Runoff Sediment Nutrient Outflow at Different Land Slopes in Maize and Soybean Intercropping under Natural Rainfall Conditions

Abstract

newlineIntercropping is a breakthrough in land used optimization. Soil erosion have negative effect on agriculture and soil health as well as it reduces the value of land for an agricultural point of view by causing physical and chemical degradation of soil via nutrient loss through runoff and sediment. Healthy soil is the backbone of sustainable agriculture which fulfils the human requirements such as food, feed and fiber. Soil erosion is the phenomenon of sediment outflow process that erode the nutrients from agricultural and non-agricultural lands. Soil erosion is a grievous problem that affects the people all around the world. It reduces nutrient availability by washing out nutrients as well as affecting soil fertility and physical qualities. Water erosion is India most important environmental problem, consisting in topsoil loss and topographical damage. Considering the importance of erosion, this study has been done to study the effects different land slopes and cropping pattern on runoff-sediment-nutrient loss for intercropping of maize and soybean in Tarai belt of Shivalik range in the foothills of the Himalayas Uttarakhand, India. Three different land slopes (2, 5 and 8%) and four different cropping pattern (sole maize (M), intercropping of one rows of maize and soybean (M1+S1), intercropping of two row of maize and soybean (M2+S2) and with the control treatment i.e. bare) was used. Row to row and plant to plant spacing for maize crop was kept as 80 cm and 20 cm respectively and the same for the soybean as 40 cm and 7.5 cm. It was found that runoff, sediment, nitrogen, phosphorus and potassium loss occurred maximum at 8% slope under different cropping patterns such as for barren land the values are 8.33 mm, 11.65 t/ha, 9.66 kg/ha, 1.31 kg/ha and 20.24 kg/ha respectively and minimum values were observed as 2.08 mm, 0.22 t/ha, 0.37 kg/ha, 0.16 kg/ha and 0.50 kg/ha under intercropping of one row of maize and soybean at 2% land slope of the year 2020. Similar trend was observed in the year 2021 with maximum values of runoff, sediment, nitrogen, phosphorus and potassium loss at 8% slope for barren land i.e. control treatment as 10.31 mm, 14.27 t/ha 9.59 kg/ha, 1.53 kg/ha, 13.55 kg/ha respectively and minimum values for intercropping of one row of maize and soybean at 2% land slope as 3.85 mm, 0.44 t/ha, 1.04 kg/ha, 0.10 kg/ 0.56 kg/ha. The effect of two rows of maize and soybean resulted in the maximum crop growth and yield attributes followed by sole maize and intercropping of one row of maize and soybean for all land slopes. A decreasing order of runoff, sediment and nutrient losses was found for barren land, sole maize, two rows of maize and soybean, and one row of maize and soybean for a particular rainfall and land slope. Increased rainfall resulted in increased runoff and sediment outflow with corresponding increase nutrient loss at every slope. However, at a particular land slope for a given rainfall event the runoff, sediment out flow and nutrient losses have a decreasing trend in the order of barren land-sole maize-two rows of maize and soybean and one row of maize and soybean. Logarithmic relation was found between runoff and rainfall; sediment and rainfall; and nutrient loss and rainfall. Highest correlation was found between rainfall and runoff, rainfall and sediment, rainfall and nutrient loss for 5% land slope.