Effects of eight year rotations of grain sorghum with lucerne, annual legume, wheat and long fallow on nitrogen and organic carbon in two contrasting soils

Soil Research ◽  
1990 ◽  
Vol 28 (2) ◽  
pp. 277 ◽  
Author(s):  
ICR Holford

Soil nitrogen and organic carbon levels during 8-year rotations of grain sorghum (4 years) with lucerne (4 years), annual legume (faba beans or cowpeas in alternate years), wheat (4 years) and long fallow (alternate years) were measured on a black earth and a red clay in northern New South Wales. Total soil nitrogen (0-15 cm) increased at about 100 kg ha-1 yr-1 in the lucerne leys, but it maximized after 2 years on the red clay and then declined at about the same rate, suggesting that nitrogen fixation had ceased in response to heavy grazing pressure and drought conditions. The positive effects of lucerne on total nitrogen and organic carbon were maintained during 4 years of subsequent sorghum growth on the black earth, but effects on the red clay were not significant. Sorghum, when its residues were incorporated, had a much larger effect than lucerne in raising soil organic carbon. Concentrations of soil nitrate were much higher immediately after the lucerne than after continuous cereal, and they remained higher in the lucerne rotations after 2 years of sorghum. Accumulation of nitrate during long fallows was much larger after sorghum, with incorporated residues, than after no-tilled wheat, and the magnitude of this difference suggested biological nitrogen fixation by free-living bacteria during the sorghum long fallows. Fluctuations in nitrate were generally larger in the red clay than in the black earth, but sorghum yields and nitrogen uptake were less responsive to high nitrate in the red clay, apparently because of its lower nitrate buffering capacity and poorer soil structure. In comparison with continuous cereal growing, the annual legume rotation had no significant effect on organic carbon or total nitrogen, but it sometimes increased nitrate during the sorghum rotation, probably by a nitrate sparing effect during the cowpea crop.

1989 ◽  
Vol 40 (2) ◽  
pp. 255 ◽  
Author(s):  
ICR Holford

Long-term yields, nitrogen uptake and responsiveness of grain sorghum following three lucerne rotations, an annual legume rotation, long fallowing, and continuous wheat growing were measured on a black earth and red clay in northern New South Wales. The three lucerne rotations compared two methods of lucerne establishment (with or without a cover crop) and two methods of grazing management (short or extended grazing).There were large beneficial effects of lucerne leys on the first grain sorghum crop, whether they were measured as grain yield, nitrogen content of the foliage and grain, or nitrogen uptake. The effect was much smaller in the second year but it increased in the third and fourth years, in direct relation to the rainfall during the sorghum flowering period. The effect was larger on the black earth than on the red clay, reflecting the much higher lucerne yields on the former soil. Evidence indicated that the nitrogen contribution from lucerne after the first year was no greater than the nitrogen accumulated by long fallowing, and this was attributed to very low rainfall and lucerne yields during the four year ley period.The annual legume rotation suffered from drought and insect damage in most years, and following sorghum yields tended to be lower than those achieved by long fallowing.Differences in the effects of establishment method and grazing management on total lucerne yields were reflected in the differences in subsequent grain sorghum yields. Largest differences were on the black earth where extended grazing lowered the total yields of lucerne and subsequent grain sorghum. Sowing lucerne under wheat had little effect on total yields of lucerne or sorghum.


2013 ◽  
Vol 664 ◽  
pp. 142-145
Author(s):  
Shan Shan Zhang ◽  
Li Yuan Yang ◽  
Hui Wang ◽  
Qing Lin Chen ◽  
Qian Li

In order to explore the variations and impact factors of soil nitrogen contents, 0-20 cm mineral soil under herb, shrub, Platycladus orientalis plantation of limestone mountains after restoration for 5 years and 10 years were collected and examined in Jinan, Shandong province. The results showed that there was different soil mineral nitrogen content under different vegetation during the natural succession and artificial restoration succession. Shrub community (14.35 mg/Kg) > herb community (12.73 mg/Kg); Platycladus orientalis plantation restored for 10 years (27.82 mg/Kg) > Platycladus orientalis plantation restored for 5 years (20.76 mg/Kg). NO3--N has highly significant positive correlations with soil organic carbon and total nitrogen content (r = 0.626, 0.564, p 4+-N has not significantly correlated with total nitrogen and organic carbon content (r = 0.218, 0.155). However, it has highly significant positive correlation with the NO3--N (r = 0.531, p 3--N and NH4+-N have highly significant negative correlations with soil pH (r = -0.657, -0.605, p < 0.01), respectively. But the correlation with the soil moisture was not significant (r = -0.181, 0.114). The research provided base information for the evaluation of restoration effects and restoration practice on the limestone mountains.


Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 826 ◽  
Author(s):  
Bayou Bunkura Allito ◽  
Nana Ewusi-Mensah ◽  
Vincent Logah

This study reports the effectiveness of some selected rhizobium strains in enhancing nitrogen fixation and nutrient uptake in Vicia faba L. Multi-location field experiments were conducted for two years (2016 and 2017) using a split-plot in randomized complete block design. Treatments comprised six rhizobium strains as the main plot factor and three varieties of Vicia faba as the sub-plot factor. Non-inoculated plants with or without N fertilizer served as +N and −N controls, respectively. Peat carrier-based inoculant of each strain was applied at the rate of 10 g kg−1 seed. Data on nodulation were taken at the late-flowering stage, whereas nitrogen and phosphorus concentrations in plant parts were analyzed at physiological maturity. The total nitrogen difference method was employed to quantify nitrogen fixation. Location x rhizobium strain x variety interaction had a significant effect on nodule dry weight plant−1. Rhizobium strains significantly enhanced nodulation, nitrogen fixation, nutrient uptake and soil nitrogen balance. Inoculation with NSFBR-12 and NSFBR-15 resulted in the highest nitrogen fixed, nutrient uptake and soil nitrogen balance. Vicia faba inoculated with the two top performing strains, NSFBR-12 and NSFBR-15 fixed respectively 87.7% and 85.5% of the total nitrogen uptake. Non-inoculated plants fulfilled proportionately more of the total nitrogen uptake through nitrogen derived from the soil rather than fixed nitrogen. Soil available phosphorus and pH had appreciable influences on nitrogen and phosphorus uptake of inoculated Vicia faba. Inoculation with competitive and effective rhizobium strains can improve soil nitrogen balance, nitrogen fixation and nutrient uptake of Vicia faba.


1991 ◽  
Vol 31 (2) ◽  
pp. 221 ◽  
Author(s):  
GJ Crocker ◽  
ICR Holford

The effects of pasture improvement on soil pH, total nitrogen, organic carbon and extractable phosphorus (P) were determined by analysing adjacent soils from improved and unimproved pastures at 67 sites on the Northern Tablelands of New South Wales. Pasture improved sites contained at least 1 clover species, predominantly white clover, and had received at least 125 kg P/ha over periods of 15-45 years. The majority of pasture improved sites contained more soil nitrogen, carbon and phosphorus and were of lower soil pH than adjacent unimproved sites. However, the decreases in pH were not statistically significant and not usually related to the magnitude of the increases in other soil fertility parameters nor to the amounts of superphosphate applied or duration of fertiliser history. The largest decline in soil pH and largest increase in organic carbon were on granitic soils which had received more than 250 kg P/ha. The relatively small decreases in soil pH and lack of relationship with fertiliser history, compared with soils from southern New South Wales, were attributed to: (i) re-cycling of legume-fixed nitrogen by summer-growing grasses; (ii) the naturally lower pH, higher nitrogen content and higher buffering capacity of many northern soils. Soil acidification therefore seems to be much slower and less frequent in the perennial pasture systems of the Northern Tablelands of New South Wales.


1989 ◽  
Vol 29 (6) ◽  
pp. 849 ◽  
Author(s):  
IG Ferris ◽  
WL Felton ◽  
JF Holland ◽  
MS Bull

Grain sorghum was sown at 2 sites at Tamworth in northern New South Wales in 1980 in order to examine the influence of fallow tillage practices and post harvest cultivation on the persistence of atrazine. In a non-cracking red clay (pH 5.7) atrazine (3.2 kg/ha) was applied both to the sorghum fallow and at sowing (1.8 kg/ha). The concentration of carryover atrazine 3 months after sorghum harvest was 0.11 µg/g in the 0-5 cm mil layer and 0.06 µg/g in the 5-15 cm layer. By contrast, the same treatment resulted in 0.61 and 0.52 µg/g in the 0-5 and 5-15 cm zones of a grey clay (pH 7.5). Cultivation after the sorghum was harvested reduced the atrazine residue in the surface soil (0-5 cm) by 20-40%, depending on the initial rate of application. There was no associated increase in the 5-15 cm zone. Despite the reduction in the amount of atrazine residue, cultivation increased the severity of atrazine injury to wheat sown at the grey clay site. There was no evidence of phytotoxicity at the red clay site.


Soil Research ◽  
1981 ◽  
Vol 19 (3) ◽  
pp. 239 ◽  
Author(s):  
ICR Holford

Changes in total and mineral nitrogen and organic carbon were measured over a nine year period in two contrasting soils of northern New South Wales after various durations of grazed lucerne, extended fallowing and continuous wheat growing. At least 2 1/2 years of lucerne ley were required to raise the total soil nitrogen above the original level on both soil types. For each year of lucerne growth the average increase (above the control treatments) in total soil nitrogen (0-15 cm) was equivalent to about 140 kg nitrogen ha-1 in the black earth and about 110 kg nitrogen ha-1 in the red-brown earth. Significantly higher levels of soil nitrogen were maintained after the lucerne treatments throughout the 9 years of measurement on the black earth and for 5 years on the red-brown earth. Lucerne had a much larger effect on nitrogen than on organic carbon, which was significantly increased only in the black earth. There were very large increases in mineral nitrogen (0-15 cm) in the first year of measurement after lucerne. Levels remained greater than they were originally for the first 4 years, and they were greater for 7 years in the black earth and 4 years in the red-brown earth following lucerne than following continuous wheat or extended fallow. The decline in mineral nitrogen during wheat cropping after lucerne was greatly increased by excessive rainfall (574 mm or more) during the fallow. Leaching was greater in the red-brown earth than in the black earth, and this explained occasional differences in nitrogen uptake by wheat between the two soil types. Some evidence suggested that under moderately moist conditions nitrogen mineralization from lucerne-fixed nitrogen was greater in the red-brown earth than in the black earth but under drier conditions it was less.


1989 ◽  
Vol 40 (6) ◽  
pp. 1143 ◽  
Author(s):  
ICR Holford ◽  
BM Haigh ◽  
IG Ferris

Wheat growing in a rotation experiment on an alkaline black earth was severely damaged by atrazine residues, whereas wheat in an adjacent experiment on a slightly acid red clay, was undamaged. Atrazine at 1.8 kg a.i, ha-1 had been applied to both sites nine months before wheat sowing. Nitrogen fertilizer had also been applied as split-plot treatments to the previous crop in each rotation sequence. There were four rotations, each comprising grain sorghum with either lucerne, an annual grain legume, long fallow, or continuous cereal growing.There were significant rotation effects on soil organic matter, pH, mineral nitrogen and residual atrazine. Organic carbon was highest, and soil pH and atrazine were lowest in the lucerne rotation, while the opposite occurred in the long fallow treatment. Atrazine concentration was positively correlated with pH and negatively correlated with organic carbon. The numbers of dead plants on the black earth were positively correlated with atrazine levels, but mortality was lowered by increasing mineral nitrogen at any particular level of atrazine.Wheat yields varied from zero in two continuous cereal plots to over 3.0 t ha-1 in a long fallow plot, and were highly correlated with mineral nitrogen levels. At any level of nitrogen, however, wheat yields were depressed by increasing levels of atrazine. The very large yield response to nitrogen, whether from soil or fertilizer, resulted from its dual beneficial effect of lowering plant mortality and improving the nitrogen status of the surviving plants.These results show that in a wheat crop following atrazine-treated sorghum, significant atrazine damage may occur on soils of pH > 64, that atrazine persistence and phytotoxicity will increase as the pH increases, but that phytotoxicity will decrease as soil nitrogen fertility increases. Lucerne rotations will lower atrazine persistence by decreasing soil pH and increasing organic matter, and will lower phytotoxicity by raising soil nitrogen.


2016 ◽  
Vol 29 (2) ◽  
pp. 274-283 ◽  
Author(s):  
Susan Elizabeth Orgill ◽  
Jason Robert Condon ◽  
Mark Kenneth Conyers ◽  
Stephen Grant Morris ◽  
Douglas John Alcock ◽  
...  

2021 ◽  
Vol 13 (3) ◽  
pp. 1541
Author(s):  
Xiaolin Shen ◽  
Lili Wang ◽  
Qichen Yang ◽  
Weiming Xiu ◽  
Gang Li ◽  
...  

Our study aimed to provide a scientific basis for an appropriate tillage management of wheat-maize rotation system, which is beneficial to the sustainable development of agriculture in the fluvo-aquic soil areas in China. Four tillage treatments were investigated after maize harvest, including rotary tillage with straw returning (RT), deep ploughing with straw returning (DP), subsoiling with straw returning (SS), and no tillage with straw mulching (NT). We evaluated soil organic carbon (SOC), dissolved organic carbon (DOC), permanganate oxidizable carbon (POXC), microbial biomass carbon (MBC), and particulate organic carbon (POC) in bulk soil and soil aggregates with five particle sizes (>5 mm, 5–2 mm, 2–1 mm, 1–0.25 mm, and <0.25 mm) under different tillage managements. Results showed that compared with RT treatment, NT treatment not only increased soil aggregate stability, but also enhanced SOC, DOC, and POC contents, especially those in large size macroaggregates. DP treatment also showed positive effects on soil aggregate stability and labile carbon fractions (DOC and POXC). Consequently, we suggest that no tillage or deep ploughing, rather than rotary tillage, could be better tillage management considering carbon storage. Meanwhile, we implied that mass fractal dimension (Dm) and POXC could be effective indicators of soil quality, as affected by tillage managements.


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