VIZAG: A whopping 32.8% of India's total land area experienced a negative soil moisture anomaly in 2023, indicating vulnerability to drought stress across about 1.08 million sq km. On the other hand, approximately 47.7% of the country's land area showed positive soil moisture anomaly above historical averages, indicating wetter than usual conditions during the same period.
This positive anomaly covered around 1.57 million sq km, leading to increased risks of flooding and waterlogging in both rural and urban areas. The findings reported in a recently published study in Theoretical and Applied Climatology, ‘Unearthing India’s soil moisture anomalies: impact on agriculture and water resource strategies,’ offer important insights for policy makers.
The researchers highlighted that fluctuations in soil moisture directly affect crop yields, water availability and food security, posing unique challenges across diverse climatic zones. They compared 2023 data with historical averages from 2000 to 2005, and focused on soil moisture at depths of 0 to 10 cm.
The variability in soil moisture levels across different states and seasons suggest state-specific water management strategies are crucial for sustainable agriculture. The study advocated for the adoption of efficient irrigation techniques tailored to local conditions, citing examples where practices from states with surplus moisture could benefit those facing deficits.
The study marks the first detailed state-wise assessment of seasonal soil moisture anomalies during the pre-monsoon, monsoon and post-monsoon periods.
During winter (December-January-February), Punjab experiences positive soil moisture anomalies, averaging 1.19 mm with peaks up to 8.75 mm. This surplus moisture supports winter crops, reducing the need for additional irrigation. In contrast, Odisha faces negative soil moisture anomalies averaging -0.59 mm, indicating drier conditions compared to historical averages.
Aligning water management strategies with Punjab's practices could help mitigate these deficits. Bihar shows consistently below-average soil moisture with a mean anomaly of -1.60 mm, emphasising the need for enhanced irrigation and conservation techniques. Andhra Pradesh displays generally favourable conditions with a mean of 2.60 mm but notable variability (range: 11.02 mm), highlighting the importance of adaptable water management solutions.
Moving into the monsoon season (June-July-August-September), Punjab continues to benefit from positive soil moisture anomalies, averaging 7.86 mm with peaks up to 13.81 mm. This abundance of moisture supports robust crop growth and can be managed to prevent waterlogging.
Odisha shows improved soil moisture levels with a mean anomaly of -1.77 mm, approaching near-average conditions. Adopting techniques from Punjab could further enhance agricultural output during the monsoon.
Bihar and Jharkhand report notably below-average soil moisture, highlighting the critical need for water conservation and efficient irrigation systems to mitigate potential drought impacts. Chandigarh maintains favourable soil moisture levels with minimal variability (mean: 2.028 mm), supporting strategic agricultural planning.
During the pre-monsoon period (March-April-May), J&K exhibits high soil moisture variability (range: 26.64 mm), requiring dynamic water management strategies. Punjab maintains above-average soil moisture levels with a mean of 4.24 mm, providing stability for agricultural productivity. Odisha shows a slight deficit with a mean anomaly of -0.59 mm but benefits from shared water management practices with Punjab to mitigate pre-monsoon water stress.
Andhra Pradesh reports generally favourable conditions with a mean of 2.36 mm but with variability (range: 5.38 mm), necessitating adaptable solutions. Bihar displays below-average soil moisture with a mean of -0.32 mm, underscoring the importance of water conservation efforts. Kerala demonstrates generally favourable conditions with a mean anomaly of -2.04 mm within a moderate range (4.46 mm), emphasising sustainable farming practices. Chandigarh maintains consistent soil moisture levels with a positive mean of 0.26 mm, facilitating strategic crop planning.
The study recommended the development of region-specific policies tailored to address distinct soil moisture conditions across India. It stressed the importance of investing in advanced soil moisture monitoring systems using remote sensing and ground-based sensors to provide real-time data for informed decision-making.