| 其他摘要 | Straw is often incorporated into field by covering on soil surface or being plowed into soil in China, which may
cause problems such as competition of nutrients between soil microbes and crop because of slow decomposition of straw, and
frequent occurrence of pests and diseases when crop straw is applied into soil, thereby negatively affecting the crop yield. An
appropriate method may solve the problems above. The objectives of this study were to select an efficient straw incorporation
method that could accelerate the decomposition rate of crop straw and promote the growth of winter wheat in semi-arid region
of Shaanxi, China. To achieve these goals, a 3-year field experiment was carried out in the year of 2011－2014 at the Key
Laboratory of Agricultural Soil and Water Engineering in Area sponsored by Ministry of Education (34°18′N, 108°04′E), at
Northwest A & F University. Using summer maize straw harvested last season, two control treatments were designed including
long straw returning by covering soil (CK1), and long straw plowed into soil (CK2). In comparison, another two straw
treatments were long-ammoniated straw plowed into soil (AS) and powdered-ammoniated straw plowed into soil (PAS). The
straw decomposition rate, soil respiration, leaf area index (LAI) and aboveground biomass of winter wheat were measured
during different growth stage in the growing seasons of 2013-2014. Soil water of 0-100 cm depth during different growth
stages and winter wheat yield under different treatments in the growing season of 2011-2014 were measured. Results showed
that compared with the CK1 and CK2, the straw left in soils with the treatment AS was significantly (P<0.05) decreased by
24.31% and 13.68%, respectively, and the remaining with the treatment PAS was significantly (P<0.05) decreased by 34.64%
and 25.46%, respectively. And the treatment of ammoniated straw accelerated the decomposition rate mainly in the early
growth stage of winter wheat. The correlation coefficient between soil respiration and straw decomposition rate was 0.67
(P<0.01); Soil respiration rate of the treatment AS and PAS was significantly (P<0.05) higher than that of CK1 and CK2 in the
early winter wheat growth stage, which was increased by 109.66% and 170.13%, respectively, compared with CK1, and by
34.55% and 73.36%, respectively, compared with CK2. The variation tendency of soil water of 0-100 cm depth in
three-consecutive growing seasons during different growth stages was almost consistent. The treatment of ammoniated straw
had higher soil water storage at the late growth stage of winter wheat. The treatment PAS could significantly (P<0.05) improve
the winter wheat LAI, and promoted the accumulation of aboveground biomass. And at the mature stage of winter wheat, the
aboveground biomass for the treatment PAS was significantly (P<0.05) increased 7.02% and 9.78%, respectively, compared
with CK1, and by 5.52% and 8.25%, respectively, compared with CK2. The three-year mean winter wheat yields with AS and
PAS was higher than that of conventional straw incorporation, which was significantly (P<0.05) increased 6.13% and 9.53%,
respectively, compared with CK1 and by 3.99% and 7.32%, respectively, compared with CK2. However, the difference of
grain yield between PAS and AS was not significantly (P>0.05). The three-year mean water use efficiency (WUE) with AS and
PAS was significantly(P<0.05) increased by 5.03% and 8.73%, respectively, compared with CK1, and by 5.13% and 8.83%,
respectively, compared with CK2. And the three-year mean WUE of the treatment PAS was higher than that of the treatment
AS. Comparably, the treatment of PAS was the best among the four treatments in accelerating the straw decomposition,
promoting the growth of winter wheat, and increasing winter wheat yield and water use efficiency, which could be an effective
straw incorporation measure for winter wheat cultivation in the arid and semi arid area. |
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