Effects of below-ground nitrogen on N balances of field-grown fababean, chickpea, and barley

2003 ◽  
Vol 54 (4) ◽  
pp. 333 ◽  
Author(s):  
Dil F. Khan ◽  
Mark B. Peoples ◽  
Graeme D. Schwenke ◽  
Warwick L. Felton ◽  
Deli Chen ◽  
...  
Keyword(s):  
N2 Fixation ◽  
Cropping Systems ◽  
Natural Abundance ◽  
Yield Data ◽  
Soil Enrichment ◽  
15N Enrichment ◽  
South Wales ◽  
Peak Biomass ◽  
Below Ground ◽  
15N Urea

The objectives of this study were to quantify below-ground nitrogen (BGN) of rainfed fababean (Vicia faba), chickpea (Cicer arietinum), and barley (Hordeum vulgare) and to use the values to determine N balances for the 3 crops. The BGN fraction of legumes in particular represents a potentially important pool of N that has often been grossly underestimated or ignored in calculating such balances. A field experiment was conducted at Breeza on the Liverpool Plains, New South Wales, in which BGN of fababean, chickpea, and barley was estimated using 15N methodologies. Plants were grown in 0.32-m2 microplots and labelled with 15N on 5 occasions during vegetative growth with a total of 1.0 mL of 0.5% 15N urea (98 atom% 15N) using leaf-flap (fababean), leaf-tip (barley), or cut petiole (chickpea) shoot-labelling procedures. At peak biomass (146–170 days after sowing), all plant material and soil to 45 cm depth was sampled from one microplot in each replicate plot and analysed for dry matter (DM), %N, and 15N. At plant maturity, the remaining 3 microplots in each replicate plot were harvested for shoot and grain DM and N. With fababean, 15N enrichments of intact roots and shoots were reasonably uniform at 537‰ and 674‰, respectively. Microplot soil at 0–25 cm depth had a 15N enrichment of 18‰ (natural abundance of 6.1‰). The 25–45 cm soil enrichment was 8.7‰ (natural abundance of 6.3‰). In contrast, 15N enrichment of chickpea shoots was about twice that of recovered roots (685‰ v. 331‰), and the soil enrichment was relatively high (30‰ and 8.8‰ for the 0–25 and 25–45 cm depths, respectively). The 15N enrichments of barley shoots and recovered roots were 2272‰ and 1632‰, respectively, with soil enrichments of 34‰ and 10.7‰ for the 0–25 and 25–45 cm depths, respectively. Estimates of BGN as a percentage of total plant N, after adjusting the 15N shoot-labelling values of fababean and chickpea for uneven distribution of 15N-depleted nodules, were 24% for fababean, 68% for chickpea, and 36% for barley. The BGN values were combined with N2 fixation (fababean and chickpea only) and shoot and grain yield data (all 3 species) to construct N budgets. The inclusion of BGN in the budgets increased N balances by 38 kg N/ha to +36 kg N/ha for fababean and by 93 kg N/ha to +94 kg N/ha for chickpea. As there was no external (N2 fixation) input of N to barley, the inclusion of BGN made no difference to the N balance of the crop of –74 kg N/ha. Such values confirm the importance of BGN of N2-fixing legumes in the N economies of cropping systems.

Nitrogen fixation in chickpea. II. Comparison of 15N enrichment and 15N natural abundance methods for estimating nitrogen fixation

1995 ◽  
Vol 46 (1) ◽  
pp. 225 ◽  
Author(s):  
JA Doughton ◽  
PG Saffigna ◽  
I Vallis ◽  
RJ Mayer
Keyword(s):  
Nitrogen Fixation ◽  
N2 Fixation ◽  
Full Range ◽  
15N Natural Abundance ◽  
Natural Abundance ◽  
Enrichment Method ◽  
Mineral N ◽  
Crop Establishment ◽  
15N Enrichment ◽  
15N Natural Abundance Method

The 15N enrichment and 15N natural abundance methods for estimating N2 fixation in chickpea were compared over a range of soil NO3-N levels at crop establishment varying from 10 to 326 kg N/ha (0-120 cm depth). Barley was used as a non-N2 fixing control crop. Both methods estimated reduced N2 fixation as soil NO3-N levels at crop establishment increased. Similar estimates of % N2 fixation were obtained at high values, but at low values the enrichment method gave lower estimates, some of which were negative. The 15N natural abundance method provided realistic estimates of % N2 fixation across all soil N03-N levels at crop establishment. An asymptotic curve described a close ( R2 = 0.95) relationship between these factors. Standard errors of estimates of means for the 15N natural abundance method remained acceptable and relatively stable over the full range of measurements; however, with the 15N enrichment method they became unacceptably large at low values of % N2 fixation. These large errors may have been partly due to legume and control plants assimilating mineral N of differing 15N enrichment. High mineral N levels associated with low values of % N2 fixation were also shown to reduce reliability of N2 fixation values estimated by the 15N enrichment method. These errors caused potentially greater inaccuracy at low values of % N2 fixation than at high values. To compare N2 fixation means statistically, transformations were necessary to stabilize variance and to impart lower weightings to plots with low values of % N2 fixation.

Faba beans and other legumes add nitrogen to irrigated cotton cropping systems

1998 ◽  
Vol 38 (3) ◽  
pp. 253 ◽  
Author(s):  
I. J. Rochester ◽  
M. B. Peoples ◽  
G. A. Constable ◽  
R. R. Gault
Keyword(s):  
Faba Bean ◽  
Dry Matter ◽  
Cropping Systems ◽  
Pigeon Pea ◽  
Adzuki Bean ◽  
Soil N ◽  
South Wales ◽  
Peak Biomass ◽  
Legume Crops ◽  
Faba Beans

Summary. Legumes have become common rotation crops in cotton cropping systems in northern New South Wales. Levels of nitrogen fixation and yield achieved on-farm were measured in commercial faba beans and other winter and summer legume crops sown after cotton over 3 years to assess the relative inputs of fixed nitrogen (N) into this system. Faba bean crops fixed up to 350 kg N/ha, removed up to 160 kg N/ha in harvested grain and contributed up to 270 kg fixed N/ha to soil N after harvest. Grain yields, N2 fixation and dry matter production were reduced in late-sown crops and those water-stressed during pod-filling, but most faba bean crops fixed almost 3 times as much N as was removed in grain. Below-ground legume N, determined with 15N shoot feeding techniques, accounted for 40% of the total crop N at peak biomass, or about 100 kg N/ha for the average faba bean crops. Residual fixed N after harvest was predicted from crop dry matter and grain yield, and this could be used to assess the contribution to soil N from faba beans. Amounts of nitrogen fixed by other legume crops ranged from 20 kg N/ha for adzuki bean and droughted lablab to more than 450 kg N/ha by irrigated soybean. Soybean, peanut and Dolichos lablab contributed more fixed N to the soil than adzuki bean, mung bean or pigeon pea under irrigated conditions. Winter crops including field peas, lentils and lupins and green-manured pasture species fixed up to 240 kg N/ha.

The nitrogen economy of broadacre lupin in southwest Australia

1994 ◽  
Vol 45 (1) ◽  
pp. 149 ◽  
Author(s):  
MJ Unkovich ◽  
JS Pate ◽  
J Hamblin
Keyword(s):  
N2 Fixation ◽  
Crop Residues ◽  
Nitrogen Accumulation ◽  
Study Region ◽  
South West ◽  
Peak Biomass ◽  
Below Ground ◽  
Southwest Australia ◽  
Total Plant ◽  
Time Courses

The time courses of above- and below-ground accumulation of biomass and N were followed in a crop of narrowleaf lupin (Lupinus angustifolius L. cv. Illyarrie) at Geraldton, W.A., and concurrent N2 fixation assessed using the 15N natural abundance technique. Crop biomass peaked at 10 t DM and 231 kg N ha-1 with 13% of this N below ground. The crop accumulated the bulk (90%) of its N through symbiotic N2 fixation. Of the 164 kg total plant N ha-1 remaining in recoverable biomass at maturity 44% was recovered as grain, 49% as other above-ground residues and 7% as roots. Despite a decrease in recoverable N of 67 kg ha-1 between peak biomass and maturity, 96 kg N ha-1 was returned as crop residues after grain harvest. Investigation of six farm crops in the study region gave values for nitrogen accumulation at peak biomass ranging from 199 to 372 kg ha-1 of which, on average, 86% (222 kg ha-1) was fixed from the atmosphere. Predicted N returns to the soil from fixation averaged 65 kg ha-1, though the range (32-96 kg ha-1) indicated that south-west Australian lupin crops provide somewhat variably sized pools of mineralizeable crop residues for following cereal growth.

scholarly journals Symbiotic N2 fixation by soybean in organic and conventional cropping systems estimated by 15N dilution and 15N natural abundance

2007 ◽  
Vol 290 (1-2) ◽  
pp. 69-83 ◽  
Author(s):  
A. Oberson ◽  
S. Nanzer ◽  
C. Bosshard ◽  
D. Dubois ◽  
P. Mäder ◽  
...  
Keyword(s):  
N2 Fixation ◽  
Cropping Systems ◽  
15N Natural Abundance ◽  
Natural Abundance ◽  
Symbiotic N2 Fixation ◽  
15N Dilution

scholarly journals Identifying maize yield and precipitation gaps in Uganda

2021 ◽  
Vol 3 (5) ◽  
Author(s):  
Terence Epule Epule ◽  
Driss Dhiba ◽  
Daniel Etongo ◽  
Changhui Peng ◽  
Laurent Lepage
Keyword(s):  
Cropping Systems ◽  
Growing Season ◽  
Maize Yield ◽  
Sub Saharan Africa ◽  
World Bank Group ◽  
Precipitation Data ◽  
Yield Data ◽  
Yield Gaps ◽  
Maize Yields ◽  
Growing Season Precipitation

AbstractIn sub-Saharan Africa (SSA), precipitation is an important driver of agricultural production. In Uganda, maize production is essentially rain-fed. However, due to changes in climate, projected maize yield targets have not often been met as actual observed maize yields are often below simulated/projected yields. This outcome has often been attributed to parallel gaps in precipitation. This study aims at identifying maize yield and precipitation gaps in Uganda for the period 1998–2017. Time series historical actual observed maize yield data (hg/ha/year) for the period 1998–2017 were collected from FAOSTAT. Actual observed maize growing season precipitation data were also collected from the climate portal of World Bank Group for the period 1998–2017. The simulated or projected maize yield data and the simulated or projected growing season precipitation data were simulated using a simple linear regression approach. The actual maize yield and actual growing season precipitation data were now compared with the simulated maize yield data and simulated growing season precipitation to establish the yield gaps. The results show that three key periods of maize yield gaps were observed (period one: 1998, period two: 2004–2007 and period three: 2015–2017) with parallel precipitation gaps. However, in the entire series (1998–2017), the years 2008–2009 had no yield gaps yet, precipitation gaps were observed. This implies that precipitation is not the only driver of maize yields in Uganda. In fact, this is supported by a low correlation between precipitation gaps and maize yield gaps of about 6.3%. For a better understanding of cropping systems in SSA, other potential drivers of maize yield gaps in Uganda such as soils, farm inputs, crop pests and diseases, high yielding varieties, literacy, and poverty levels should be considered.

Changes in soil carbon under long-term maize in monoculture and legume-based rotation

2001 ◽  
Vol 81 (1) ◽  
pp. 21-31 ◽  
Author(s):  
E G Gregorich ◽  
C F Drury ◽  
J A Baldock
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Magnetic Resonance ◽  
Soil Carbon ◽  
Crop Residues ◽  
Cropping Systems ◽  
Natural Abundance ◽  
Organic C ◽  
Soil C

Legume-based cropping systems could help to increase crop productivity and soil organic matter levels, thereby enhancing soil quality, as well as having the additional benefit of sequestering atmospheric C. To evaluate the effects of 35 yr of maize monoculture and legume-based cropping on soil C levels and residue retention, we measured organic C and 13C natural abundance in soils under: fertilized and unfertilized maize (Zea mays L.), both in monoculture and legume-based [maize-oat (Avena sativa L.)-alfalfa (Medicago sativa L.)-alfalfa] rotations; fertilized and unfertilized systems of continuous grass (Poa pratensis L.); and under forest. Solid state 13C nuclear magnetic resonance (NMR) was used to chemically characterize the organic matter in plant residues and soils. Soils (70-cm depth) under maize cropping had about 30-40% less C, and those under continuous grass had about 16% less C, than those under adjacent forest. Qualitative differences in crop residues were important in these systems, because quantitative differences in net primary productivity and C inputs in the different agroecosystems did not account for observed differences in total soil C. Cropping sequence (i.e., rotation or monoculture) had a greater effect on soil C levels than application of fertilizer. The difference in soil C levels between rotation and monoculture maize systems was about 20 Mg C ha-1. The effects of fertilization on soil C were small (~6 Mg C ha-1), and differences were observed only in the monoculture system. The NMR results suggest that the chemical composition of organic matter was little affected by the nature of crop residues returned to the soil. The total quantity of maize-derived soil C was different in each system, because the quantity of maize residue returned to the soil was different; hence the maize-derived soil C ranged from 23 Mg ha-1 in the fertilized and 14 Mg ha-1 in the unfertilized monoculture soils (i.e., after 35 maize crops) to 6-7 Mg ha-1 in both the fertilized and unfertilized legume-based rotation soils (i.e., after eight maize crops). The proportion of maize residue C returned to the soil and retained as soil organic C (i.e., Mg maize-derived soil C/Mg maize residue) was about 14% for all maize cropping systems. The quantity of C3-C below the plow layer in legume-based rotation was 40% greater than that in monoculture and about the same as that under either continuous grass or forest. The soil organic matter below the plow layer in soil under the legume-based rotation appeared to be in a more biologically resistant form (i.e., higher aromatic C content) compared with that under monoculture. The retention of maize residue C as soil organic matter was four to five times greater below the plow layer than that within the plow layer. We conclude that residue quality plays a key role in increasing the retention of soil C in agroecosystems and that soils under legume-based rotation tend to be more “preservative” of residue C inputs, particularly from root inputs, than soils under monoculture. Key words: Soil carbon, 13C natural abundance, 13C nuclear magnetic resonance, maize cropping, legumes, root carbon

An economic comparison of alternative and traditional cropping systems in the northern Great Plains, USA

2006 ◽  
Vol 21 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Eric A. DeVuyst ◽  
Thomas Foissey ◽  
George O. Kegode
Keyword(s):  
North Dakota ◽  
Great Plains ◽  
Cropping Systems ◽  
Cropping System ◽  
Conventional Tillage ◽  
Northern Great Plains ◽  
Yield Data ◽  
Government Program ◽  
Current Production ◽  
Commodity Programs

AbstractCurrent production practices in the Red River Valley of North Dakota and Minnesota involve use of extensive tillage and/or herbicides to control weeds. Given the erosion potential, environmental concerns associated with herbicides, and herbicide-resistant weeds, alternative cropping systems that mitigate these problems need to be assessed economically. Furthermore, the role that government commodity programs play in the adoption of more ecologically friendly cropping systems needs to be determined. We evaluated 8 years of yield data (1994–2001) from field plots near Fargo, North Dakota, to compare the economics of two alternative cropping systems, reduced-input (RI) and no-till (NT), to a conventional tillage (CT) cropping system. The RI system relies on a more diverse rotation of soybean (SB), spring wheat (SW), sweet clover (SC) and rye, and uses fewer herbicide and fertilizer inputs than CT or NT. Both NT and CT systems rotate SB and SW. We found that CT returns averaged over $47 ha−1more than NT during the study period. Because SC yield data were not available, the economic competitiveness of RI was calculated using break-even yields and returns for SC. Historical SC yields in Cass County, North Dakota were not statistically different from the break-even yields. However, when government program payments were considered, break-even returns for SC increased by about $15 and $18 ha−1and break-even yields by 0.44 and 0.52 MT ha−1for RI to compare with NT and CT, respectively. These results indicate that CT management offers greater economic return than either RI or NT and that government program payments impede adoption of more environmentally friendly cropping systems in the northern Great Plains.

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