Angmo Padma, Sharma Sandeep, Sidhu H S, Saini K S
Department of Soil Science, Punjab Agricultural University, Ludhiana, 141001, India.
Borlaug Institute for South Asia, Ladhowal, Ludhiana, Punjab, India, 141001.
Curr Res Microb Sci. 2024 Sep 1;7:100273. doi: 10.1016/j.crmicr.2024.100273. eCollection 2024.
Soil degradation is a major global concern due to its negative impact on soil quality and the sustainability of agricultural resources. The conservation agriculture (CA) approach, which includes three key principles such as zero tillage, retention of crop residue and crop rotation has gained widespread adoption to help mitigate the climate change effects on agricultural soils and meet the growing demand for increased production. Earthworm communities, along with microbial activity and diversity, are highly sensitive to tillage practices. Additionally, microbial activity and diversity quickly respond to different cropping systems, making them effective indicators for detecting short-term changes in soil functioning. We therefore, assess the effects of CA innovative approached after 6-years on biological and microbial diversity within earthworm cast in maize-wheat system (MWS). The treatments consist of PBM-RN/ZTW-RN (permanent beds No-N control-both residues removed and wheat with zero tillage); PBM+RN/ZTW+RN (permanent beds No-N control-both residues retained)-50% of maize stover and 25% of wheat residue retained; PBM-RN/ZTW- RN (permanent beds with 120 kg N ha both residues removed wheat with zero tillage); PBM+RN/ZTW+RN (permanent beds with 120 kg N ha both residues retained and wheat with zero tillage) and FBM-RN/CTW-RN (fresh beds in maize/CT in wheat with 120 kg N ha both residues removed). The result of present study showed that activities of carbon (C) cycle-related enzymes in the cast soils ., dehydrogenase (DHA), β-glucosidase (β-glu), cellulase, and xylanase were significantly higher under PBM+RN/ ZTW+RN than under PBM-RN/ZTW-RN. Specifically, the activities of these enzymes were 21.5, 26.8, and 76.5% higher under the PBM+RN/ZTW+RN treatment, respectively. Moreover, the Alk-P activity was found to be 1.3 times higher in the PBM+RN/ZTW+RN treatment than in the PBM-RN/ZTW-RN treatment. The bacterial, fungal, and actinomycete counts in the cast soil ranged from 6.87 to 7.47 CFU (colony forming units) x 10 g soil, 3.87-3.30 CFU x 10 g soil, and 5.09-5.67 CFU x 10 g soil, respectively. Total organic carbon (TOC) showed significant increases of 34.6% under PBM+RN/ZTW+RN as compared to PBM-RN/ZTW-RN. The less labile C (Frac. 3), total carbohydrate carbon (TCHO), phenol oxidase (PHE) and peroxidase (PER) were observed as the sensitive indicators under different tillage, rate of nitrogen and residue management practices. This study suggests that permanent beds with crop residue retention with balance fertilization practices can be recommended and popularized to the overall improvement of soil biological pools within earthworm casts in MWS.
土壤退化是一个重大的全球问题，因为它会对土壤质量和农业资源的可持续性产生负面影响。保护性农业（CA）方法包括免耕、保留作物残茬和作物轮作这三个关键原则，已被广泛采用，以帮助减轻气候变化对农业土壤的影响，并满足不断增长的增产需求。蚯蚓群落以及微生物活性和多样性对耕作方式高度敏感。此外，微生物活性和多样性会对不同的种植系统迅速做出反应，使其成为检测土壤功能短期变化的有效指标。因此，我们评估了6年后CA创新方法对玉米-小麦系统（MWS）中蚯蚓粪内生物和微生物多样性的影响。这些处理包括PBM-RN/ZTW-RN（永久床不施氮对照——去除两种残茬且小麦免耕）；PBM+RN/ZTW+RN（永久床不施氮对照——保留两种残茬）——保留50%的玉米秸秆和25%的小麦残茬；PBM-RN/ZTW-RN（永久床施120 kg N/ha，去除两种残茬且小麦免耕）；PBM+RN/ZTW+RN（永久床施120 kg N/ha，保留两种残茬且小麦免耕）以及FBM-RN/CTW-RN（玉米地新鲜床/小麦地常规耕作，施120 kg N/ha，去除两种残茬）。本研究结果表明，与PBM-RN/ZTW-RN相比，PBM+RN/ZTW+RN处理下蚯蚓粪土壤中碳（C）循环相关酶的活性，即脱氢酶（DHA）、β-葡萄糖苷酶（β-glu）、纤维素酶和木聚糖酶的活性显著更高。具体而言，在PBM+RN/ZTW+RN处理下，这些酶的活性分别高出21.5%、26.8%和76.5%。此外，发现PBM+RN/ZTW+RN处理下的碱性磷酸酶（Alk-P）活性是PBM-RN/ZTW-RN处理下的1.3倍。蚯蚓粪土壤中的细菌、真菌和放线菌数量分别在6.87至7.47 CFU（菌落形成单位）×10 g土壤、3.87 - 3.30 CFU×10 g土壤和5.09 - 5.67 CFU×10 g土壤范围内。与PBM-RN/ZTW-RN相比，PBM+RN/ZTW+RN处理下的总有机碳（TOC）显著增加了34.6%。在不同的耕作、氮肥施用量和残茬管理措施下，较难分解的碳（组分3）、总碳水化合物碳（TCHO）、酚氧化酶（PHE）和过氧化物酶（PER）被视为敏感指标。本研究表明，推荐并推广采用永久床保留作物残茬并平衡施肥的做法，有助于全面改善MWS中蚯蚓粪内的土壤生物库。
