Abstract

Productivity of cropland soils, especially in arid and semi-arid tropics of India rigorously declined due to increasing losses of soil organic carbon (SOC) over the past decades. In the present study, we examined a 16-years long term experiment with continuous mono cropping rainfed groundnut (Arachis hypogaea) to quantify the influence of fertilization and manuring on yield sustainability and C sequestration potential on rainfed Vertisols of Western India. The treatments include, i) T1 = control; ii) T2 = 100% recommended dose of fertilizer [RDF-20:40:40 kg ha⁻¹ of N:P₂O₅: K₂O]; iii) T3 = integrated nutrient management [INM- 50% RDF + compost 6 Mg ha⁻¹ + biofertilizers (BF)]; iv) T4 = organic nutrient source [compost 6 Mg ha⁻¹ + vermicompost (VC) 2 Mg ha⁻¹ + castor neem cake (CNC) 250 kg ha⁻¹ + BF + mulching]. Maximum mean groundnut pod yield (1.17 Mg ha⁻¹) was recorded in T2 which was statistically similar to T4 (1.16 Mg ha⁻¹). However, Mann-Kendall test for yield trend suggests the consistency in yield increase under T3 treatment during the last 16 years. The rate of pod yield enhancement was 27 kg ha⁻¹ for every Mg increase in profile SOC stock. The mean SOC concentration (g kg⁻¹) of 1-m soil depth increased from 4.0 to 5.6 (40%) in T4 over control and the mean SOC sequestration rate was 0.63 Mg C ha⁻¹yr⁻¹. A minimum of 1.22 Mg C ha⁻¹yr⁻¹ input was needed to maintain SOC stock at its antecedent level (zero change). We conclude that combined use of chemical fertilizers along with locally available organic resources is essential for enhancing SOC storage while achieving sustainable crop productivity in semi-arid agro-ecosystem.

摘要

由于过去几十年来土壤有机碳（SOC）损失的增加，农田土壤的生产力特别是印度的干旱和半干旱热带地区急剧下降。在本研究中，我们研究了连续16年单季种植雨养花生（Arachis hypogaea）的长期实验，以定量研究施肥和施肥对印度西部雨养Vertisols产量可持续性和固碳潜力的影响。处理包括：i）T1 =对照；ii）T2 = 100％推荐肥料剂量[RDF-20：40：40 kg ha ^-1 N：P ₂ O ₅：K ₂ O]；iii）T3 =综合营养管理[INM- 50％RDF +堆肥6 Mg ha ^-1+生物肥料（BF）]；iv）T4 =有机营养源[堆肥6 Mg ha ^-1 + mi堆肥（VC）2 Mg ha ^-1 +蓖麻ne饼（CNC）250 kg ha ^-1 + BF +覆盖]。在T2中记录了花生荚的最大平均平均产量（1.17 Mg ha ^-1），其在统计学上与T4（1.16 Mg ha ^-1）相似。但是，Mann-Kendall对产量趋势的检验表明，在过去16年中，在T3处理下，产量增加的一致性。剖面SOC库存每增加Mg ，豆荚产量提高的速率为27 kg ha ^-1。T4中1-m土层的平均SOC浓度（g kg ^-1）从T4升高到4.0到5.6（40％），平均SOC封存率为0.63 Mg C ha^-1年- ^1年。至少需要输入1.22 Mg C ha ^-1 yr ^-1才能将SOC库存保持在其先前水平（零变化）。我们得出的结论是，在半干旱农业生态系统中，化学肥料与本地可用的有机资源的结合使用对于提高SOC的存储量和实现可持续的作物生产力至关重要。