Assessment of Leaf Water Potential in a Major-Cover-Crop Continuum in Sod-Based and Conventional Cropping Systems.

The need for environmentally friendly farming systems has made sod-based rotation an important component of conservation agriculture. Integrating cover crops into rotations have also shown to benefit soil quality and productivity. In an 8-yr crop-rotation study the leaf water potential (LWP) was measured during 2008-2009 to assess plant response of both major and cover crops to moisture stress. Peanut (Arachis hypogaea L.) following by cotton-cotton (Gossypium hirsutum L.) was the continuous-row-crop rotation while sod-based rotation consist of two consecutive years bahiagrass (Paspalum notatum Flugge) following by peanut and then cotton. Oats (Avena sativa L.) were grown as cover crops between the row crops in both systems. Soil moisture status was observed throughout the same period to determine the effect of crop management (i.e. continuous-row-crop vs. sod-based rotation, fertilized vs. non-fertilized and irrigated vs. non-irrigated crops) on soil moisture and potential plant water stress. According to the measurements sod-based cotton had 1.38 MPa mean LWP while conventional (1^st and 2^nd year) crops with 1.54 and 1.52 MPa means were also in the range of well-watered plants. Similar tendency was observed for the following oat-cover crop; a 1.47 MPa LWP is detected after 2^nd year cotton vs. 1.02 MPa after sod-based cotton and 1.13 MPa for the oats following 1^st year cotton. The same trends for lower LWP in sod-based systems were seen in both major (peanut) and cover (oat) crops.