Development and use of a barley crop simulation model to evaluate production management strategies in north-eastern Australia

1996 ◽  
Vol 47 (7) ◽  
pp. 997 ◽  
Author(s):  
PJ Goyne ◽  
H Meinke ◽  
SP Milroy ◽  
GL Hammer ◽  
JM Hare

A study was undertaken to identify improved management strategies for barley (Hordeum vulgare L.), particularly in relation to time of planting, location, and frost risk in the variable climate of north-eastern Australia. To achieve this objective, a crop growth simulation model (QBAR) was constructed to integrate the understanding, gained from field experiments, of the dynamics of crop growth as influenced by soil moisture and environmental variables. QBAR simulates the growth and yield potential of barley grown under optimal nutrient supply, in the absence of pests, diseases, and weeds. Genotypic variables have been determined for 4 cultivars commonly grown in the northern cereal production areas. Simulations were conducted using long-term weather data to generate the probabilistic yield outcome of cv. Grimmet for a range of times of planting at 10 locations in the north-eastern Australian grain belt. The study indicated that the common planting times used by growers could be too late under certain circumstances to gain full yield potential. Further applications of QBAR to generating information suitable for crop management decision support packages and crop yield forecasting are discussed.

2011 ◽  
Vol 25 (4) ◽  
pp. 521-525 ◽  
Author(s):  
Gulshan Mahajan ◽  
Bhagirath S. Chauhan

Weeds are a major biotic constraint to aerobic rice production in Asia. Research is needed on the effects of cultural practices on weed management in aerobic rice, including techniques such as planting pattern and competitive cultivars. Field experiments were conducted in Punjab, India, in the wet seasons of 2008 and 2009 to study the growth of weeds and two rice cultivars [PR 115 and Punjab (P.) Mehak 1] in relation to planting pattern (uniform rows [23-cm row spacing] and paired rows [15-, 30-, and 15-cm row spacings]) under aerobic conditions. Junglerice and rice flatsedge were the dominant weed species during the early stages of the crop, while Chinese sprangletop and large crabgrass were the predominant species during flowering stage of the crop. Weed dry matter was not affected by planting pattern of P. Mehak 1; however, for PR 115, weed dry matter was greater in rice grown in uniform rows (244 g m−2) than in paired rows (183 g m−2). Planting patterns did not affect weed-free crop growth and yield, but weeds tended to be more abundant in the uniform planting system, particularly under cultivar PR 115. Consequently, this cultivar grew and yielded better under the paired rows when weeds were present. The cultivar PR 115 had greater yield potential than P. Mehak 1, but growth and productivity of P. Mehak 1 were unaffected by the planting patterns, suggesting better competitive ability against weeds than PR 115. The results imply that yield of some aerobic rice cultivars may be improved by exploring competitiveness of rice cultivars through paired row planting patterns. There is a need to study plasticity changes for cultivars which respond with more competiveness in paired rows. The identified traits could be useful as selection criteria for screening weed-competitive cultivars in paired row pattern.


2008 ◽  
Vol 26 (3) ◽  
pp. 585-594 ◽  
Author(s):  
I.M. El-Metwally ◽  
M.T. Abdelhamid

Two field experiments were conducted in two successive seasons, 2005/2006 and 2006/2007, to determine whether management can improve faba bean competitiveness with weeds, thus helping to achieve its yield potential. The experiment included five treatments, composed of organic and mineral fertilizers, alone and mixed at different rates, along with a control and six weed control treatments, including oxadiargyl, prometryn, hand hoeing treatments alone or mixed with the herbicides, and a nonweeded treatment (control).The herbicide treatments were not superior to the two hand-hoeing treatments. Using compost favored growth and yield of faba bean more than of weeds. Adding fertilizer also improved most yield parameters. Application of compost alone or combined with 50 or 100% of the recommended NPK rate improved faba bean growth in terms of net assimilation rate, specific leaf area, and leaf weight ratio as components of relative growth rate. This improvement in growth resulted in increase of seed yield, yield components and protein of faba bean. Faba bean yield performance improved under interactive fertilizer effects and weed control treatments as growth improved, as a result of nutrient release from fertilizers and weed control.


Soil Research ◽  
2011 ◽  
Vol 49 (7) ◽  
pp. 559 ◽  
Author(s):  
Y. P. Dang ◽  
R. C. Dalal ◽  
M. J. Pringle ◽  
A. J. W. Biggs ◽  
S. Darr ◽  
...  

Salinity, sodicity, acidity, and phytotoxic concentrations of chloride (Cl–) in soil are major constraints to crop production in many soils of north-eastern Australia. Soil constraints vary both spatially across the landscape and vertically within the soil profile. Identification of the spatial variability of these constraints will allow farmers to tune management to the potential of the land, which will, in turn, bring economic benefit. For three cropping fields in Australia’s northern grains region, we used electromagnetic induction with an EM38, which measures apparent electrical conductivity of the soil (ECa) and soil sampling to identify potential management classes. Soil Cl– and soluble Na+ concentrations, EC of the saturated extract (ECse), and soil moisture were the principal determinants of the variation of ECa, measured both at the drained upper limit of moisture (UL) and at the lower limit (LL) of moisture extracted by the crop. Grain yield showed a strong negative relation with ECa at both UL and LL, although it was stronger for the latter. We arrive at a framework to estimate the monetary value of site-specific management options, through: (i) identification of potential management classes formed from ECa at LL; (ii) measurement of soil attributes generally associated with soil constraints in the region; (iii) grain yield monitoring; and (iv) simple on-farm experiments. Simple on-farm experiments suggested that, for constrained areas, matching fertiliser application to realistic yield potential, coupled to gypsum amelioration, could potentially benefit growers by AU$14–46/ha.year (fertiliser) and $207/ha.3 years (gypsum).


2020 ◽  
Vol 12 (10) ◽  
pp. 1653
Author(s):  
Yang Chen ◽  
Tim R. McVicar ◽  
Randall J. Donohue ◽  
Nikhil Garg ◽  
François Waldner ◽  
...  

The onus for monitoring crop growth from space is its ability to be applied anytime and anywhere, to produce crop yield estimates that are consistent at both the subfield scale for farming management strategies and the country level for national crop yield assessment. Historically, the requirements for satellites to successfully monitor crop growth and yield differed depending on the extent of the area being monitored. Diverging imaging capabilities can be reconciled by blending images from high-temporal-frequency (HTF) and high-spatial-resolution (HSR) sensors to produce images that possess both HTF and HSR characteristics across large areas. We evaluated the relative performance of Moderate Resolution Imaging Spectroradiometer (MODIS), Landsat, and blended imagery for crop yield estimates (2009–2015) using a carbon-turnover yield model deployed across the Australian cropping area. Based on the fraction of missing Landsat observations, we further developed a parsimonious framework to inform when and where blending is beneficial for nationwide crop yield prediction at a finer scale (i.e., the 25-m pixel resolution). Landsat provided the best yield predictions when no observations were missing, which occurred in 17% of the cropping area of Australia. Blending was preferred when <42% of Landsat observations were missing, which occurred in 33% of the cropping area of Australia. MODIS produced a lower prediction error when ≥42% of the Landsat images were missing (~50% of the cropping area). By identifying when and where blending outperforms predictions from either Landsat or MODIS, the proposed framework enables more accurate monitoring of biophysical processes and yields, while keeping computational costs low.


2019 ◽  
Vol 11 (3) ◽  
pp. 706 ◽  
Author(s):  
Xinbing Wang ◽  
Yuxin Miao ◽  
Rui Dong ◽  
Zhichao Chen ◽  
Yanjie Guan ◽  
...  

Precision nitrogen (N) management (PNM) strategies are urgently needed for the sustainability of rain-fed maize (Zea mays L.) production in Northeast China. The objective of this study was to develop an active canopy sensor (ACS)-based PNM strategy for rain-fed maize through improving in-season prediction of yield potential (YP0), response index to side-dress N based on harvested yield (RIHarvest), and side-dress N agronomic efficiency (AENS). Field experiments involving six N rate treatments and three planting densities were conducted in three growing seasons (2015–2017) in two different soil types. A hand-held GreenSeeker sensor was used at V8-9 growth stage to collect normalized difference vegetation index (NDVI) and ratio vegetation index (RVI). The results indicated that NDVI or RVI combined with relative plant height (NDVI*RH or RVI*RH) were more strongly related to YP0 (R2 = 0.44–0.78) than only using NDVI or RVI (R2 = 0.26–0.68). The improved N fertilizer optimization algorithm (INFOA) using in-season predicted AENS optimized N rates better than the N fertilizer optimization algorithm (NFOA) using average constant AENS. The INFOA-based PNM strategies could increase marginal returns by 212 $ ha−1 and 70 $ ha−1, reduce N surplus by 65% and 62%, and improve N use efficiency (NUE) by 4%–40% and 11%–65% compared with farmer’s typical N management in the black and aeolian sandy soils, respectively. It is concluded that the ACS-based PNM strategies have the potential to significantly improve profitability and sustainability of maize production in Northeast China. More studies are needed to further improve N management strategies using more advanced sensing technologies and incorporating weather and soil information.


Plant Disease ◽  
2005 ◽  
Vol 89 (5) ◽  
pp. 515-520 ◽  
Author(s):  
H. M. Booker ◽  
P. Umaharan ◽  
C. R. McDavid

Field experiments were carried out in St. Augustine, Trinidad & Tobago, West Indies to determine the effects of time of inoculation of Cowpea severe mosaic virus (CPSMV) and cultivar on crop growth and yield in cowpea (Vigna unguiculata). Crop growth and yield loss were investigated through growth analysis and yield component analysis on three cultivars in two seasons (wet and dry). Time of inoculation had the most profound impact on yield. Inoculations during the early log phase (seedling stage), 12 days after seeding (DAS), consistently had the greatest impact (50 to 85% yield loss) compared with those inoculated during the exponential growth phase (24 DAS; 22 to 66% yield loss) or linear growth phase (35 DAS; 2 to 36% yield loss). The effects were particularly pronounced in the dry season and in the more determinate cultivar, H8-8-27. Reduction in maximum leaf area index, leaf area duration, or maximum vegetative dry matter explained reductions in yield. Yield reductions resulted primarily from reduced pod number per plant and, to a lesser extent, from reduced average pod dry weight. The results show that CPSMV control measures should be aimed at delaying infection by CPSMV to minimize the impact on cowpea yield.


2007 ◽  
Vol 17 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Lingxiao Zhang ◽  
S Kyei-Boahen

Soybean (Glycine max) grown as a vegetable is gaining in popularity in the U.S. and demand is expected to increase over the long term. However, information on production in the U.S. is limited because most of the product is imported. Field experiments were conducted at Stoneville, Miss., in 2004 and 2005 to evaluate the production and yield potential and to estimate the net returns for sustainable production in the Mississippi Delta. In 2004, four vegetable soybean varieties were evaluated and 23 varieties were evaluated in 2005. The varieties varied from maturity group III to VII. The late-maturing varieties were generally taller, had more nodes/plant, pods/plant, and fresh green pod yield at R6 stage (full seed) than the early-maturing varieties. Fresh green bean yield ranged from 1438 to 19,119 lb/acre in 2004. The mean bean yield for the 18 Apr. 2005 planting was 26,538 lb/acre compared with a mean of 18,131 lb/acre for the 10 May 2005 planting. Interaction occurred between planting date and variety as well as soil type and variety for all the variables evaluated. ‘Envy’ produced the lowest yield, whereas ‘Garden Soy 01’, ‘Garden Soy 21’, ‘Midori Giant’, ‘Mojo Green’, and ‘Moon Cake’ produced the highest fresh bean yield. The estimated net returns, using the Mississippi State Budget Generator as a guide, indicated more than twice the returns from growing the regular commodity soybean. The data suggest that vegetable soybean can fit well into the existing cropping system and could be a viable alternative crop for growers in the Mississippi Delta who want to capitalize on a niche market.


Weed Science ◽  
2015 ◽  
Vol 63 (3) ◽  
pp. 710-722 ◽  
Author(s):  
Neith G. Little ◽  
Charles L. Mohler ◽  
Quirine M. Ketterings ◽  
Antonio DiTommaso

Sufficient fertility is important for crop growth and yield but supplying a balanced amount of N, P, and K with compost and manure is a challenge and nutrient imbalances can benefit weeds more than crops. The goal of this study was to compare the aboveground growth responses of common northeastern U.S. crops and weeds to addition of composted poultry manure (CPM). A secondary goal was to test whether the observed growth responses to CPM could be attributed to the three macronutrients—N, P, and K—supplied in the CPM. Two field experiments were conducted over 2 yr. Species grown were corn, lettuce, kale, Powell amaranth, common lambsquarters, giant foxtail, and velvetleaf. Plants were grown in soil amended with CPM or single-nutrient organic N, P, and K fertility amendments. Single-nutrient P treatments with bone char did not adequately mimic P supply from CPM. In both years, biomass of all weeds studied increased with CPM amendment rate. Powell amaranth was the most responsive to CPM addition, increasing 1,775 and 159% from the control to the highest CPM rate in 2010 and 2011, respectively. Corn biomass increased by 22% with CPM rate in 2010 but did not increase with CPM rate in 2011. Lettuce biomass increased with CPM amendment rate (175% in 2010 and 109% in 2011), but due to the increased weed biomass at high CPM amendment rates, good weed control will be necessary to maintain this yield benefit. The increase in growth of Powell amaranth, common lambsquarters, and giant foxtail with CPM amendment was not due to N or K, and may have been influenced by P or another factor in the CPM. Velvetleaf was the only species that exhibited increased biomass with N addition (as blood meal), similarly to the increase with added CPM, suggesting the velvetleaf growth response to CPM was due to N in the CPM. The results show that nutrient ratios should be considered when applying organic amendments, because application rates of organic amendments that meet the crop's needs for one nutrient may oversupply other nutrients. Overfertilization will not benefit crop yield, but the results of this study show that high organic fertility application rates are likely to increase weed growth.


1988 ◽  
Vol 24 (2) ◽  
pp. 247-252 ◽  
Author(s):  
G. O. Iremiren

SUMMARYField experiments were carried out during the rainy seasons of 1985 and 1986 to examine the frequency of weeding necessary for the optimum growth and yield of okra in Nigeria. Weed removal within 12 weeks of sowing generally resulted in significantly better crop growth and yield than that in the weedy check. Weeding once as early as four weeks was as beneficial to okra growth and yield as two or three weedings later in the 12 week period. Weed removal four times at 3, 6, 9 and 12 weeks significantly enhanced crop growth and pod yield over all other treatments. For good pod yields, protection from weed competition over most of the duration of crop growth is therefore essential. Such weed removal may enhance crop yield partly by increasing aeration and water movement in the soil.


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