The long-term effect of pulse crops such as pigeonpea (Cajanus cajan L.), chickpea (Cicer arietinum L.) and mungbean (Vigna radiata L.) in crop rotation and nutrient management on soil microbial functions and enzymes activity was studied. We presumed that pulse-inclusive crop rotations and integrated nutrient management would have higher soil enzymes activity and microbial biomass carbon compared with continuous maize (Zea mays L.) - wheat (Triticum aestivum L.) rotation. We used a thirteen years old experiment in Typic Ustochrept soil of Kanpur, India. The treatments consisted of four crop rotations such as maize-wheat (MW), maize-wheat-mungbean (MWMb), maize-wheat-maize-chickpea (MWMC, two years rotation), and pigeonpea-wheat (PW) each with three levels of nutrient management treatments such as without fertilizers (control: CT), integrated nutrient management (INM), and recommended inorganic fertilizers (RDF). Crop rotations with legume in each year (PW and MWMb rotations) increased soil organic carbon (SOC), soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) compared with those of MWMC and MW (p ≤ 0.05). The PW, MWMb, and MWMC rotations increased the activity of alkaline phosphatase (20–80%), arylsulfatase (16–35%), β-glucosidase (9–16%), dehydrogenase (52–79%) and protease (5–51%) than that of MW rotation. In general, nutrient management treatments followed the order of INM > RDF ≥ CT (p ≤ 0.05) for most of the studied soil parameters. Notably, the activity of acid phosphatase, arylsulfatase and dehydrogenase enzymes was comparable in CT and RDF after thirteen years. It indicated that long-term use of chemical fertilizers could not increase these enzymes activity and warranted the need for organic amendments addition. The increased SOC and enzymes activity (particularly acid/alkaline phosphatase, β-glucosidase and arylsulfatase) in pulse-inclusive rotations were directly reflected in base-crop (wheat) productivity. The effect of crop rotations and nutrient management was mostly additive and thus an oversized increase in soil enzymes activity, SMBC and SOC was noticed in PW and MWMb with INM over the remaining crop rotations × nutrient management combinations. Thus, inclusion of pulses in crop rotation and addition of organic amendments (farmyard manure/crop residue) could be the long-term sustainable strategy to ensure optimum biological functioning of the tropical soils. The study further suggested that continuous addition of inorganic fertilizers could be detrimental to the soil enzymes activity and soil biological health in the long-run.

研究了豆科农作物如木豆（Cajanus cajan L.），鹰嘴豆（Cicer arietinum L.）和绿豆（Vigna radiata L.）对作物轮作和养分管理对土壤微生物功能和酶活性的长期影响。我们认为与连续玉米（Zea mays L.）-小麦（Triticum aestivum L.）轮作相比，包容性作物轮作和综合养分管理将具有更高的土壤酶活性和微生物生物量碳。我们在Typic Ustochrept中使用了13年的实验印度坎普尔的土壤。处理包括四个轮作，如玉米-小麦（MW），玉米-小麦-绿豆（MWMb），玉米-小麦-玉米-鹰嘴豆（MWMC，两年轮作）和木豆-小麦（PW），每三个营养管理处理的水平，例如不使用化肥（对照：CT），综合营养管理（INM）和推荐的无机肥料（RDF）。作物轮作，在每年豆科植物（PW和MWMb旋转）增加土壤的有机碳（SOC），土壤微生物量碳（SMBC）和与那些MWMC和MW相比土壤微生物氮（SMBN）（p ≤0.05）。PW，MWMb和MWMC轮换增加了碱性磷酸酶（20–80％），芳基硫酸酯酶（16–35％），β-葡萄糖苷酶（9–16％），脱氢酶（52–79％）和蛋白酶（5的活性） –51％）比兆瓦旋转。一般而言，营养管理措施遵循INM> RDF≥CT（p ≤0.05）对于大多数研究的土壤参数。值得注意的是，十三年后，CT和RDF中酸性磷酸酶，芳基硫酸酯酶和脱氢酶的活性相当。它表明长期使用化肥不能增加这些酶的活性，并保证需要添加有机改良剂。包括脉冲在内的轮作中增加的SOC和酶活性（特别是酸/碱性磷酸酶，β-葡萄糖苷酶和芳基硫酸酯酶）直接反映在基础作物（小麦）的生产力上。轮作和养分管理的影响主要是累加性的，因此在其余轮作×养分管理组合下，含INM的PW和MWMb中土壤酶活性，SMBC和SOC显着增加。从而，在作物轮作中包括脉冲并添加有机改良剂（农家肥/作物残渣）可能是确保热带土壤最佳生物学功能的长期可持续策略。研究进一步表明，长期来看，持续添加无机肥料可能对土壤酶活性和土壤生物健康有害。