Hailstorms are a frequent natural weather disaster in the Canadian Prairies that can cause catastrophic damage to field crops. Assessment of damage for insurance claims requires insurance inspectors to visit individual fields and estimate damage on individual plants. This study computes temporal profiles and estimates the severity of hail damage to crops in 54 fields through the temporal analysis of vegetation indices calculated from Sentinel-2 images. The damage estimation accuracy of eight vegetative indices in different temporal analyses of delta index (pre-and post-hail differences) or area under curve (AUC) index (time profiles of index affected by hail) was compared. Hail damage was accurately quantified by using the AUC of 32 days of Normalized Difference Vegetation Indices (NDVI), Normalized Difference Water Index (NDWI), and Plant Senescence Radiation Index (PSRI). These metrics were well correlated with ground estimates of hail damage in canola (r = −0.90, RMSE = 8.24), wheat (r = −0.86, RMSE = 12.27), and lentil (r = 0.80, RMSE = 17.41). Thus, the time-series changes in vegetation indices had a good correlation with ground estimates of hail damage which may allow for more accurate assessment of the extent and severity of hail damage to crop land.

The field pea has both semi-leafless (SL) and leafed (L) types. Mixing these two types together might improve yield by optimizing pea solar radiation interception, reducing lodging, and decreasing disease. However, an optimum mixing ratio has not yet been established, since previous studies mixed two leaf types from two separate varieties. This study used four near-isogenic pairs of pea genotypes differing only in leaf type to determine the optimal mixing ratio for yield and agronomic traits. Two leaf types were mixed at seeding in five mixing ratios: 0:100, 50:50, 67:33, 83:17, and 100:0 SL/L. With precise UAV quantification of canopy height (r2 = 0.88, RMSE = 2.6 cm), the results showed that a ratio of over 67% semi-leafless pea had a 10% greater lodging resistance when compared to the leafed monoculture. For mycosphaerella blight and Uromyce viciae-fabae rust diseases, the 83:17 mixture decreased disease severity by 4% when compared with the leafed monoculture. Regression analysis of yield estimated that the 86:14 ratio provided an 11% increase to the leafed monoculture, but there was no increase compared with the semi-leafless monoculture. Mixing the two types in a high semi-leafless ratio can reduce leafed lodging and prevent yield loss but does not increase the overall yield over the semi-leafless monoculture.

Field pea (Pisum sativum L.) has two distinct leaf morphologies, leafed (L) and semileafless (SL). Grown together, SL and L pea blends have better weed control and higher crop yield than sole crops of either leaf type. Previous studies have only investigated mixing leaf types from two distinct varieties, and therefore the blend could be affected by traits specific to each pea variety rather than the difference in leaf type. To determine if yield and agronomic improvement of pea leaf blends are due solely to leaf type, this study (a) compared leaf blends of near-isogenic lines with the same varieties grown in monoculture, and (b) determined whether intercepted solar radiation, disease-resistance, lodging performance, biomass, and yield were improved by growing a varietal mixture. Five field experiments tested all possible pairings of four near-isogenic L and SL lines in a single ratio (75:25, SL/L), compared with monocultures (100% SL or 100% L). The results found that the leaf-type blends had 11% less lodging than the L monoculture and had an 8.5% greater seed yield than the L monoculture in one variety. The near-isogenic blends and non-isogenic blends did not differ significantly for foliar disease, lodging, biomass, yield, and yield stability. Consequently, the exhaustive comparison of near-isogenic or non-isogenic blends grown under multiple environments indicates that SL and L pea blends have nonsignificant yield and agronomic advantages compared with SL monocultures.