scholarly journals Changes in the number of the species and fungal populations colonizing decomposing wheat crop residues

1971 ◽  
Vol 51 (2) ◽  
pp. 235-241 ◽  
Author(s):  
G. S. EMMOND

Soil aggregation was lowest in a fallow-wheat rotation and increased in other fallow-grain rotations with the second, third, and fourth crops after the fallow year. The best aggregation was under continuous wheat. Rotations containing hay crops, particularly those with grass, increased soil aggregation significantly. The influence of tillage treatments on soil aggregation declined with increased depth. Various tillage treatments affected surface soil aggregation, in the following order: green manure crop plowed under > cultivated with trash cover > crop residues plowed under > cultivated with residues burned off = crop residues disced in. Fertilizer (11–48–0) applied to the wheat crop of the various tillage treatments increased soil aggregation except where the crop residues had been removed. The application of barn manure increased soil aggregation.


2005 ◽  
Vol 56 (11) ◽  
pp. 1137 ◽  
Author(s):  
W. K. Anderson ◽  
M. A. Hamza ◽  
D. L. Sharma ◽  
M. F. D'Antuono ◽  
F. C. Hoyle ◽  
...  

Modern bread wheat (Triticum aestivum) has been well adapted for survival and production in water-limited environments since it was first domesticated in the Mediterranean basin at least 8000 years ago. Adaptation to various environments has been assisted through selection and cross-breeding for traits that contribute to high and stable yield since that time. Improvements in crop management aimed at improving yield and grain quality probably developed more slowly but the rate of change has accelerated in recent decades. Many studies have shown that the contribution to increased yield from improved management has been about double that from breeding. Both processes have proceeded in parallel, although possibly at different rates in some periods, and positive interactions between breeding and management have been responsible for greater improvements than by either process alone. In southern Australia, management of the wheat crop has focused on improvement of yield and grain quality over the last century. Adaptation has come to be equated with profitability and, recently, with long-term economic and biological viability of the production system. Early emphases on water conservation through the use of bare fallow, crop nutrition through the use of fertilisers, crop rotation with legumes, and mechanisation, have been replaced by, or supplemented with, extensive use of herbicides for weed management, reduced tillage, earlier sowing, retention of crop residues, and the use of ‘break’ crops, largely for management of root diseases. Yields from rainfed wheat crops in Western Australia have doubled since the late 1980s and water-use efficiency has also doubled. The percentage of the crop in Western Australia that qualifies for premium payments for quality has increased 3–4 fold since 1990. Both these trends have been underpinned by the gradual elimination or management of the factors that have been identified as limiting grain yield, grain quality, or long-term viability of the cropping system.


1997 ◽  
Vol 48 (1) ◽  
pp. 39 ◽  
Author(s):  
E. L. Armstrong ◽  
D. P. Heenan ◽  
J. S. Pate ◽  
M. J. Unkovich

Nitrogen balances of narrow leaf lupin (Lupinus angustifolius L.), albus lupin (L. albus L.), field pea (Pisum sativum L.), chickpea (Cicer arietinum L.), and barley (Hordeum vulgare L.) sown over a range of dates were examined in 1992 in a rotation study at Wagga Wagga, NSW. Each N budget included assessment of dependence on fixed as opposed to soil N, peak aboveground biomass N, and N removed as grain or returned as unharvested aboveground crop residues. N balances of wheat sown across the plots in 1993 were assessed similarly in terms of biomass and grain yield. Yields, N2 fixation, and crop residue N balances of the legumes were markedly influenced by sowing time, and superior performance of lupins over other species was related to higher biomass production and proportional dependence on N2 fixation, together with a poorer harvest index. Residual N balances in aboveground biomass after harvest of the 1992 crops were significantly correlated with soil mineral N at 1993 sowing and with biomass and grain N yields of the resulting wheat crop. Best mean fixation and grain N yield came from albus lupin. Wheat grain N yields following the 2 lupins were some 20% greater than after fiield pea and chickpea and 3 times greater than after barley. Net soil N balance based solely on aboveground returns of N of legumes in 1992 through to harvest of wheat in 1993 was least for narrow leaf lupin-wheat ( –20 kg N/ha), followed by albus lupin-wheat ( –44), chickpea-wheat ( –74), and field pea-wheat ( –96). Corresponding combined grain N yields (legume+wheat) from the 4 rotations were 269, 361, 178, and 229 kg N/ha, respectively. The barley-wheat rotation yielded a similarly computed soil N deficit of 67 kg/ha. Data are discussed in relation to other studies on legume-based rotations.


1998 ◽  
Vol 49 (3) ◽  
pp. 451 ◽  
Author(s):  
M. Wood ◽  
C. J. Pilbeam ◽  
H. C. Harris ◽  
J. Tuladhar

Productivity of 3 different 2-year crop rotations, namely continuous wheat, wheat-chickpea, and wheat-fallow, was measured over 4 consecutive seasons beginning in 1991-92 at the ICARDA station, Tel Hadya, Syria. Nitrogen (N) fertiliser (30 kg N/ha at sowing) was broadcast every other year in the continuous wheat only. 15N-labelled fertiliser was used to quantify the amount of nitrogen supplied to the crops through current and past applications of fertiliser and by N2 fixation. The remaining N in the crop was assumed to come from the soil. In any single season, wheat yields were unaffected by rotation or N level. However, 2-year biomass production was significantly greater (32%, on average) in the continuously cropped plots than in the wheat-fallow rotation. On average, <10% of the N in the wheat crop came from fertiliser in the season of application, and <1·2 kg N/ha of the residual fertiliser was recovered by a subsequent wheat crop. Chickpea fixed 16-48 kg N/ha, depending on the season, but a negative soil N budget was still likely because the amount of N removed in the grain was usually greater than the amount of atmospheric N2 fixed. Uptake of soil N was similar in the cereal phase of all 3 rotations (38 kg N/ha, on average), but over the whole rotation at least 33% more soil N was removed from continuously cropped plots than from the wheat-fallow rotation, suggesting that the latter is a more sustainable system. A laboratory study showed that although wheat and chickpea residues enhanced the gross rate of N mineralisation by c. 50%, net rates of N mineralisation were usually negative. Given the high C/N ratio of the residue, immobilisation, rather than loss processes, is the likely cause of the decline in the mineral N content of the soil. Consequently, decomposition of crop residues in the field may in the short term reduce rather than increase the availability of N for crop growth.


2021 ◽  
Author(s):  
Sandeep Sharma ◽  
Sukhjinder Kaur ◽  
Om Parkash Choudhary

Abstract The sustainability of rice-wheat system (RWS) in north-western India is threatened due to the deterioration of soil health and emergence of new challenges of climate change caused by low nutrient use efficiency and large scale burning of crop residues. Phosphorus and phosphatase activities in the soil aggregates affected by different residue management practices remain poorly understood. Thus, soil samples were obtained after a five year field experiment to identify the effect of tillage, green manure and residue management on aggregate-associated phosphorus fractions. In rice, the main plot treatments were combinations of wheat straw and Sesbania green manure (GM) management: (1) puddled transplanted rice (PTR) with no wheat straw (PTRW0), (2) PTR with 25% wheat stubbles (12-15 cm long) retained (PTRW25), (3) PTR without wheat straw and GM (PTRW0+GM), and (4) PTR with wheat stubbles (25%) and GM (PTRW25+GM). Three sub-plots treatments in the successive wheat crop were (1) conventional tillage with rice straw removed (CTWR0), (2) zero tillage (ZT) with rice straw removed (ZTWR0) and (3) ZT with 100% rice straw retained as surface mulch (ZTWR100). Results of the present study revealed that all phosphorus fractions were significantly higher in PTRW25+GM followed by ZTWR100 compared with PTRW0/CTWR0 treatment within both macro- and micro-aggregates. The total phosphorus (P), available P, alkaline phosphatase and phytin-P were significantly higher under ZTWR100 than CTWR0. Principal component analysis identified NaOH-Po, NaHCO3-Pi and HCl-P as the dominant and reliable indicators for evaluating P transformation within aggregates under conservation agriculture based practices.


Author(s):  
Raghubar Sahu ◽  
S. K. Mandal ◽  
K. Sharda ◽  
D. Kumar ◽  
Jubuli Sahu ◽  
...  

A field experiment was conducted during Kharif and rabi seasons of 2015 and 2016 at farmer’s field of Banka District as an On Farm Trial to study the crop residues management with different crop establishment methods in rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping system. Treatment comprised two levels of crop residue management ie. residue removal and residue retention (33%) and three levels of crop establishment methods ie. (a) conventional puddled transplanted rice fb conventional-till wheat (PTR-CTW), two times ploughing with cultivator followed by two times puddling and one planking was done before the manual transplanting of 21 days old seedling at 20 cm spacing from row to row. After rice harvesting, wheat was sown by broadcasting in conventional tillage plots with two times harrowing with cultivator followed by one planking; (b) unpuddled transplanted rice fb zero-till wheat (UPTR-ZTW): two times ploughing with cultivator followed by planking, after that water is submerged for transplanting and wet tillage was avoided. 21 days old rice seedlings were transplanted at a spacing of 20 x 15 cm. Wheat crop was sown under ZT using zero tillage machines; (c) zero-till direct-seeded rice fb zero-till wheat (ZTDSR-ZTW): direct-seeding of rice was done using zero-till seed-cum-fertilizer drill in ZT-flat plots at 20 cm row spacing. Wheat crop was sown in zero tillage using zero till machine. Rice variety (Rajendra Sweta) was sown directly by zero till in ZTDSR-ZT plots in the first fortnight of June. On the same date, rice seedlings for transplanting were raised in nursery by ‘Wet bed method’. Experiment was conducted in a split plot design which is replicated by thrice. Grain/panicle or spike, panicle or ear length and effective tillers/m2 recorded more in residue retention treatment and it was registered significantly superior with residue removal treatment under crop residue management in rice and wheat crop during both the years of experiment. Amongst crop establishment method, ZTDSR-ZTW was recorded more Grain/panicle or spike, panicle or ear length and effective tillers/m2 and it was significantly superior with UPTR-ZTW and PTR-CTW treatments under crop establishment methods in rice and wheat crop during both the years of experiment. Residues retention (33%) significantly improved the grain yield of both the component crops. For rice crop, 8.2–10.0% higher grain yield was realized with retention of crop residues. Grain and straw yield of rice were registered more in ZTDSR-ZTW (3.86-3.99 t/ha) & (5.56-5.75 t/ha) closely followed by UPTR-ZTW (4.38-4.45 t/ha). Concerning the data of residue management on economics revealed that the residue retention was recorded more gross return, net return as well as B: C ratio followed by residue removal treatment in both years of experimentation for rice and wheat crop and ZTDSR-ZTW was recorded more gross return, net return as well as B: C ratio followed by UPTR-ZTW and PTR-CTW treatments under crop establishment methods in rice and wheat crop during both the years of experiment.


1997 ◽  
Vol 48 (3) ◽  
pp. 305 ◽  
Author(s):  
I. C. R. Holford ◽  
G. J. Crocker

Six treatments were compared for their effects on wheat yields, nitrogen (N) uptake, protein content, and fertiliser N requirements in a long-term rotation study on a black earth and a red clay in northern New South Wales. Three of the treatments were lucerne, subterranean clover, and snail medic, all grown simultaneously from 1988 to 1990 and all followed by 3 years of wheat. The other 3 treatments were biennial rotations of chickpea–wheat and long-fallow–wheat as well as a continuous wheat monoculture, all lasting 6 years. With the exception of the first wheat crop, which experienced very low growing-season rainfall, lucerne was more beneficial than other legumes to following wheat crops in terms of yield, protein content, and fertiliser N requirement. Clover closely followed lucerne in the magnitude of its positive effects, whereas medic and chickpea produced much smaller effects. Because of the amount of N removed in the chickpea grain, it appeared that the small positive effects of chickpea were due to soil N sparing or rapid mineralisation from crop residues rather than any net contribution of N fixation to soil N accretion. Average yields of the 3 wheat crops following lucerne and clover were much higher than average yields 20 years previously following lucerne, even though average yields of continuously grown wheat have declined over the past 20 years. However, lucerne eliminated the need for N fertiliser for no more than 2 following wheat crops, and clover for only the first wheat crop. It appears that the longer duration of lucerne benefits reported in earlier studies was due to the higher background soil N levels as well as the lower yield potential in the earlier years. Nevertheless, lucerne lowered the fertiliser requirement of the third wheat crop by more than 50%. In contrast to lucerne, annual legumes are probably most beneficial if grown in alternate years with wheat. The large benefits of long fallowing particularly on the black earth were apparently caused by its enhancement of soil moisture and mineral N accumulation. However, these N effects were surprisingly large considering the degree of depletion of organic matter in long-fallowed soils.


Author(s):  
RAJ SINGH ◽  
SUSHIL KUMAR UPADHYAY ◽  
AMIT KUMAR ◽  
ANJU RANI ◽  
PERMOD KUMAR
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document