Precision Placement of Separated Dairy Sludge Improves Early Phosphorus Nutrition and Growth in Corn (Zea mays L.)

Abstract

Efficient use of manure nutrients by crops is necessary to minimize losses to the environment. This field study examined the possibility of replacing side-banded mineral P with precision-placed high-P sludge (6.2-11.0% dry matter) obtained after settling dairy manure slurry. The sludge was injected at about 30 kg P ha (36.0-51.2 m ha) into the soil at corn row spacing, and the corn was planted 5, 10, and 15 cm beside the injection furrow. Controls included no added P and side-banded commercial P fertilizer. The treatments were tested on corn with low and high root colonization by arbuscular mycorrhizae (AM). The study showed that sludge did not impede AM root colonization, corn germination, or seedling growth. Corn plants with both high and low levels of AM colonization responded to the sludge from the three-leaf stage and showed the greatest benefit at the six-leaf stage. Corn responded more to sludge placed at 5 than at 15 cm from the corn rows, whereas the response at the 10-cm spacing was intermediate. There was little difference in seedling growth or final harvest parameters between the side-banded fertilizer P and the 5-cm sludge treatment. The results show a new way to use manure nutrients, namely precision-placement sludge for corn. This may obviate the need for chemical fertilizers for improving farm nutrient balances. Other anticipated benefits are less energy use for hauling and injection of the sludge fraction and reduced risk of nutrient loss by runoff and volatilization (ammonia) and nuisance odors due to injection.

Availability of Phosphorus after Long‐term Whole and Separated Slurry Application to Perennial Grass prior to Corn Silage

“…These results also suggest that long‐term WS and LF applications would not impede early uptake of P or other nutrients by limiting AMF colonization in corn. The insensitivity of AMF colonization to P treatments is consistent with Kabir et al (1997) and Bittman et al (2006, 2012) but in contrast with Grant et al (2005).…”

“…In 2016, amending the control with starter P (P+) increased shoot P uptake to approximately the levels of the high WS plots with no starter (P−), but starter P increased shoot biomass and P uptake of high WS plots by >50% (34% in 2015), despite >1000 kg ha −1 net P surplus over 11 yr in these plots. These results help to explain the common farm practice of supplying corn with starter commercial fertilizer, even on soils with histories of high manure P application rates and soil‐test P (Bittman et al, 2012; Schröder et al, 2015). Overall, legacy P did not obviate the need of starter for juvenile corn.…”

“…Adequate supplies of available P near the seed and root colonization by arbuscular mycorrhizal fungi (AMF) are important for early growth of corn even in high‐P‐testing soils, and farmers frequently place (sideband) P fertilizer (referred to as “starter”) near seed at planting (Grant et al, 2005; Bittman et al, 2006). Recent studies showed that starter P could be replaced by injecting the high‐P separated sludge fraction from dairy slurry <10 cm from the seed furrow (Bittman et al, 2012; Schröder et al, 2015; Pedersen et al, 2017). The effects of repeated applications of LF vs. WS to grassland on P responses of subsequent corn crops have not been reported.…”

Optimal Placement of Meat Bone Meal Pellets to Spring Oats

“…This has previously been observed with mineral fertilizers (Rasmussen et al, 1996;Blackshaw, 2005) and animal slurry on corn (Schröder et al, 1997;Rasmussen, 2002;Petersen, 2005;Bittman et al, 2012). In the case of animal slurry, placement close to the seed row has been shown to increase yield in spring cereals (Petersen, 2005) and phosphorus (P) uptake in corn (Schröder et al, 1997;Bittman et al, 2012). Rasmussen et al (1996) observed 55% less weed biomass and 28% higher yield of spring barley after application of fertilizer close to the crop row compared with broadcasting.…”

“…This justifies pellet placement close to the row, instead of broadcasting or placement mid-way between rows, as this can increase nutrient availability for the crop and reduce it for weeds (Rasmussen et al, 1996). This has previously been observed with mineral fertilizers (Rasmussen et al, 1996;Blackshaw, 2005) and animal slurry on corn (Schröder et al, 1997;Rasmussen, 2002;Petersen, 2005;Bittman et al, 2012). In the case of animal slurry, placement close to the seed row has been shown to increase yield in spring cereals (Petersen, 2005) and phosphorus (P) uptake in corn (Schröder et al, 1997;Bittman et al, 2012).…”