P. Pignon ◽  
Alex Wu ◽  
Zhenong Jin ◽  
...  

The ratio of plant carbon gain to water use, known as water use efficiency (WUE), has long been recognized as a key constraint on crop production and an important target for crop improvement. WUE is a physiologically and genetically complex trait that can be defined at a range of scales. Many component traits directly influence WUE, including photosynthesis, stomatal and mesophyll conductances, and canopy structure. Interactions of carbon and water relations with diverse aspects of the environment and crop development also modulate WUE. As a consequence, enhancing WUE by breeding or biotechnology has proven challenging but not impossible. This review aims to synthesize new knowledge of WUE arising from advances in phenotyping, modeling, physiology, genetics, and molecular biology in the context of classical theoretical principles. In addition, we discuss how rising atmospheric CO2concentration has created and will continue to create opportunities for enhancing WUE by modifying the trade-off between photosynthesis and transpiration.


Sign in / Sign up

Export Citation Format

Share Document