Legume and Mineral N Effects on Crop Yields in Several Crop Sequences in the Upper Mississippi Valley¹

Abstract

The total effect of legumes on subsequent crop yields may be divided into two categories: (i) the effect of the N that they supply, and (ii) the net effect of all other contributions. Knowing the size of these two effects, plus the N response of the subsequent crops, allows N fertilization to be optimized for decreased energy use and for reduced pollution potential. Because the size of the legume effects vary, a study was made to estimate them on a mesic, Typic Hapludalf soil at Lancaster, Wisconsin from 1967–1976. The crop species included alfalfa (A, Medicago sativa L.), corn (C, Zea mays L.), oats (O, Avena sativa L.), and soybeans [S, Glycine max (L.) Merr.] in five crop sequences: continuous C, CSCOA, CCCOA, CCOAA, and COAAA. Four N treatments: 0, 84, 168, and 336 kg/ha were applied only to C. Crop sequence phases were assigned to whole plots in a randomized, complete block design with the N treatments in subplots. There was a highly significant effect of years on all crops due to weather variation and crop variety changes. Soybeans and A did not respond to residual N. Alfalfa yields were the same in all rotations (7.6 ± 0.04 metric tons dry matter/ha/year). The mean 0 yield (Y, quintals/ha) response to residual N (kg/ha) was described by Y = Minimum C(18.4 + 0.0354N), 24.93. Both A and S increased yields of C following these legume crops. Most of the increase was due to their N contribution, which was estimated with a Mitscherlich‐Spillman N response model as 50, 66, 51, 25, 3, 84, 24, and 71 kg N/ha to CSCOA, CSCOA, CCCOA, CCCOA, CCCOA, CCOAA, CCOAA, and COAAA, respectively. The increases in C yields above that due to the legume N were estimated as the difference between the predicted maximum rotational and continuous C yields, specifically: 11, 8, 9, 4, 4, 11, 6, and 11 quintals/ha (in the same order as above).

Residual effects of faba bean and soybean for a second or third succeeding forage-corn production

“…This synergistic relationship between 2 consecutive years of soybean (S-S-C-C) and N fertilizer for corn stover, ear and whole-plant DMY at Deschambault appeared to be due to rotation effects other than N-rotation effects, because no differences were.observed between corn from this crop sequence and monoculture at 0 kg N ha-r at both locations. In our study, rotation effects as defined by Baldock et al (1981) were not necessarily observed at the highest N level. Indeed, they defined the total rotation effect as the yield differential without N application, the rotation effects as the yield Can.…”

Nitrogen contribution of field pea in annual cropping systems. 1. Nitrogen residual effect

“…This is termed the "N benefit" of legumes. This suggests that the yield difference is due mainly to the improved soil N status following the legume (Baldock et al 1981). However, the yield gap often cannot be closed completely, indicating the involvement of some other factor(s) -the "non-N benefit" (Strong et al 1986;Wright 1990).…”

“…Non-N or secondary benefits, i.e., rotational effects, are concluded when N response curves for the second-year cereal crop in cereal-cereal and pulse-cereal sequences do not converge, even at relatively high fertilizer N rates (Baldock et al 1981). Greater uptake of soil N by crops that succeed pulses may be attributed to: the effect of legumes in breaking cereal disease and pest cycles (McEwen et al 1989;Stevenson and van Kessel 1996a); higher residual soil water after pulse crops (Elliott et al 1987); enhanced nutrient cycling due to faster breakdown of legume crop residues in the soil to release nutrients other than N; better and deeper root growth as a result of improved soil properties (Toogood and Lynch 1959), such as soil tilth (Moldenhauer et al 1983); or reduction of phytotoxic and allelopathic problems associated with cereal crop residues and release of growth-promoting substances from decomposing legume residues (Ries et al 1977).…”

Consorciação de plantas de cobertura antecedendo o milho em plantio direto: II - Nitrogênio acumulado pelo milho e produtividade de grãos

“…Ci. Solo, 28:751-762, 2004et al (1981, as plantas de cobertura podem afetar uma série de atributos do solo, tais como: a umidade, a temperatura, a aeração e o controle de pragas e moléstias ("efeito rotação"), com reflexos positivos sobre o acúmulo de N das culturas em sucessão.…”