Incorporation of maize crop residue maintains soybean yield through the stimulation of nitrogen fixation rather than residue-derived nitrogen in Mollisols
編輯:2022-10-27 14:19:08
?Crop residue amendment to soil is recommended as an effective management practice to return nutrients, especially in the maize-soybean rotation system where large amounts of maize residues are produced. Quantifying the utilisation of maize-residue N by the subsequent soybean crop is essential for optimising the N fertilisation strategy for sustainable production. However, whether and how maize residue amendment alters N acquisition in soybean plants are largely unknown. It was hypothesised that maize residue would supply N and enhance N2 fixation to meet the N requirements of subsequent soybeans. Three treatments, namely: 1) chemical fertiliser (55.2, 35.2 and 22.4 kg ha- 1 of N, P and K, respectively), 2) maize residue (8 t ha- 1), and 3) nonfertiliser were applied in a maize-soybean rotation system in a Mollisol soil. It was demonstrated that soybean seed yield in the maize-residue treatment was the same as that in the chemical fertiliser treatment, with 2.9 vs. 3.2 t ha- 1 in 2014, 2.7 vs. 2.6 t ha- 1 in 2016, and 3.0 vs. 3.1 t ha- 1 in 2018. A follow-up pot experiment using 15N-labelled residue indicated that the residue-derived N accounted for 0.5 % of the total N in soybean seeds and the proportion of symbiotically fixed N reached 82 %. The amount of fixed N during the pod-filling period in the residue treatment was 0.66 g plant-1, which was 49 % and 41 % higher than those in the chemical fertiliser and non-fertiliser treatments, respectively. The stimulation of N2 fixation was associated with an increase in fixed N per nodule and the enrichment of diazotrophs in the rhizosphere of soybean. With maize residue amendment, the increased N2-fixing capability of nodules during the reproductive period, rather than residue-derived N, fulfilled the N demand for maintaining seed yield of soybean. In the maize-soybean rotation system, maize residue amendment would facilitate the N2 fixation to partly substitute for N fertiliser for soybean production in Mollisols.
聯(lián)系我們
? ? ? ?如果我們敢想,勇于接受新觀念,樂于同我們的土壤合作而不是濫用它,我們將會看到保護(hù)性農(nóng)業(yè)是引導(dǎo)我們走向前所未見的高產(chǎn)農(nóng)業(yè)的有效途徑。這不僅是為了戰(zhàn)爭時期,更是為了戰(zhàn)后的和平年代?(Hugh?Hammond Bennett,?1943)