Are horticulture-based land uses benign for fertility and health of soils in mid to high hills of the north-western Himalayan region?

Abstract

Soil fertility in many parts of the north‒western Himalayan region (NWHR) has declined owing to accelerated nutrient mining under existing crop regime. Therefore, this study aimed to assess effect of the predominant horticulture‒based land uses on soil fertility and health in mid and high hills of NWHR. Soil samples (0‒20 cm) were collected, analyzed for different soil chemical attributes (pH, electrical conductivity, organic C, available primary-, secondary-, and micro-nutrients), and compared across five key land uses: perennial grass (PG), peach orchard (PO), apple orchard (AO), field vegetable farming (VF), and protected vegetable farming (PV). Soils of the investigated land uses were neutral to near neutral in soil reaction (6.3‒6.8) except field vegetable and protected vegetable farming. Amount of soil organic C and labile organic C was significantly higher (p ≤ 0.05) in soils of apple orchards (18.6 g kg‒1 and 687.3 mg kg‒1, respectively) and peach orchards (20.4 g kg‒1 and 731.3 mg kg‒1, respectively) over others. An abrupt and significant increase in Olsen-P was recorded in soils of field vegetable farming (17.1 mg kg‒1) and protected vegetable farming (13.0 mg kg‒1), which shifted their nutrient index (NI) of P in to high category (≥ 2.33). The concentration of mineralizable-N in soil was statistically at par in soils under perennial grass and fruit orchards, while protected vegetable farming showed maximum soil mineralizable- N content (115.5 mg kg‒1) and NI of nitrogen (1.83). The NI was in high category (≥ 2.33) for copper, iron, and manganese in majority of the land uses. In view of the results, temperate fruit‒tree based land uses are benign in up‒keeping soil fertility and soil health, and needs promotion on large scale. Additionally, policies to create incentives for the build-up of soil organic matter and replenishment of the depleted soil macro and micro nutrients in vegetable-farmed lands are warranted.